CUCV crank NO START troubleshooting and questions

[Blastercanon1]

I have recently had some issues with my M1008 being hard to start, I will go through and explain all the procedures I have gone through to diagnosing my problem thus far and maybe some incite can be given for what to do next.

But first I may as well lay out what my problem started out with in the first place, because maybe others have had this problem and so others can go along if they are having the same issue so I will try my best to describe in detail. It gets decently cold where I live and usually I do not drive the truck in the winter as the road salt and wanting to keep this old gal looking as best as I can for as long as I can, and back to the point of where I live it being cold is that I had absolutely no problem starting the truck at temperatures close to 0 degrees with out the truck being plugged in. This year it has had a slow decline ever since it got cold where it has been a little more grouchy every time I go to start it but it would inevitably start, but as stated before it did not do this last winter and it has seemed to take longer and longer each time I have gone to start it. This was on a slow decline until last week it decided to not start at all, I noticed that there was no smoke coming from the tailpipe while cranking so I figured I would start with the fuel system as it appeared that I was not getting fuel. Side not for this is that the truck always smoked for a while until she warmed up all the way so to me its weird that all of a sudden there would be no smoke at all.

So to start with the fuel system here are the thing I checked thus far.
Fuel Filter
I replaced the fuel filter as I have ran around with a spare just in case and what not but I replaced the filter and bled the air from the system and then It still appeared to have e same cranking on and on with no smoke.
Fuel filter Housing
I have read on here that there is a common fail point for the fuel filter housing pertaining to a sensor that is on the Military Stanadyne box filter housing so I Once again took the filter off and it had appeared that someone before me had already to already removed and plugged the sensor hole and it appeared dry and I had figured I would rule that out for now.
Fuel Lines
Next I got under the truck to do a visual inspection of all the lines to see if there were any damp lines or loose connections where I could be leaking fuel or possibly sucking air into the fuel system, I found a couple spot where it was damp but nothing appeared to be dripping. My two areas of concern were the mechanical fuel pump on the passenger front side of the engine block and the sending unit connecting line where the hardlines appear to connect.
Mechanical fuel pump
So I figured since it was very damp around the fuel pump I figured that I would start by taking the line from the pump itself and disconnect the line going to the filter housing and put a fuel pressure gauge on it and give it a test. To the best of my knowledge these should operate around 5-8psi while the engine is turning over. Here is one of my questions that may have me back tracking a little on my troubleshooting, so The gauge reads but the needle is very erratic and using the full range of motion from 0psi mark to the 8 psi mark. I know since these pump are cam shaft driven that they will have some purging as the diaphragm moves but should it move this much or should it be holding pressure as long as I have the tester blocking the supply line out of the pump that goes into the fuel filter housing. I wrote it off as a good pump as I was getting to the desired pressure even though the needle would return to zero almost immediately and maybe it was just vacuum being puled from the diaphragm moving back down but this seemed a little bit more than I was expecting. If this does not sound right then please let me know I would really appreciate it.
Sending unit
Next since it appeared that was my other damp spot I decided to poke around there and since I had just filed the truck up the weekend before I did not want to deal with dropping a full tank of fuel so I opted for taking the bed off which took about 20 minutes for bed bolt removal and lifting the bed off from the help of a backhoe. The lines on the top of the tank did not look great by any means so I decided to replace them. I also removed the sending unit and the sock on the sending unit appeared to be fairly clogged up so I figured what the heck may as well replace the whole sending unit but the closest one had to be shipped in over night and from what I found I had to have a diesel one because of the float and the difference in diesel and gasoline in relation to fuel level reading but anyways that would get there until the next morning so I put everything back together. This included replacing the short shot fuel lines from the sending unit to the hard lines. Bled the entire system and the thing would still not start so I assumed that it wasn't the fuel lines I replaced but then I buttoned everything back up the next morning with the new sending unit. I then let it sit in the heated shop overnight and in the morning it did appear to smoke a little more like it used to so I know there was at least some fuel getting in but still no start, so even though this was not the main problem I thought it may have been contributing
Injection system
This is where my knowledge about runs out as far as how a cucv fuel system works, I have messed with old diesel tractors and dozers so that helped a lot but I am unfamiliar with this injection pump. So I did the basics of taking the lines off of the injectors and seeing if fuel was even coming out while we were bleeding air from the system and it only really appeared to weap out of the injector lines which to me was a little alarming as far as my experience goes. So I assumed that was not enough fuel pressure to acuate an injector so I put a clear hose on the IP to the return line to see if there were any bubbles in the system and sure enough there was but we appeared to bleed them all out after a lot of cranking and a lot of time letting the starter take plenty of brakes in between. There appeared to be some buildup in the injector lines that was inevitably flushed out but seemed like a strange thing that I noticed and may be important for diagnosis. So I le the truck sit over night to see if it was bleeding fuel prime off and the return line had no bubbles in it the next morning but still no starting.

