2004 LLZ Duramax glow plug failure

[merritt racing engines]

I have a 04 Duramax the glow plug light stays on seen on this forum it might be the controller replaced it still have the problem.
Is there a fuse inline some where?
Any ideas?:confused:

[More Power]

The wait to start light stays on?

Does it power the glow plugs while the light is on?

A Tech II scan tool can be used to test the system.

Jim

[merritt racing engines]

Dropped it off at the dealer today I will soon find out.

[merritt racing engines]

It was the glow plug control module.
Also found a burnt glow plug and a bad injector in number 6 cylinders.
Does the LLY Duramax have a problem with eating glow plugs?
Did a bad injector take the glow plug out?

[DmaxMaverick]

A bad injector can cause a failed glow plug. It depends much on what is bad about the injector. If a cylinder is constantly overfueled, excessive heat can cause premature failure. The GP's are generally reliable, but do fail from time to time. I've had 4 GP's fail in my LB7, and I attribute the failure to the injector failures. I don't think it was just coincidence the cylinders with failed GP's just happen to also be the "problem injector" cylinders. They're not too costly, and easy to replace, so it's a minor issue as far as I'm concerned. When they fail, they do so quietly w/o mechanical damage or difficult removal, unlike the 9G plugs in a 6.2L.

[OC_DMAX]

I have read a number of Duramax posts where failed glow plugs "snapped off" when mechanics went to remove them. The entire cylinder head had to be removed. The repair went from being fairly simple and inexpensive to costly.

[merritt racing engines]

Thanks they had to order the injector it will be in after the holidays.
will it hurt the truck if I run it til then?

[DmaxMaverick]

It depends on why the injector is bad. Did the dealer say? Results can vary from no harm to a redesigned piston. If it's just over/under fueling, you can go easy with it unless it is really overfueled, but you'd hear that knock. If the bad injector is the same hole as the bad glow plug, I wouldn't drive it unless absolutely necessary, and certainly would not tow, haul or flog it.

[merritt racing engines]

Thanks for the head's up!

[Kennedy]

Thanks they had to order the injector it will be in after the holidays.
will it hurt the truck if I run it til then?

That would/could be like running a gas engine with a fouled spark plug. I wouldn't do it if I had a choice.

[woods]

Can Anybody Tell Me Were I Can Find The Glow Plugs On A 2004 Duramax?????

[DmaxMaverick]

Welcome to the Forums!

They are on the outboard side of the head, just above the exhaust manifold.

[woods]

Thank-you For Your Answer On The Location. Now What Is The Best Way Of Changing The Number One Glow Plug Since This Is The Third Time I've Had It At The Dealer In Two Years. No More Warrenty. I'm Sure Its Going To To Get Expencive.

[DmaxMaverick]

Remove the passenger side front wheel (not necessary, but makes access easier). Remove the plastic fender liner, or the front half of it and bend it out of the way. Push the IC (intercooler) pipe aside just enough to access the plug. Disconnect the plug. Remove the plug, just like you would a spark plug. Install the new plug and finish up in reverse order.

If you have one plug continually failing, you need to find out why. Is this a LLY or LB7 engine? The 8th digit of your VIN is the indicator (besides obvious engine differences). 1 is LB7, 2 is LLY. The LLY has the injectors outside the valve cover, while the LB7 has them under the valve cover. A couple things can cause GP failure. A bad injector is one of them. If you are having GP's fail randomly (not the same cylinder), then it's a control or voltage problem. Or, it could just be time for them to fail. Some last forever, others aren't as long lasting. If you are using a power programmer of any type, it could be causing higher combustion temps, which can shorten the life of a GP. Hard to say w/o getting "hands on".