New Glow Plugs Installed; Starts Worse Than Ever

[gottaluvit]

Ok. I got this truck a couple months back and when the seller was showing me how it starts, he said it needed glow plugs before winter. When it started before, I always had to crank, stop, turn key off, crank again and it usually started (sometimes took a third attempt). After starting, there was relay clicking sounds (usually three off and on cycles) and the volt meter would move from yellow to green and vice-versa on each click of the relays until it was done and meter was in green. Today I changed the wellman glow plugs that were in it for A.C. Delco 13Gs. Now it takes seven or more crank attempts to start. Oh yeah, last time I started it right before dark, it started at high rpms for a second or two and reaked of unburnt fuel. I only do about three second cranks of the starter. Question is, why on earth would it be worse with brand new glow plugs?

P.S. There was this in the glove box when I got the truck.

 

[cucvrus]

Do you have a test light and voltmeter?

 

[gottaluvit]

Yes sir.

 

[cucvrus]

See if you are getting voltage thru the relay at the master cylinder. It should be the bottom side hot when the wait light is on. Of course the top side is always hot. Hot meaning positive current.

 

[gottaluvit]

I ran out of daylight, but will check voltage at each glow plug connector tomorrow. So strange how new plugs made it worse.

 

[gottaluvit]

See if you are getting voltage thru the relay at the master cylinder. It should be the bottom side hot when the wait light is on. Of course the top side is always hot. Hot meaning positive current.

Ok. I will check that. I have good understanding of electricity but ignorant to diesels.

 

[cucvrus]

I think it has an intermittent glow plug relay. The rev of the engine was all the fuel that was being put into the cylinders while you were cranking it and it was not starting. Like a flooded gas engine. Check it out and get a picture of the engine. the ballast is a black rectangular box on the firewall directly behind the air cleaner. it has a wire going in from the bus bar positive side and a wire coming out and going to the relay. If someone was not hacking away at it. From what you said about the volt meter cycling after starting I think it is still wired as original. Which is fine with the 13 G glow plugs. That is all I ever use. Never had any serious side effects with that combination.These pictures show the ballast resistor on the firewall.
I removed it and replaced the wire to the relay because someone had cut it off. It also was hard to start and had 6 spent wellman glow plugs. This is the Jersey Indian M1028 that i am showing you. it came here for repairs and I am currently doing repairs to it.

 

[tim292stro]

See if you are getting voltage thru the relay at the master cylinder. It should be the bottom side hot when the wait light is on. Of course the top side is always hot. Hot meaning positive current.

And reply with what voltage you see on the "always hot" side when the key is off....

The ballast resistors of a 24V glow system are located in a bracket on the firewall directly behind the air filter housing:


If those are missing, and you're measuring 12V at the relay, the resistors have been bypassed. If there are NOT missing, and you measure 24V at the relay with the ignition off, and again with the ignition on during your "wait" cycle - if that measures above 12V you have a blown plug.

 

[gottaluvit]

CUCVRUS: thank you for your help and the pics. I remember seeing that black thing behind the air cleaner because it had me wondering what is hiding behind it. The solenoid looks brand new on mine. I hope it isn't all homerigged. I will post some pics tomorrow and some voltmeter results

 

[cucvrus]

Either way it is an easy fix if you choose to do so. Just remove the resistors with the 3 1/4" 3/8" headed hex bolts. and it the wire is missing replace it if you choose. it is 10 gauge wire. I used red and crimped new eye ends on each end. Hooked it all back up and it starts and runs as designed. I like the cycling in the morning. if your belts squeal tighten them or replace them. If you let them squeal the squeals will only get worse as winter rolls around. Good Luck.

 

[gottaluvit]

And reply with what voltage you see on the "always hot" side when the key is off....

The ballast resistors of a 24V glow system are located in a bracket on the firewall directly behind the air filter housing:
View attachment 594414

If those are missing, and you're measuring 12V at the relay, the resistors have been bypassed. If there are NOT missing, and you measure 24V at the relay with the ignition off, and again with the ignition on during your "wait" cycle - if that measures above 12V you have a blown plug.

What do you mean by "blown plug"? Glow plug?

 

[gottaluvit]

View attachment 594435View attachment 594434View attachment 594433View attachment 594436View attachment 594437View attachment 594438Either way it is an easy fix if you choose to do so. Just remove the resistors with the 3 1/4" 3/8" headed hex bolts. and it the wire is missing replace it if you choose. it is 10 gauge wire. I used red and crimped new eye ends on each end. Hooked it all back up and it starts and runs as designed. I like the cycling in the morning. if your belts squeal tighten them or replace them. If you let them squeal the squeals will only get worse as winter rolls around. Good Luck.

Hmm. No thanks button, so "thanks"! Looks like some beefy resistors and I will rewire mine if fingers have gotten to butchering. I like stuff stock, as their engineers hopefully knew more than the farmer I got the truck from.

 

[tim292stro]

Yup - when they fail they stop heating, sometimes they fail swollen and need to be removed with some extra grunt work, sometimes the tips break off and fall in the cylinders.