I have not in fact gone and done any testing for the glow plugs or digging any deeper into if my injection pump is doing okay or that's what wrong with it as I have no idea where to start or if I can break into that pump without damaging it. there are a few things I have thought up about what I should check next including,

Glow plug systems
Injector spray patterns and checking for possibly clogged injectors
IP(Injection Pump) timing
Mechanical fuel pump ( If directed to do a test again to ensure it is working properly
Compression (Not sure what my compression rates should look like or if I have worn the engine out)

Anything else you guys think I should check or if you spot something I may have missed while trouble shooting what I have please let me know because I am willing to get my hands dirty and figure this out even though I may not be an expert. Thank you and sorry for my ramblings and possible over explanation

 

[WWRD99]

So first off....this has to be one of the best written questions I have ever seen on any online forum. You have done so much already and answered most questions. You have gotten the fuel issues figured out with the filter housing. The water sensor is usually what leaks but can be fixed with a simple o ring. That's what they removed. I do the heater o ring as well when I do one up. One thing I do getting air out of the system at the injector is only crack a few at a time. That seems to help with the low volume the lift pumps have. The clear fuel line on the ip is a great add. Can look at it and know you don't have air. One thing with that line is, you don't know if you have fuel volume. I think that's what you need and that's the lift pump. It should hold pressure if you have hooked to the hard line side. It shouldn't go to 0 to 8 up and down. You can put a longer hose into a bottle off the ip and see if fuel comes out strong. That would solidify it. Could be a trickle. The next step is to replace the glow plugs...especially if you haven't in the last 2 years. Check voltage at the relay output and see that it is 12 volts and not much higher if you have the resistor hooked up still. Check the big wire on the bottom of the relay that should be the output with the relay turned on. Being it was a gradual slow start I'd go with both. Not a hard job considering all the other stuff you have already done. As far as glow plugs there is the 13g that will fit the stock connectors easy but are getting more difficult to find. The diesel DRX00070 is a great stock replacement and can be found pretty easy. If you have the large connectors the 60g is the replacement. How to tell...the stock connectors are either thin black or gray...anything else like crimp connectors is usually the large 60g size. You might be able to read the old glow plugs and see what was in there too.
As far as fuel pumps I have bought many from this guy on ebay, old NOS ones that have worked for years. Yes crazy cheap too. I have 3 in the cabinet for the ones I haven't changed yet. It takes 2 of us about 20 minutes to change one....my son up top starting the bolts and me down below holding the pump in place. I assume you know to pull the cover and grease the fuel pump shaft to hold it in place. Install the plate, then loosely install the pump bolts and install the steel line first before you tighten everything at once.
So recap, I would test fuel volume and voltage at the relay and go from there. These don't like to start without glows even when hot.

 

[Blastercanon1]

I really appreciate the compliment about the post being written up so well, I really tried to be thorough and be as specific as I possibly could if not to help with the diagnosis and guidance to finding the solution but also to help any others who may be experiencing or going to experience this problem in the future and sort of pass it along to the next guy that needs it. I was very relieved to find that the heavy lifting with the filter housing was already taken care of because it appears they have become very scarce even sourcing a used one off a civi 6.2. You could probably tell when reading my post that even I had my doubts about the mechanical lift/fuel pump being completely checked off my list because I've never really had to test one before because on my older gasoline pickups I always either had the diaphragm give out completely or it starts leaking real bad in between the crimp seal is on the pump and it makes a big puddle. Being that it is a diesel and its not the only fuel pump I figured its a necessity to check with it supplying the IP and that is a part that would rest heavy on my wallet if I overlooked it even if it had not failed all the way and was just starting to wear out I want to get ahead of any issues before they are presented in such a dramatic way like the IP burning itself up. I am thinking that I will be able to get to the Glow plugs hopefully sometime this week and from the sounds of it I may have to remove the injector to retrieve any pieces of glow plug if they broke inside the pre detonation chamber next to the injector, I was thinking I would do a compression test while the injectors are out and possibly watch the injectors to make sure they have a good spray pattern as the truck did smoke a lot before this happened and maybe its more so glow plugs considering the problem I am currently facing. It might be important to add that while it was warming up one side did always smoke more than the other so this may point to the isolation of which bank is acting up weather it is a leaking injector or one side of my glow plug banks is malfunctioning over the other. I am not sure if that has anything to do with it as far as a symptom of that or something else at this point but it could go either way. A little trick I was taught by my grandfather who used to work in a few shops including the GM dealership in the 70s and 80s was when they used to change them they would pack the hole with grease and that would help lubricate the shaft and also hold the pump in place and eventually the grease would eventually break down and assured me that engine damage would not occur from all the extra grease in there. That being said it still does not make the pump being in the position that it is any more convenient. One thing I was thinking was possibly plug the block heater in and see if I get any difference as it is almost hard freezing every night now and the truck is cold after park it for very little time and see if that makes an improvement and then chase the problem in which ever direction it leads me weather it start easier or starts at all i guess. better than I had it running well consistently in the summer.

 

[Mullaney]

