New M1008 Project

[bwilson7990]

Okay yeah we've definitely got a few plugs that aren't working because the manual glow plug circuit was not blowing a 40A fuse. Probably an answer to why she struggled to start in the cold sometimes.

So if I was to do as you suggested tim/antennaclimber, I would:

1) Connect a large gage wire (0 or 2?) to the battery directly
2) Fuse it with a 100-120A fuse (assuming I am using 8 new AC60G's)
3) Connect the fused hot to the relay on #30 prong
4) Connect outgoing large gage wire coming from relay #87 prong to orange leads to glow plugs
5) Connect ground #85 prong through momentary switch
6) Connect ignition supply to #86 prong on relay

Keeping the 100-120A current on this circuit in mind, will the OEM relay do the job? It's one of those NAPA big ones like for the DH starter mod.
One last question: what gage wire needs to be run to and through the momentary switch for grounding the relay?

Thanks in advance for the advice. I'm still trying to wrap my head around all of the "industrial sized" electrical stuff here.

 

[Chaski]

http://ww2.justanswer.com/uploads/Micharoe/2009-12-29_200141_86_diesel.gif

You might consider a contoller retrofit if your stock glow control system is a total loss. I have no idea how easily it could be retrofitted to a CUCV, but it may be worth looking at. The system is simple and works well.
The relay/contoller is a AIRTEX / WELLS 1R1332

This was the stock system on the civilian 6.2's. Personally I have a 1982 GMC that had a horrible glow control system that used a controller that threaded into the drivers side head and controlled a solenoid mounted on the fender well. I went to the newer system and have not had a single problem.

 

[tim292stro]

Site was a bit slow, sorry for the late reply...

Okay yeah we've definitely got a few plugs that aren't working because the manual glow plug circuit was not blowing a 40A fuse. Probably an answer to why she struggled to start in the cold sometimes.

I would say most assuredly, YES.

Comments in-line in Yellow:

So if I was to do as you suggested tim/antennaclimber, I would:

1) Connect a large gage wire (0 or 2?) to the battery directly <-- 2 gauge should be fine, it can carry up to 200Amps
2) Fuse it with a 100-120A fuse (assuming I am using 8 new AC60G's) <-- 150Amp fuse here, you want the expected max plus 25% to prevent "nuisance blows" (120Amps x 1.25 = 150Amps) This also helps if you change plugs later with different specs/current-draw.
3) Connect the fused hot to the relay on #30 prong
4) Connect outgoing large gage wire coming from relay #87 prong to orange leads to glow plugs
5) Connect ground #85 prong through momentary switch
6) Connect ignition supply to #86 prong on relay

Keeping the 100-120A current on this circuit in mind, will the OEM relay do the job? It's one of those NAPA big ones like for the DH starter mod...

There are many threads on the correct part number relay to use for the GP relay underhood (GPR109 or ST85 rings a bell) - as you can see 100Amps may be fine, but I really prefer a 200Amp rated, silver plated contact relay. Most of the 100Amp relays are copper alloy only, and with the assured high current at make/break, these contacts will wear out faster than I personally like. YMMV, others have had great success with the 100Amp relays, I like the extra design margin - thinking of it this way: "...If the GP circuit fuse is rated at 150Amps, and the relay contacts are rated at 200Amps, the fuse is still the only weak point in the circuit..." Again, YMMV...

The positive power should be from the ignition circuit (pink or pink/black-stripe - don't recall off the top of my head). There should be a wire under the hood somewhere near the brake booster where the GP relay is supposed to go - if it got cut off, you will have to go harness spelunking. The light blue wire in the same general area should go back to your GP card, this is the wire that when the GP card grounds it, will complete the circuit through your GP relay.

If you're asking about terminal numbers, that tells me you're thinking about using a small Bosch cube-type relay - I've never seen one of these rated for over 50Amps, so that's a no go. A true high current relay like a GPR109 will have two very thick posts for the switched load, and two very small posts for the control coil. IMHO it will be obvious which circuits go where.

From my further reading on this subject in the last few weeks, I can surmise that one of the greatest killers of GP cards, is not removing both battery ground terminals when disconnecting the battery for servicing the vehicle. This will cause back feed through the transistor that controls the GP relay - which energizes the relay using the upper 12V battery that is still connected, burning out plugs by running them until the reverse current eventually burns out the transistor (killing the card). This makes it difficult to trouble shoot as many failures can happen at once due to inexperienced mechanics.

http://ww2.justanswer.com/uploads/Micharoe/2009-12-29_200141_86_diesel.gif

You might consider a controller retrofit if your stock glow control system is a total loss. I have no idea how easily it could be retrofitted to a CUCV, but it may be worth looking at. The system is simple and works well.
The relay/controller is a AIRTEX / WELLS 1R1332

This was the stock system on the civilian 6.2's. Personally I have a 1982 GMC that had a horrible glow control system that used a controller that threaded into the driver's side head and controlled a solenoid mounted on the fender well. I went to the newer system and have not had a single problem.

