The same glow plug constantly roasting mystery..

[Retiredwarhorses]

I’ve responded to this on FB…this is quite simple to TS, pull the GP lead and run the truck as normal, if you aren’t getting a melted GP?
you now know it’s your EESS box is the issue, IMO it’s the box…your GP timer is stuck on and 24v is present after 9 second.
i suspect all the other GP’s are also bad as well now, looking at the picture tell me that plug experienced longer than 9 seconds of voltage, I see this often…have you yet checked for voltage after 9 seconds and the GP wait lamp expired?

 

[Humpty]

I’ve responded to this on FB…this is quite simple to TS, pull the GP lead and run the truck as normal, if you aren’t getting a melted GP?
you now know it’s your EESS box is the issue, IMO it’s the box…your GP timer is stuck on and 24v is present after 9 second.
i suspect all the other GP’s are also bad as well now, looking at the picture tell me that plug experienced longer than 9 seconds of voltage, I see this often…have you yet checked for voltage after 9 seconds and the GP wait lamp expired?

I have put a meter on the lead. 24v is NOT present after the initial warmup cycle. It was one of the very first things I did. I stated that right from the get go.

This is the FOURTH failure of the glowplug in this cylinder. No other glow plugs are so much as swollen.

 

[Humpty]

I dunno... I seem to be smart enough to check glow plug leads before changing injectors 3 times, but that's just me...

I DID check the glow plug lead. I replaced the original injectors just because I had no idea how old they were and was going to replace them anyway. I replaced the second set because everybody and their cousin swears the import injectors are crap.. yet i’ll still have people chiming in about it being the injector.. or the glow plug voltage.. despite having put an actual meter on it and verified its not overcycling.

 

[Humpty]

I’ve responded to this on FB…this is quite simple to TS, pull the GP lead and run the truck as normal, if you aren’t getting a melted GP?
you now know it’s your EESS box is the issue, IMO it’s the box…your GP timer is stuck on and 24v is present after 9 second.
i suspect all the other GP’s are also bad as well now, looking at the picture tell me that plug experienced longer than 9 seconds of voltage, I see this often…have you yet checked for voltage after 9 seconds and the GP wait lamp expired?

Here’s the glow plug from the ajacent cylinder.. it was installed when I replaced all the glow plugs last year. I’ve also included a pic of a brand new glow plug for comparison. All the other glow plugs look the same as this. If the controller were overcycling to the extent it was incinerating glowplugs.. enough to roast the same glowplug position FOUR times in a row.. ceartinly these cheap ass Amazon glowplugs would be at least a little swollen or something wouldn’t they? Instead all the other glow plugs basically look new and meanwhile just one cylinder keeps roasting glow plugs.

 

[Mullaney]

Here’s the glow plug from the ajacent cylinder.. it was installed when I replaced all the glow plugs last year. I’ve also included a pic of a brand new glow plug for comparison. All the other glow plugs look the same as this. If the controller were overcycling to the extent it was incinerating glowplugs.. enough to roast the same glowplug position FOUR times in a row.. ceartinly these cheap ass Amazon glowplugs would be at least a little swollen or something wouldn’t they? Instead all the other glow plugs basically look new and meanwhile just one cylinder keeps roasting glow plugs.

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Maybe you have a leaky injector that is dribbling onto that glow plug...
Seems like somebody might have mentioned that on here before.

 

[Coug]

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Maybe you have a leaky injector that is dribbling onto that glow plug...
Seems like somebody might have mentioned that on here before.

reading the whole thread, he's replaced the injector multiple times and still has it happening

 

[Humpty]

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Maybe you have a leaky injector that is dribbling onto that glow plug...
Seems like somebody might have mentioned that on here before.

They did. Several people did. That’s why I replaced the injectors to begin with. Then I replaced them again because people said the import injectors I used were junk. Still having the problem with Delphi injectors so its safe to rule out the injectors. I ordered a diesel compression gauge and it’ll be here Wednesday. I suspect what i’ll find out is i have low compression on that cylinder and thats resulting in incomplete combustion of fuel. That fuel ends up coating the glow plug and is igniting during the glow plug heat cycling and that’s what’s roasting my glow plug.