I really appreciate the compliment about the post being written up so well, I really tried to be thorough and be as specific as I possibly could if not to help with the diagnosis and guidance to finding the solution but also to help any others who may be experiencing or going to experience this problem in the future and sort of pass it along to the next guy that needs it. I was very relieved to find that the heavy lifting with the filter housing was already taken care of because it appears they have become very scarce even sourcing a used one off a civi 6.2. You could probably tell when reading my post that even I had my doubts about the mechanical lift/fuel pump being completely checked off my list because I've never really had to test one before because on my older gasoline pickups I always either had the diaphragm give out completely or it starts leaking real bad in between the crimp seal is on the pump and it makes a big puddle. Being that it is a diesel and its not the only fuel pump I figured its a necessity to check with it supplying the IP and that is a part that would rest heavy on my wallet if I overlooked it even if it had not failed all the way and was just starting to wear out I want to get ahead of any issues before they are presented in such a dramatic way like the IP burning itself up. I am thinking that I will be able to get to the Glow plugs hopefully sometime this week and from the sounds of it I may have to remove the injector to retrieve any pieces of glow plug if they broke inside the pre detonation chamber next to the injector, I was thinking I would do a compression test while the injectors are out and possibly watch the injectors to make sure they have a good spray pattern as the truck did smoke a lot before this happened and maybe its more so glow plugs considering the problem I am currently facing. It might be important to add that while it was warming up one side did always smoke more than the other so this may point to the isolation of which bank is acting up weather it is a leaking injector or one side of my glow plug banks is malfunctioning over the other. I am not sure if that has anything to do with it as far as a symptom of that or something else at this point but it could go either way. A little trick I was taught by my grandfather who used to work in a few shops including the GM dealership in the 70s and 80s was when they used to change them they would pack the hole with grease and that would help lubricate the shaft and also hold the pump in place and eventually the grease would eventually break down and assured me that engine damage would not occur from all the extra grease in there. That being said it still does not make the pump being in the position that it is any more convenient. One thing I was thinking was possibly plug the block heater in and see if I get any difference as it is almost hard freezing every night now and the truck is cold after park it for very little time and see if that makes an improvement and then chase the problem in which ever direction it leads me weather it start easier or starts at all i guess. better than I had it running well consistently in the summer.

.
Sounds to me like the fuel pump (lift pump) as well detailed by @WWRD99 .
Yep, that trick with the grease on the pushing rod will help installation A LOT.

Just don't forget that testing the lift pump is worth your time.
Rather than pointing the parts cannon at it...

Repeating what was said before, well written post. (both of them!)

 

[WWRD99]

I really appreciate the compliment about the post being written up so well, I really tried to be thorough and be as specific as I possibly could if not to help with the diagnosis and guidance to finding the solution but also to help any others who may be experiencing or going to experience this problem in the future and sort of pass it along to the next guy that needs it. I was very relieved to find that the heavy lifting with the filter housing was already taken care of because it appears they have become very scarce even sourcing a used one off a civi 6.2. You could probably tell when reading my post that even I had my doubts about the mechanical lift/fuel pump being completely checked off my list because I've never really had to test one before because on my older gasoline pickups I always either had the diaphragm give out completely or it starts leaking real bad in between the crimp seal is on the pump and it makes a big puddle. Being that it is a diesel and its not the only fuel pump I figured its a necessity to check with it supplying the IP and that is a part that would rest heavy on my wallet if I overlooked it even if it had not failed all the way and was just starting to wear out I want to get ahead of any issues before they are presented in such a dramatic way like the IP burning itself up. I am thinking that I will be able to get to the Glow plugs hopefully sometime this week and from the sounds of it I may have to remove the injector to retrieve any pieces of glow plug if they broke inside the pre detonation chamber next to the injector, I was thinking I would do a compression test while the injectors are out and possibly watch the injectors to make sure they have a good spray pattern as the truck did smoke a lot before this happened and maybe its more so glow plugs considering the problem I am currently facing. It might be important to add that while it was warming up one side did always smoke more than the other so this may point to the isolation of which bank is acting up weather it is a leaking injector or one side of my glow plug banks is malfunctioning over the other. I am not sure if that has anything to do with it as far as a symptom of that or something else at this point but it could go either way. A little trick I was taught by my grandfather who used to work in a few shops including the GM dealership in the 70s and 80s was when they used to change them they would pack the hole with grease and that would help lubricate the shaft and also hold the pump in place and eventually the grease would eventually break down and assured me that engine damage would not occur from all the extra grease in there. That being said it still does not make the pump being in the position that it is any more convenient. One thing I was thinking was possibly plug the block heater in and see if I get any difference as it is almost hard freezing every night now and the truck is cold after park it for very little time and see if that makes an improvement and then chase the problem in which ever direction it leads me weather it start easier or starts at all i guess. better than I had it running well consistently in the summer.

Having the truck smoke when warming up really points to the glow plugs on that bank are ded. These trucks really do not like to start without glow plugs even warmed up after sitting a short time. I wouldn't go through the testing of injectors and such yet. Smoking doesn't mean to much fuel from a bad injector but a bad glow plug not getting the fuel to fire when cold. The compression test is done through the glow plug hole anyhow. The block heater might help some but the most it will do is decrease the amount of time the glow plugs pre run before the light goes out....which if glow plugs are bad, it won't really change anything. I have mine plugged in, it does start super easy and it is nice having heat pretty quick but that's the main advantage of plugging in though. Getting the glow plugs out is a hit and miss. Sometimes just spinning them and spraying carb cleaner into the threads, with the straw attached, knocks the carbon off the end and it comes out. Obviously it needs to be turned out past the threads to get that part to work. If the steel end has bulged out then it can take more work to get out but spend time spinning the glow plug by hand trying to get it out. What I am getting at is don't ramajammit prybar come out now. That will only cost you a lot more time. If you end up needing the tool to press it out, again, take it slow and try not to break the end off. Sometimes you can stretch it out before it breaks and come out. If it does not really a big deal as removing the injector isn't that tough and a pen magnet gets it out of the precup. The return lines might need replaced since those little clamps like to turn into dust when touched. If you have an advanced auto parts out your way they sell precut lines and clamps made out of viton. Pretty slick stuff and works. If you can get help doing the lift pump I would highly advise it. Even if the other person just holds the pump in place from underneath for 2 minutes while you pop in the bolts from up top would make you not have to look for tools that got chucked across the yard. I use an old sleeping bag to lay on the engine so I don't get gutted by the hood latch. If not removing the passenger side alternator will make it easier by yourself but still sucks. I do glue the gasket to the new pump the day before just so it doesn't move when installing as well. Side note on turning these engines over a bunch, is to make sure you have the front bracket bolted tight to the block and the starter and the starter bolts are tight....verified not looking. Charge the batteries all the time while this process is going too. Don't want any amp ups and voltage drops as that creates all kinds of smoke!