Before we get into that, let's take a better look at the OP's factory GP system - if we go down the modification path, we here on the site will be less easily able to help troubleshoot in the future, since it will not be a stock CUCV system. I think you can buy a GP card from AntennaClimber for less than what you can buy one of the newer controllers for - so if the card holder under the dash is still there, and at least 2" of wire coming out of the card holder is there - we can probably walk through repairing whatever was done to the truck.

A lot of times these trucks get modified because the previous owner didn't have the time or patience to figure out what was wrong with the stock system - it looks more complicated than it is I swear!!!

 

[Chaski]

Glow Plugs-
Since the glow plugs were already on a manual switch and the glow plug module was completely missing we decided to tear out the oem glow plug harness and resistors. Should we save these resistors for anything? Has anyone ever used them for anything else? How about the temp sensor or the location atop the intake manifold at the firewall where it connects, any aftermarket uses for that? We did save the oem relay for this system because it's heavy duty (appears identical to the doghead starter mod relay) and does still work properly. Lastly- we salvaged a few connections coming from the fuse box that used to connect to this system, specifically the switched hot pink/blk wire that we will use for acc for a radio and the blue hot for the "wait light" which we connected to the push button for the manual glow plug switch. This way the wait light illuminates when the glow plug button is pushed because I hate leaving things connected that serve no purpose. I grounded the pink/blk wire on the wait light to where the ground "tree" is typically found behind the cluster where the 4x4 light would be. (see wait_ground pic)

I was just suggesting an alternative as it was stated that the controller card was missing, and that the stock harness has been pruned, resistor pack removed etc... The civilian style controller and harness plug is about $100.00, and the controller is common parts store item if you need one on the road.

 

[bwilson7990]

Thank you guys for taking the time to spell all of this out...

At this point the entire factory GP wiring system has been removed from the truck and we're looking to put this all back together in a custom/manual configuration. We are on a budget and time schedule to get this done (still a lot of cosmetic and plow work to be done before "winter") so we'd like to try and make this happen by acquiring the least amount of addition items as possible. Note:This is only temporary as we plan to start all over in the spring and make this thing 110% over the summer. I'm looking for at least 100% for now

If you're asking about terminal numbers, that tells me you're thinking about using a small Bosch cube-type relay - I've never seen one of these rated for over 50Amps, so that's a no go.

Correct. However, I was referencing terminal numbers for a cube style relay simply to represent the terminals and their purpose (that's what I'm most familiar with). BUT, the relay I will use is the oem GP relay with the two larger, tall posts, and two smaller posts down low. We are on the same page here. I will be sure to fuse the 2 gage lead connection with a 150A fuse. AND we will be installing 8 new glow plugs (AC60G's)


The other thing that doesn't make much sense to me is why the GP wiring diagram in the -20 manual (attached below) show .8 or 18 gage wire for the entire GP circuit after the resistors and through the relay- including the runs to the glow plugs themselves? This has to be a typo because the ORN-503B and ORN-509B wires are definitely at least 8 or 10 gage. The only wires I believe to be that small are the green fusable link feeds (GRN-509 and GRN 503 THERMO HW) connecting to each of the individual GPs.

Conclusion: I'm going to run 150A fused 2 gage to the relay, an 8 gage to each half of the engine (4 GPs) and retain the oem fusible links for the individual GP leads, ignition to the relay switch connection, and the ground through the momentary switch.

I'll mock this up tonight/tomorrow and I'll post pics when it's done.

 

[bwilson7990]

I was just suggesting an alternative as it was stated that the controller card was missing, and that the stock harness has been pruned, resistor pack removed etc... The civilian style controller and harness plug is about $100.00, and the controller is common parts store item if you need one on the road.

Thank you Chaski, I think this is the move that we are going to make this summer when budgets aren't so tight and time isn't either. I do love the idea of having an automated controller that works properly and fires the glow plugs when they are meant to be fired. Good look with this idea.

 

[tim292stro]

...Conclusion: I'm going to run 150A fused 2 gage to the relay, an 8 gage to each half of the engine (4 GPs) and retain the oem fusible links for the individual GP leads, ignition to the relay switch connection, and the ground through the momentary switch...

Sounds like you have a pretty good recipe here. Just for giggles, I'd use 4-Gauge for each of the banks, and then the fusible links for the plugs. The two gauge power feed has 66,369circular mils of copper - going to 8Gauge (16,509circular mils) is about 1/4" the amount of copper in the cross-section - 5Gauge would be a little shy of half of 2Gauge, so the next step up 4Gauge will give you 41,740circular mils (63% of 2Gauge cross-section). This prevents there from being a wire cross section reduction after the GP relay that if you recall is one of the "rules" for fusing.