 

[Mullaney]

They did. Several people did. That’s why I replaced the injectors to begin with. Then I replaced them again because people said the import injectors I used were junk. Still having the problem with Delphi injectors so its safe to rule out the injectors. I ordered a diesel compression gauge and it’ll be here Wednesday. I suspect what i’ll find out is i have low compression on that cylinder and thats resulting in incomplete combustion of fuel. That fuel ends up coating the glow plug and is igniting during the glow plug heat cycling and that’s what’s roasting my glow plug.

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Well... That would suck. But at least you are on a path.

So, I guess you will be shopping for a replacement power plant if the reading comes back way below the other cylinders? Might even be worth looking at a @Mogman post about his installation of his "DuraVee".

How not to install a Duramax in a M998

Well hopefully this will not be the epitaph for this project, I thought a thread with the progress and possible pitfalls that lay ahead might be interesting to someone, constructive criticism, hints and comments from actual experience will be of course welcome. Some of this has been told before...

steelsoldiers.com

 

[Retiredwarhorses]

You said these are cheap amazon Glow plugs, Have you metered all the other glow plugs to verify they are actually good?
I’ve seen these cheap GP’s look fine….but are dead as dead comes, no swelling, no nothing.
looks are not a test…using the meter is the standard.

 

[Humpty]

You said these are cheap amazon Glow plugs, Have you metered all the other glow plugs to verify they are actually good?
I’ve seen these cheap GP’s look fine….but are dead as dead comes, no swelling, no nothing.
looks are not a test…using the meter is the standard.

Starting easy in -27 degrees suggests they are probably warming up. Watching the meter on the dash pulse shortly after starting to complete the warm up cycle indicates they are drawing current. I have had no reason to suspect they don’t work beyond this paranoia about import parts people seem to have.. but for the sake of standard, they meter just fine.

 

[Humpty]

.
Well... That would suck. But at least you are on a path.

So, I guess you will be shopping for a replacement power plant if the reading comes back way below the other cylinders? Might even be worth looking at a @Mogman post about his installation of his "DuraVee".

How not to install a Duramax in a M998

Well hopefully this will not be the epitaph for this project, I thought a thread with the progress and possible pitfalls that lay ahead might be interesting to someone, constructive criticism, hints and comments from actual experience will be of course welcome. Some of this has been told before...

steelsoldiers.com

No blowby at the dipstick or oil filler and no bubbling or nastiness at the radiator or overflow tank suggests to me if my compression is low that it’s likely a valve not closing all the way. Might just be gummed up. It runs and drives alright and had enough compression to blow two of the glow plug guts out so my hope is I’ll take off the intake and look down at the valves on that cylinder and they’ll just be mucked up. I’ll clean the hell out of them with a non abrasive brush and see what happens. If no joy there.. then i guess the next step would be pulling the head. Swapping out the powerplant seems like a pretty drastic measure.

 

[87cr250r]

If you have a junk glow plug that failed and you keep replacing it with junk glow plugs and they keep failing have you ever considered that it may be the junk glow plugs that are the problem? If you don't want to buy a full set at least put a good plug (Delphi?) in that hole and see if the problem moves to another hole.

 

[Retiredwarhorses]

Starting easy in -27 degrees suggests they are probably warming up. Watching the meter on the dash pulse shortly after starting to complete the warm up cycle indicates they are drawing current. I have had no reason to suspect they don’t work beyond this paranoia about import parts people seem to have.. but for the sake of standard, they meter just fine.

If you don’t ask, you don’t know….will leave you with it, seems you got it under control.

 

[Humpty]

If you have a junk glow plug that failed and you keep replacing it with junk glow plugs and they keep failing have you ever considered that it may be the junk glow plugs that are the problem? If you don't want to buy a full set at least put a good plug (Delphi?) in that hole and see if the problem moves to another hole.

I hate to break it to you Captain America, but it was a “Made in USA” glow plug it spit out FIRST.

I then replaced ALL the glow plugs. 7 of them have been perfect, it’s this one cylinder that keeps eating them.

Glow plugs are not some high science and these trucks are essentially 1950’s farm tractor technology. You wanna buy into the hype and pay a premium for parts, knock yourself out. In over 20 years of buying parts online, most if them Chinese import parts, I have had ONE failure.. of a coil pack, and that was probably my fault because I didn’t have the air intake assembly put back on right but they still replaced the part at no charge 4 months later.