 

[Blastercanon1]

Having the truck smoke when warming up really points to the glow plugs on that bank are ded. These trucks really do not like to start without glow plugs even warmed up after sitting a short time. I wouldn't go through the testing of injectors and such yet. Smoking doesn't mean to much fuel from a bad injector but a bad glow plug not getting the fuel to fire when cold. The compression test is done through the glow plug hole anyhow. The block heater might help some but the most it will do is decrease the amount of time the glow plugs pre run before the light goes out....which if glow plugs are bad, it won't really change anything. I have mine plugged in, it does start super easy and it is nice having heat pretty quick but that's the main advantage of plugging in though. Getting the glow plugs out is a hit and miss. Sometimes just spinning them and spraying carb cleaner into the threads, with the straw attached, knocks the carbon off the end and it comes out. Obviously it needs to be turned out past the threads to get that part to work. If the steel end has bulged out then it can take more work to get out but spend time spinning the glow plug by hand trying to get it out. What I am getting at is don't ramajammit prybar come out now. That will only cost you a lot more time. If you end up needing the tool to press it out, again, take it slow and try not to break the end off. Sometimes you can stretch it out before it breaks and come out. If it does not really a big deal as removing the injector isn't that tough and a pen magnet gets it out of the precup. The return lines might need replaced since those little clamps like to turn into dust when touched. If you have an advanced auto parts out your way they sell precut lines and clamps made out of viton. Pretty slick stuff and works. If you can get help doing the lift pump I would highly advise it. Even if the other person just holds the pump in place from underneath for 2 minutes while you pop in the bolts from up top would make you not have to look for tools that got chucked across the yard. I use an old sleeping bag to lay on the engine so I don't get gutted by the hood latch. If not removing the passenger side alternator will make it easier by yourself but still sucks. I do glue the gasket to the new pump the day before just so it doesn't move when installing as well. Side note on turning these engines over a bunch, is to make sure you have the front bracket bolted tight to the block and the starter and the starter bolts are tight....verified not looking. Charge the batteries all the time while this process is going too. Don't want any amp ups and voltage drops as that creates all kinds of smoke!

Okay good to know I do not know if I want to replace the lift pump and then try and fire it up before I do the glow plugs because from what it sounds like there are diffidently some that are toast at this point from what it sounds like, but if I had to put money on it I would say that it has a failing lift pump and the glow plugs are what is causing it not to fire. That's nice to know that the compression tester would thread into the glow plug hole so I may as well test each cylinder as I go along I figure just out of pure curiosity, but ill have to find the specs for what these cylinders are supposed to run at. I forgot that the glow plugs read off of the temp sensor to regulate how long they stay on I assume as the glow plugs really do not cycle at all or for as long as they do after I did run the engine for while, this is also the reason why I do not think its my relay or my controller card... at this moment in time, talk about an expensive part, so with that in mind I think that as much fun as it would be to go through and only replace the bad ones I think that they all might be on their last leg as far a function ability goes. With the glow plug removal I have seen a tool on ebay that may help with the removal of the glow plugs, do you have any experience in using the "Glow Plug Removal Tool" I can not remember the exact name for it or who makes them but it looks like it goes around the glow plug and plus it out like a traditional puller(kind of) at least that is what i can infer from just looking at it I may be completely wrong. I was noticing that some of my lines underneath were starting to become a little dry rotted including the vacuum lines that I assume go to that sensor or what not on the injection pump and I am not sure exactly what it does but my guess was that it is for the elevated idle but my guess could be completely wrong that is just my guess. That is besides the point but also thought maybe that had something to do with it not starting but not enough to be the main problem if it was in fact the "high idle" or something to do with that nature. I like that idea of gluing the gasket onto the pump the night before as I know I have cussed up a storm trying to get those little b*sterds to stay in place on the gasoline vehicles. I have known people and heard many horror stories about people shearing off the starter bolts and having to put a helix coil in the block down there and I have checked them right after I put the bed back on as I was down there anyways but I have tried to be religious about keeping those batteries alive as they are the big ones that the military would put in them and I would like to keep it as original appearing as I possibly can and I do not know the first second or third place I would even try looking for those batteries once they go bad but I need to put those on the charger for sure as they have been put to work this last weekend and killing them is the last thing I want, I do not want to add two batteries and a 24volt starter to the mix of parts I need to replace at this point.

 

[deank]

I have experienced the swollen glow plugs. When I had swollen one in hummers on active duty and on my M1031, my removal tool was a wrench that just fit over the threads of the glow plug so I could apply outward pressure on the glowplug while backing out the plug by threading it out. Once the threadcutting was well started I would use needlenose visegrips to back the plug all the way out. I have fortunately never experienced breaking one off.

 

[Barrman]

Mechanical lift pump psi testing. I have a gauge on my M715. Between the metal hard line above the passenger valve cover and the fuel filter. It bounces between 5-8 psi with the engine running. But, never below 4. I just walked out and looked at the mechanical gauge and it reads 5 psi and I haven’t started the engine in almost 2 weeks. The psi should hold unless there is a leak at one end or the other is my experience and point.