...if the wire is missing replace it if you choose. It is 10 gauge wire. I used red and crimped new eye ends on each end. Hooked it all back up and it starts and runs as designed. I like the cycling in the morning. if your belts squeal tighten them or replace them. If you let them squeal the squeals will only get worse as winter rolls around. Good Luck.

Make sure you check the resistors before putting them back in a circuit if they were removed by a previous owner - there may be a reason they were cut-out. The ballast resistors can fail two ways in general:

• Open - annoying because the remaining resistor will only allow half the current to pass to the glow plugs (and they will REALLY have trouble with their job).
• Shorted - dangerous, it'll either let too much power to the plugs burning them out extremely quickly (a day or two or even less depending on how bad the short its) - OR it'll short to ground and burn out the fusible link (hopefully before it sets the truck on fire).

There is trouble shooting stuff for these in the TMs.

 

[cucvrus]

9 chances out of 10 someone just cut the wire because they read that was the BBD. bigger better deal. I only ever had one bank of the resistors fail in all my years of driving them. I bought every one of the resistors I could get my hands on thinking they were going to be a problem. Now I just have a big crate full of complete resistors. Never needed another one. And the one that failed was on an M1010 that was charging at 36 volts + when it happened. I have an M1009 Crown of thorns that is charging at 36 volts I just drove it to work today. And the only thing that I noticed is the dash lights are very bright and the Sony kicks off because of the over charge. I am thinking it is the left alternator. I don't think I would see it in the dash lights from the right alternator. I will get the volt meter out later and check. I never heard of a truck burning up because of the ballast's shorting. I know they get hot they are designed for heat. Live and learn or NOT. Just never seen or heard of it till now.

 

[tim292stro]

Not so much ballast resistors I worry about as fusible links. if you keep the resistors clean there's really nothing to catch fire (unless you like to keep your engine compartment clean and shiny with a judicious application of WD-40 or 15W40).

 

[gottaluvit]

Tim292stro and cucvrus, you both have the solenoid wired in differently. Mine has the resistors and is as cucvrus's pic shows having the wire from the resistors to the top sol. post. I have 24v at that post. With the key on there is 24v at the bottom post but is going back and forth to 0v with the relay clicking off and on, which it didnt do before the glow plug switchout. Time now to check voltage at each glow plug wire and then pull each plug to see if they work. They were new old stock off ebay and looked new but had purple ring which I assumed meant GM tested each one. I might have gotten scammed!

 

[Skinny]

I like stuff stock, as their engineers hopefully knew more than the farmer I got the truck from.

I agree but sometimes they have to make systems a compromise to meet a design or work with the technology they have. The GP bypass simply works for 99% of the people out there and eliminates a major failure point. The M1009/1008/1031 charging system is not a bad system even though some people are scared by it. There really is no reason to be. The M1010 charging system has a lot to be desired so most modify it so that it works the way it should of when new.

 

[tim292stro]

So you do have ballast resistors if you see 24V unswitched at the solenoid.

Well 24V at the switched side (glow plug side) of the glow plug relay tells me you may not have any functioning glow plugs any more. That would make it a bear to start. I did a post on what you would see with a cascade failure of the glow plugs here. Basically if you look at the bottom of that post you will see some voltages I calculated you would see with various counts of burned up plugs.

Before we say "aw nuts" and buy a whole new set of plugs, let's take a look at the rest of the glow plug circuit - yes, you want to verify that there is continuity from the switched side of the glow plug relay to each glow plug connector. You want to do this with a load that will pull some decent power though. Do you have a 24V light anywhere (like an armor light or something)? We want to pull more than 50 Watts over that glow plug wire - and when you measure at where the wire meets the light, it should be no more than 1V lower than what it is at the relay.

If you have a bad wire or two or more, and you replace your glow plugs with new, they will just burn out again quickly. If you really don't want to go through the debugging of the glow harness, you can just run new wires to each glow plug and back to the relay - use 14 Gauge or thicker wire to each glow plug.

Again, you should still verify the resistors are good - there is a troubleshooting guide in the TM (can't recall what age off the top of my head) but IIRC each one should measure out to about 180 milliohms or 90 milliohms in parallel. See previous post for the things that can happen with a bad resistor.

 

[gottaluvit]

Well, I just tested every wire to the glow plugs and every one had the correct voltage. So I went to pull one of the new 13Gs and it wont come out. All but two wont come out. Tested the two with jumper cables on 24v and nothing on them two that came out. Tested one of the wellman's that I took out and it glowed immediately. All the wellmans came out easy with no swelling. I guess my next dry day with daylight time is the joy of getting them garbage 13Gs out. Why on earth did GM not make a removable threaded sleeve that could simply be replaced if the glow plugs did swell to the point of nonremoval. I agree on not much brain function of the day

 

[tim292stro]

If all of the glow plugs were not type/brand matched that's probably what did the others in.

They all need to have the same electrical characteristics or the ones with the lowest resistance will burn the hottest. Do you know what model the Wellmans were?