 

[Retiredwarhorses]

I hate to break it to you Captain America, but it was a “Made in USA” glow plug it spit out FIRST.

I then replaced ALL the glow plugs. 7 of them have been perfect, it’s this one cylinder that keeps eating them.

Glow plugs are not some high science and these trucks are essentially 1950’s farm tractor technology. You wanna buy into the hype and pay a premium for parts, knock yourself out. In over 20 years of buying parts online, most if them Chinese import parts, I have had ONE failure.. of a coil pack, and that was probably my fault because I didn’t have the air intake assembly put back on right but they still replaced the part at no charge 4 months later.

You’re gonna go a long way here buddy…a real Gem

 

[Dieselmeister]

The failed plug in the picture has seen some severe heat. Either too much fuel, or something wrong in the precombustion chamber, directing the detonation towards the plug instead of down into the combustion chamber. Do you have any way to disconnect the fuel line from that injector, and another one, (one at a time), and measuring the fuel quantity for a given amount of time and comparing them? A quick way to check is measuring the exhaust header temperature at each cylinder. A overfueld cylinder would have an hotter exhaust. I would also shove a bore scope down the injector port, and the adjacent injector port, just to get a comparison. Worst case could be a timing problem on the pump, injecting fuel at the wrong time. That's doubtful though, due to the pump design, and it would also show as either a power loss, or increase in that cylinder. My thoughts, and what I would try.

 

[kendelrio]

Have you read the TMs?

 

[Humpty]

The failed plug in the picture has seen some severe heat. Either too much fuel, or something wrong in the precombustion chamber, directing the detonation towards the plug instead of down into the combustion chamber. Do you have any way to disconnect the fuel line from that injector, and another one, (one at a time), and measuring the fuel quantity for a given amount of time and comparing them? A quick way to check is measuring the exhaust header temperature at each cylinder. A overfueld cylinder would have an hotter exhaust. I would also shove a bore scope down the injector port, and the adjacent injector port, just to get a comparison. Worst case could be a timing problem on the pump, injecting fuel at the wrong time. That's doubtful though, due to the pump design, and it would also show as either a power loss, or increase in that cylinder. My thoughts, and what I would try.

Thank you for your perspective. That’s exactly what i’ve been looking for.

That extreme heat is what lead to the leaky injector theory. I have used an infrared thermometer while the engine was running to compare temps between the different cylinders and everything is pretty uniform. I’ve used my bore scope each time its eaten a glow plug just to make sure there weren’t any random hunks of injector rattling around in there and did look at a few others when I was changing injectors for comparison but didn’t see any differences between pre-combustion chambers from cylinder to cylinder. If my compression check ends up being ok it’ll be the fuel side of the equation i’ll look at next. Is it possible the pump could somehow be pushing too much pressure on just one line? I’ve also thought about timing.. but i’d think that if timing was off then ALL cylinders would be off?

For rate of flow, could I just pop the fuel line off and point it in a cheap measuring cup and crank the engine for like 15 seconds?

 

[Humpty]

Have you read the TMs?

Well.. I read THIS one.. it said to send it to some other department. If you could point me in the direction of the TM that covers my issue on the M998 that would be super helpful. There are a TON of TM’s and aren’t particularly well titled.

 

[Mogman]

Considering how the IP operates it is highly unlikely it would deliver more fuel to just one injection line, this would also likely be detectable by a "miss" or knock.
It is also unlikely the harness is delivering more current to one glow plug
with multiple injectors and glow plugs, and inspection of the pre combustion chambers all that could be left would be a compression test.
I would think if that was way off you would have smoke from unburned fuel and an engine miss.
It is also unlikely you have an intermittent stuck valve, basically the only clearance from the piston and the valves is the thickness of the head gasket, it would have to "stick" just a few thousands off of the seat, but I suppose that is slightly possible.
I have to say you have a very strange issue.
If the compression test does not show anything and if it runs well, if it were me I would just stick a new glow plug in and not connect it and enjoy driving the truck, it will start fine on 7 and if it blows up then source a 6.5L GEP the cost compared to the benefits would not be much higher than going into the old 6.2L for repairs.
I am curious about one thing, how did you know it burned up the one glow plug??