Wet spots on fuel hose. Air molecules are smaller than diesel liquid molecules. If you see wet spots on the outside of the hose. That means air can get sucked into the hose. Such a leak will keep running your IP dry unless you replace the hoses.

Wet lift pump. I have had 2 with the exact same wet pumps the last few months. I replaced 1 a few weeks ago. It was pumping fuel out the weep hole. The other truck actually left a little puddle on the ground when it was hot out. Now that we are below 40° it is dry as a bone and no puddle. I will replace that pump in a few days because I know it will need it.

Hoses with no wet spots. One of my trucks was running great a few years ago. My son brought a girl to the house to meet us and took her for a drive in the truck. They got back and he said it kept turning off and had to be cranked like crazy to get started again. I did just about all the stuff you documented in the original post and finally solved it with the hose from the filter to the IP. It was old and cracked enough to let air in when bouncing down the road. My point is check everything and if a hose is more than 5 years old. Replacing it might be a good idea. Even if it isn’t your problem today. By the way, she ended up marrying him and the truck now lives at their house.

 

[Blastercanon1]

I have experienced the swollen glow plugs. When I had swollen one in hummers on active duty and on my M1031, my removal tool was a wrench that just fit over the threads of the glow plug so I could apply outward pressure on the glowplug while backing out the plug by threading it out. Once the threadcutting was well started I would use needlenose visegrips to back the plug all the way out. I have fortunately never experienced breaking one off.

That is a really good tip and saves some money as far as the removal process for them, I did not know if the tool was a must have or rather made the job easier. I am really hoping and praying that I do not have to remove any injectors to fish out any broken glow plug bits and pieces. Still might order the tool or give it a shot at removing them the way you explained in your post above.

Mechanical lift pump psi testing. I have a gauge on my M715. Between the metal hard line above the passenger valve cover and the fuel filter. It bounces between 5-8 psi with the engine running. But, never below 4. I just walked out and looked at the mechanical gauge and it reads 5 psi and I haven’t started the engine in almost 2 weeks. The psi should hold unless there is a leak at one end or the other is my experience and point.

Wet spots on fuel hose. Air molecules are smaller than diesel liquid molecules. If you see wet spots on the outside of the hose. That means air can get sucked into the hose. Such a leak will keep running your IP dry unless you replace the hoses.

Wet lift pump. I have had 2 with the exact same wet pumps the last few months. I replaced 1 a few weeks ago. It was pumping fuel out the weep hole. The other truck actually left a little puddle on the ground when it was hot out. Now that we are below 40° it is dry as a bone and no puddle. I will replace that pump in a few days because I know it will need it.

Hoses with no wet spots. One of my trucks was running great a few years ago. My son brought a girl to the house to meet us and took her for a drive in the truck. They got back and he said it kept turning off and had to be cranked like crazy to get started again. I did just about all the stuff you documented in the original post and finally solved it with the hose from the filter to the IP. It was old and cracked enough to let air in when bouncing down the road. My point is check everything and if a hose is more than 5 years old. Replacing it might be a good idea. Even if it isn’t your problem today. By the way, she ended up marrying him and the truck now lives at their house.

I think that I may install an inline pressure gauge just so if I even have the hunch that I am loosing the lift pump again then I do not have to tear apart anything for that sequence of troubleshooting, I also appreciate the incite and help as far as telling me what the the parameters of how everyone else's lift pump are functioning and if it was acting abnormal in accordance to the test I ran.

 

[Blastercanon1]

So it has been a week or two since I last posted about the problem I was having with the crank no start, I decided to go after the glow plug system. I ended up also finding that my starter was very very un happy with my cranking and with time I guess it just decided it was fed up with the abuse of how much cranking I had done with so I removed the starter and long story short it was not pretty on the inside
Glow plug system trouble shooting
I started off by just flat out removing them and testing each one, luckily none were swollen or broken where I had to do any recovery in the pre det chamber so I was very fortunate for that, I then took each glow plug and “bench tested” them by using jump wires off of a jump box and spraying some penetrating fluid on the tip of each glow and then turning the jump pack on and seeing if the oil started to burn off. To my surprise all 8 were not functioning at all, I was in sure of my testing method so I grabbed one of the new ones and did the same test and the oil started to burn off of the glow plug. So I installed all of the glow plugs and then re attached the batteries and let them cycle once and then it started up faster than I have ever heard it do so before. I was very pleased to find that was my starting issue BUT…. I noticed smoke coming from my firewall and smelt a burning smell, I immediately shut off the truck and started to investigate, my first thought was maybe the wire coming from the battery to the power block on the fire wall because that’s about where I saw the smoke rising from, and in my head I didn’t think that wire coming from the two batteries should be going to a power block that is 12 volt when I test it. I noticed that wire was not getting hot at all and started to look down where I figured the smoke must be coming from, I found out what it was but Iam not sure why it went bad or how it went bad, the thing that was smoking was the two giant resistors on the firewall, so I immediately disconnected the batteries and detached it from the firewall, d*mn near burning my fingers it was so hot. I used my multimeter and it was reading .5 ohms of resistance which Iam unsure if that reads out well so I disassembled it and realized that the only thing keeping these resistors from grounding out to the mount are these clear plastic “washers” that keep it from grounding out into the bracket that the resistors attach to. View attachment IMG_4479.jpegView attachment IMG_4486.jpeg
the plastic pieces are almost translucent at this point and very brittle. With a little bit of poking around I figure since that was obviously not doing its job I must have been pushing 24 volts into my glowplug relay and then into the glow plugs which ended up burning them out. So with this in mind I started thinking why didn’t they just attach it straight to the power block right above it, then that had me thinking of why they would do a separate system for them more direct from the 24 volt side and I figure that was Probrbaly because how much draw the flow plugs have so my solution and I’ll see what you guys think, but I think Iam going to get rid of the resistor and go straight to the first terminal on the second battery on its own wire so it draws the 12.5 it needs straight off the battery. View attachment IMG_4482.jpeg
as you can see where the wire that is disconnected is at I read 12.5 volts and so that’s where I imagine I am going to attach the wire for the power to the glowplug solenoid and then I have no issue with drawing too much power off the 12 volt power block and like I stated before come right off the battery.
My other option I would imagine is find a better insulator for the space where those plastic washers were at but I think then I would be keeping a fail point in my system where I don’t necessarily have to. I imagine one of the few downsides of this is that it main affect the life of the front battery instead of having it taken off the batteries in series which is why I imagine they did the resistors in the first place but that is just my speculation alone.
Here are some picture of what the glow plugs worked out to be when I removed them as they do not look terrible but they don’t ohm out so I think it’s a good example of just because it looks alright doesn’t mean it works properly.
Tell me what you guys think of my “resistor override” idea and if it will work in practice and if my theory is incorrect thank you

