Finally bought a Dmax

[Putzboy]

And man do I love it!!

Picked up an '02 Chevy, crew cab, short box, 4WD with Allison, LS trim level. Truck was very well taken care of and from the looks of the undercarriage, was strictly highway driven (100K miles). FUll maintenance records as well, everything done by the book. Even has a sprayed in bed liner and upgraded rims with 285 tires.

Only problem it has is the dreaded P0380 glow plug error. So, what is the easiest way to replace these things? I'm thinking from the fender, by removing the inner fender panel. I can see a few of them, but getting there from the top looks next to impossible. Any tips would be greatly appreciated.

I've got an AFE intake on the way and will most likely be ordering my 4" exhaust by the end of the week.

Also picked up a spare ECM and I'm going to try my hand at tuning via EFILive.

Love the site, I have been reading until my vision goes blurry. LOL

Ken

[DmaxMaverick]

Glow plugs are a snap. The best access is through the wheel well, with the inner liner removed. You can get to some from above pretty easy, so you better check for the bad plug first. The GP controller (because you have a CA truck--Fed's are different) has two connectors on top, toward the rear. Check out the "truck stuff pics" link in my sig. for a pic of it. The connectors are left/left and right/right, and are in order. You can check for the bad plug by unplugging the connector on the controller, and check them for contiuity to ground. A test light or VOM will work fine. The open circuit will be the bad plug(s). Each plug has its own wire into the connector. Also, if you have a scanner that will read PCM parameters, the GP voltage will tell you how many plugs are out. And.... if you find no plugs failed, the intake heater element shares the same code, so it could be fried.

I don't recommend replacing all of the plugs. Buy 2 or 3, and replace them as they go. The truck will start and run fine until you get around to replacing, except for that annoying SES light. Mine's staring at me again for the same reason, and I'll get around to it sooner or later. No hurry.

[Putzboy]

OK, I had found a thread earlier that described the testing of the glow plugs at the controller. I did that and found that 4 of them are bad. I hooked a test light to positive on the battery and hit each one, seems as though I only have one good plug on one of the banks.

I ordered an entire set of the instant heat plugs last night. Depending on the difficulty level, I may just replace the bad ones. The PO said he replaced all of them before, but who knows how long ago that was or what plugs he used.

Just bought the Digimoto scanning software too, used it last night for the first time. I didn't find a parameter in there for reading specific voltages from the GP, but it may be programmable.

Thanks for the response, I look forward to many happy years with my new truck.

[DmaxMaverick]

If you have 4 bad plugs, and they have been replaced recently, I'd suspect another graemlin at work somewhere. These GP's are generally reliable, and moreso than previous engine designs. Unlike the 6.5/6.2 GP/WTS light, the Duramax will show the light one time, and only before start, even if the plugs are heated afterward. You need to monitor the voltage during running to make sure they are turning off. If you don't have a scanner that can monitor the voltage, you can install a light powered by one of the plug harness leads. Once the engine gets slightly warmed up (a minute or two after start when very cold), the GP's should not be on at all.

The plug you should be using is GM part # 97226202. You can not use the LLY plugs on your LB7. Using a different, or "instant heat" plug could explain the short life.