You will notice that if you have the ignition-switched power and a grounded toggle switch wire to the GP Relay under the hood, you are only a few circuits short of completely restoring the original GP system for which there are 7 total wires:

1. "Start" detect +12V - tells the GP controller when to post-glow.
2. GP Relay Ground - you have this, triggers the GP relay to activate when grounded.
3. Wait light Ground - activates the Wait To Start light when grounded.
4. Ignition power +12V - you have this, feeds the top of the GP relay and the top of the wait light as well as powering the GP card.
5. GP voltage monitor +12V - you have this, thin orange wire tap on the load-side of the GP relay for telling the GP controller that glow plugs are active and that the voltage is not too low.
6. Ground - you have this, simply put this is the wire that completes the GP controller power circuit and is what the GP controller grounds it's devices to.
7. Temperature sensor - there is a two-wire variable resistance coolant sensor that goes into the driver's side cylinder head, this tells the GP controller how long or if it should glow. The other wire goes to GP controller ground (which you will already have).

I noticed on my M1009 that I have a temperature switch instead of a sensor for that last wire - this is not correct for these controllers, correct is AC Delco 213-52, $25 at Walmart...




So you can see, if you set yourself up for the full restoration now while getting a fully manual system in place you don't have much work left to do - the card holder can be substituted by just soldering wires to the card in a pinch. If you want to make it "serviceable" without the GP card holder, a common/cheap 7-wire plug and receptacle is used for trailers

 

[bwilson7990]

Okay great, this thread is becoming near and dear to my heart as it continues to be filled with incredibly useful information. I will do just that. Now, the one thing that still doesn't add up is the gage indicated on the -20 manual diagrams and how the stuff on my truck is so small. I have like 8-10 gage wire feeding each bank. With everything we discussed here I'll be surprised if any of the glow plugs work at all. I've got to gather some supplies for this so I'm not getting to work on it yet. Had to get the truck in driving order so it could get new rubber mounted this weekend. I'll follow-up once I get around to installing this.

 

[tim292stro]

Remember that I'm sizing wire to good Electrical Engineering practice, GM sized theirs to "good enough to last the warranty period, and be cheap enough to get the contract"

 

[bwilson7990]

Remember that I'm sizing wire to good Electrical Engineering practice, GM sized theirs to "good enough to last the warranty period, and be cheap enough to get the contract"

So it's been quite the chore tracking down some of the materials but I think it'll be worth the effort. Wait until you guys see the girth of this relay I got for my stand alone, momentary switch-controlled GP system. The relay is essentially a PAC-200 battery isolation relay. I'm getting setup to install a 150A fused 2 gage hot from one of the batts to the 200A relay which is being mounted at the factory GP relay location on the firewall. It will feed two 4 gage wires (one for each bank or 4 GPs) to 8 new AC60Gs. I think this will be a pretty solid setup. Looking to work it out this weekend so I'll update with pics and such after the work is done. I still think it's a bit overkill, but I guess better safe than sorry.

 

[cucvrus]

Remember that I'm sizing wire to good Electrical Engineering practice, GM sized theirs to "good enough to last the warranty period, and be cheap enough to get the contract"

WOW then I would say they did a stupendous astronomical job. Because I have a few 1984 model CUCV'S that are still all stock wiring and never even had a battery cable end or glow plug terminal changed on them. Lets see the warranty was 12 months 12,000 miles. So they exceeded the warranty by 31 + years and 100, 0000+ miles on every CUCV I have. Not bad. Lets see that happen on all vehicles.
So good enough for GM in 1984 is still good enough for me in 2016. I realize that everyday they may be living on borrowed time. But my/your life itself has no warranties expressed or implied and we all seem to get by. I don't see many vehicles from the early/mid 80's on the road anymore. I do know that they did something right. If this CUCV was a original 1984 gas engine it would give you a headache just to stand next to it with the throttle shafts on the carburetor and intake leaking raw gas. These are for the most part in excellent condition for the age in comparison. Wiring and all.

 

[tim292stro]

So it's been quite the chore tracking down some of the materials but I think it'll be worth the effort. Wait until you guys see the girth of this relay I got for my stand alone, momentary switch-controlled GP system. The relay is essentially a PAC-200 battery isolation relay. I'm getting setup to install a 150A fused 2 gage hot from one of the batts to the 200A relay which is being mounted at the factory GP relay location on the firewall. It will feed two 4 gage wires (one for each bank or 4 GPs) to 8 new AC60Gs. I think this will be a pretty solid setup. Looking to work it out this weekend so I'll update with pics and such after the work is done. I still think it's a bit overkill, but I guess better safe than sorry.

I do agree it sounds like a solid system (as long as the relay holds out with the cycle count), I prefer having lots of margin in my designs, as there are less failures/quirks later. HOW you do the installation is just as important as the WHAT you install question though. If you don't seal wire terminals to the cable, and don't make sure your grounds and contacts are nice and clean and protected, even a ridiculously overbuilt system will only delay the quirks for a short while (which can be very frustrating). Has to do with doing it right the first time versus doing it right-ish over a longer time.

WOW then I would say they did a stupendous astronomical job. Because I have a few 1984 model CUCV'S that are still all stock wiring and never even had a battery cable end or glow plug terminal changed on them. Lets see the warranty was 12 months 12,000 miles. So they exceeded the warranty by 31 + years and 100, 0000+ miles on every CUCV I have. Not bad. Let's see that happen on all vehicles...

Indeed, and my comment was not intended to take away from what GM accomplished, but rather to identify that trade-offs are/were made and why my numbers were different from factory numbers.