 

[Barrman]

Removing the resistor in the glow plug circuit is a fairly common practice. It does have a few down sides which you mentioned. Here is a video about bypassing the resistor issues.

 

[WWRD99]

So it has been a week or two since I last posted about the problem I was having with the crank no start, I decided to go after the glow plug system. I ended up also finding that my starter was very very un happy with my cranking and with time I guess it just decided it was fed up with the abuse of how much cranking I had done with so I removed the starter and long story short it was not pretty on the inside
View attachment 939328View attachment 939329Glow plug system trouble shooting
I started off by just flat out removing them and testing each one, luckily none were swollen or broken where I had to do any recovery in the pre det chamber so I was very fortunate for that, I then took each glow plug and “bench tested” them by using jump wires off of a jump box and spraying some penetrating fluid on the tip of each glow and then turning the jump pack on and seeing if the oil started to burn off. To my surprise all 8 were not functioning at all, I was in sure of my testing method so I grabbed one of the new ones and did the same test and the oil started to burn off of the glow plug. So I installed all of the glow plugs and then re attached the batteries and let them cycle once and then it started up faster than I have ever heard it do so before. I was very pleased to find that was my starting issue BUT…. I noticed smoke coming from my firewall and smelt a burning smell, I immediately shut off the truck and started to investigate, my first thought was maybe the wire coming from the battery to the power block on the fire wall because that’s about where I saw the smoke rising from, and in my head I didn’t think that wire coming from the two batteries should be going to a power block that is 12 volt when I test it. I noticed that wire was not getting hot at all and started to look down where I figured the smoke must be coming from, I found out what it was but Iam not sure why it went bad or how it went bad, the thing that was smoking was the two giant resistors on the firewall, so I immediately disconnected the batteries and detached it from the firewall, d*mn near burning my fingers it was so hot. I used my multimeter and it was reading .5 ohms of resistance which Iam unsure if that reads out well so I disassembled it and realized that the only thing keeping these resistors from grounding out to the mount are these clear plastic “washers” that keep it from grounding out into the bracket that the resistors attach to. View attachment 939340View attachment 939341View attachment 939342
the plastic pieces are almost translucent at this point and very brittle. With a little bit of poking around I figure since that was obviously not doing its job I must have been pushing 24 volts into my glowplug relay and then into the glow plugs which ended up burning them out. So with this in mind I started thinking why didn’t they just attach it straight to the power block right above it, then that had me thinking of why they would do a separate system for them more direct from the 24 volt side and I figure that was Probrbaly because how much draw the flow plugs have so my solution and I’ll see what you guys think, but I think Iam going to get rid of the resistor and go straight to the first terminal on the second battery on its own wire so it draws the 12.5 it needs straight off the battery. View attachment 939343
as you can see where the wire that is disconnected is at I read 12.5 volts and so that’s where I imagine I am going to attach the wire for the power to the glowplug solenoid and then I have no issue with drawing too much power off the 12 volt power block and like I stated before come right off the battery.
My other option I would imagine is find a better insulator for the space where those plastic washers were at but I think then I would be keeping a fail point in my system where I don’t necessarily have to. I imagine one of the few downsides of this is that it main affect the life of the front battery instead of having it taken off the batteries in series which is why I imagine they did the resistors in the first place but that is just my speculation alone.
Here are some picture of what the glow plugs worked out to be when I removed them as they do not look terrible but they don’t ohm out so I think it’s a good example of just because it looks alright doesn’t mean it works properly.View attachment 939344
Tell me what you guys think of my “resistor override” idea and if it will work in practice and if my theory is incorrect thank you

This makes me happy. I'm glad you got it figured out. Without wiring the resistor back in and testing the voltage on the output side there's no way to know if it's not dropping the volts to 12. Since the glows weren't working the resistor hasn't gotten hot in a long time so all that engine dust and grime tends to smoke now that it's pulling 80 plus amps through it. No big deal though since taking the wire off the output of the resistor and wiring it to the 12 volt block works fine. That's how mine are since the resistor didn't resist anymore. I'd like to find a resistor that I could replace it with though. I'd really like to keep both batteries powering the glow plugs. I have to keep up with the one batteries water and acid a good bit vs the other that just runs the starter in tandem. I have the same batteries you do. Can you tell what glow plugs were in it? Which ones did you go with?

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[Blastercanon1]

Thank you guys for the comments back on the issue I was having with my M1008, I hooked up my glow plug relay directly to the battery and the video really helped me visualize how I was going to do it so I really appreciate you sourcing that video. So far so good on it and it runs smooth and there is a little bit of haze out the exhaust but nothing compared to what it was, my buddies would tell me that I had a built in smoke screen when I would start it haha. It has been very cold the past few days like low teens and a very cold north wind to chill her off overnight and she starts right up after a very long first glow plug cycle but none the less it starts great. I do have a small issue with the used starter I got from the local MV salvage yard but I mean I can not be all too upset with the fact that it is a used starter. Basically the starter sometimes with stick and I can hear a big clunk not just the noise of the solenoid I believe and then I get nothing out of it as far as rotational force, and this was very discouraging as to I now had a no crank no start issue. It seems I keep chasing different versions of my original problem. So since the variable that I had changed were 1. the way the glow plug relay is getting power straight to the first battery and I had just worn that batteries capability to draw a strong current out of it sooner than I thought 2. I have a different starter in the truck now of which I do not know condition of internals. SO I started with the batteries and disconnected them from the truck and then separated the two batteries and to start I checked the voltage of each which read 12.7 roughly which means that the batteries are holding voltage but I know that does not mean I do not have worn out batteries. So I put a battery tester on each battery and they both read about 830cca which at least to me those batteries still have some very decent life left on them. That lead me to checking out the starter, so I had a second person turning the key over while I would lightly tap the starter with a hammer and then the starter was knocked loose and cranking strong like nothing ever happened (For Now). I know for the most part this probably mean either my solenoid or my brushes in that "new" used 24v starter I have are on their way out maybe, but I was wondering and maybe someone can help answer this for me but is it possible that it has a bit of corrosion on the inside of it and who knows how long that starter has been sitting around but wondering if that's a realistic possibility. Don't get me wrong I love wrenching on old stuff and the cucvs are a good challenge to figuring out the unique electrical system on it in comparison to a traditional strictly 12 volt system but I am starting to wonder where my chasing small problems like this is going to end. I can not complain about the originality of the truck as I have found some vehicles that the electrical system is held together with wire nuts and crossed wires covered by electrical tape, basically fires waiting to happen and I am yet to run into something like that on this truck so it is a breath of fresh air for sure. I will say that trying to find a 6 foot section of 6 gauge wire was like pulling teeth, I went to 2 auto parts stores and then about 5 different hardware stores for that 6 gauge wire but its done so I am certainly happen about that, probably could have had the truck all buttoned up and squared away about 2 hours earlier if it were not for the wild goose chase I had to go on around town. Overall this truck is starting to give me emotionally abusive Ex treatment if you know what I mean haha, but seriously let me know if I will be fine with the starter I just put on or if I should try to exchange that one for a different one thank you!

 

[Mullaney]

Thank you guys for the comments back on the issue I was having with my M1008, I hooked up my glow plug relay directly to the battery and the video really helped me visualize how I was going to do it so I really appreciate you sourcing that video. So far so good on it and it runs smooth and there is a little bit of haze out the exhaust but nothing compared to what it was, my buddies would tell me that I had a built in smoke screen when I would start it haha. It has been very cold the past few days like low teens and a very cold north wind to chill her off overnight and she starts right up after a very long first glow plug cycle but none the less it starts great. I do have a small issue with the used starter I got from the local MV salvage yard but I mean I can not be all too upset with the fact that it is a used starter. Basically the starter sometimes with stick and I can hear a big clunk not just the noise of the solenoid I believe and then I get nothing out of it as far as rotational force, and this was very discouraging as to I now had a no crank no start issue. It seems I keep chasing different versions of my original problem. So since the variable that I had changed were 1. the way the glow plug relay is getting power straight to the first battery and I had just worn that batteries capability to draw a strong current out of it sooner than I thought 2. I have a different starter in the truck now of which I do not know condition of internals. SO I started with the batteries and disconnected them from the truck and then separated the two batteries and to start I checked the voltage of each which read 12.7 roughly which means that the batteries are holding voltage but I know that does not mean I do not have worn out batteries. So I put a battery tester on each battery and they both read about 830cca which at least to me those batteries still have some very decent life left on them. That lead me to checking out the starter, so I had a second person turning the key over while I would lightly tap the starter with a hammer and then the starter was knocked loose and cranking strong like nothing ever happened (For Now). I know for the most part this probably mean either my solenoid or my brushes in that "new" used 24v starter I have are on their way out maybe, but I was wondering and maybe someone can help answer this for me but is it possible that it has a bit of corrosion on the inside of it and who knows how long that starter has been sitting around but wondering if that's a realistic possibility. Don't get me wrong I love wrenching on old stuff and the cucvs are a good challenge to figuring out the unique electrical system on it in comparison to a traditional strictly 12 volt system but I am starting to wonder where my chasing small problems like this is going to end. I can not complain about the originality of the truck as I have found some vehicles that the electrical system is held together with wire nuts and crossed wires covered by electrical tape, basically fires waiting to happen and I am yet to run into something like that on this truck so it is a breath of fresh air for sure. I will say that trying to find a 6 foot section of 6 gauge wire was like pulling teeth, I went to 2 auto parts stores and then about 5 different hardware stores for that 6 gauge wire but its done so I am certainly happen about that, probably could have had the truck all buttoned up and squared away about 2 hours earlier if it were not for the wild goose chase I had to go on around town. Overall this truck is starting to give me emotionally abusive Ex treatment if you know what I mean haha, but seriously let me know if I will be fine with the starter I just put on or if I should try to exchange that one for a different one thank you!

.
Generally the starter that requires a smack with a hammer has a dead spot on the armature or maybe the bearings are worn. You might take it apart and lightly sand the armature to clean it up. That might bring it back to life... Or not. Where did it come from? Straight off the truck, or was it laying around? If it got rained on, it might just be crud on the armature.

.

 

[WWRD99]

Well...having a starter not turning over without a light smack isn't a big deal. That's not really a wiring 24 volt issue. Swap out the solenoid contacts and it should be fine. I'll have to look up which one I use. Have you replaced the starter relay yet?
On another note what did you need 6 guage wire for to fix the glow plugs? How did you wire the relay?

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[Blastercanon1]

I used 6 gauge wire for the Glow plug relay and routed it from the glow plug relay to the front battery post to supply the 12 volts required to power the glow plugs. I have not replaced the starter relay I stopped by Boyce equipment and got a used one from out in their yard so condition unknown as far as how "new" this starter truly is. I know Boyce has a ton of parts everywhere but I am not sure if this one came off a truck or one of their core engines etc. but they did say when I called to see if they had any used ones already taken off they said they would have to go pull one off a motor so could go either way. I still have the old starter and I may just try to make one good starter out of two.

 

[WWRD99]

I used 6 gauge wire for the Glow plug relay and routed it from the glow plug relay to the front battery post to supply the 12 volts required to power the glow plugs. I have not replaced the starter relay I stopped by Boyce equipment and got a used one from out in their yard so condition unknown as far as how "new" this starter truly is. I know Boyce has a ton of parts everywhere but I am not sure if this one came off a truck or one of their core engines etc. but they did say when I called to see if they had any used ones already taken off they said they would have to go pull one off a motor so could go either way. I still have the old starter and I may just try to make one good starter out of two.

Nice!! The wiring for the glow plug relay could have been easier...the output wire on the resistor can be removed and installed on the 12 volt bar. It keeps the original fusible link. No need to add a wire.
As far as the solenoid goes, I bought a 12 volt one for a stock 6.2 and took the contacts out of it and put them in the 24 volt one. I found the contact bolt that sticks out of the solenoid laying on my bench. I tried to file it flat, at the time, then realized that won't work since it will tilt the contactor. You can see how the brass is worn in a half moon on both sides....which shows this one was already apart and turned. If you have only one half moon you can spin it so that side hits the contactor and be done. If mine wasn't spun yet, I would have and that's it. My son is the installer though, so if it were me laying on the ground installing it, I would replace all the contacts in the solenoid. He's gotta learn somehow. The bolt looks like it won't come out but it will...it has a square wire wrapped around it the will pop off with a pick. Big thing now is cold...gotta keep those batteries charged up all the time. That's the Achilles heel of the 24 volt system is when the volts go down the amps go up so far the 24 volt system components melt from the rise in amps. The other is the starter front bracket...without it you will break a starter bolt or block.

 

[Blastercanon1]

I think that I may redo my work on it and utilize the fusible link and thankfully I still have it, you don’t think that that wire above will have a problem with the draw? Also what does this bracket for the starter look like because i definitely don’t remember having one and or seeing it on the truck anywhere under there. So Iam going to definitely make sure I find one because that is one thing I do not want to do is dig those out if they break.

 

[Barrman]

Here is a video about the starters, brackets and bolts:

You need the bracket. Don’t try starting the engine again until you have the proper one installed! Yes, that sounds over dramatic. I have 2 blocks that have the outside screw hole broken off. The block just cracks off out there. I got those engines for nothing because they were useless. I brazed one of them up to work again and used the other for internal parts. Put the proper bracket on!

 

[Blastercanon1]

Here is a video about the starters, brackets and bolts:

You need the bracket. Don’t try starting the engine again until you have the proper one installed! Yes, that sounds over dramatic. I have 2 blocks that have the outside screw hole broken off. The block just cracks off out there. I got those engines for nothing because they were useless. I brazed one of them up to work again and used the other for internal parts. Put the proper bracket on!

Oh man that is actually terrifying I definitely was not running around with a bracket the whole time I have owned it so I will count myself as lucky for sure, I am fairly certain the starter I took off was a gear reduced starter and the one I got from Boyce was for sure the direct drive starter. I still have the gear reduced starter in pieces and I really do not know if it is worth rebuilding as there is very deep scoring and the commutator has melted where the brushes touch. So with that do i see about taking the starter back since I am having some minor problems with it to begin with and try and look for a starter with a gear reduction on it? I bet I could get a starter bracket from Boyce for sure but out of the two styles of starters does it really matter because it appears that I have to chase down a different bracket for the two different starters and just from a quick search online these starters brand new are worth quite the pretty penny. I am really split on what to do at this point as if the gear ruction starter is better and worth the money then I want to do that but also rebuilding the one I have is an option as long as the damage is not too bad but I believe I attached pictures above from when I took it apart so hit me with your opinions on what I should do and anywhere you find is most reasonable for quality parts for the replacement whichever route I go. Thank you