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04 LLY starts/restarts fine then shake rattle n roll check lite on

dduramax

32' Colorado 5th 2004 pure stock does it all
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Location
west coast
140k km been great until today started fine ran fine downhill for 5-10 min. Then started noisy clatter and no power check engine lite came on restarted quietly only to go into limp mode 5 minutes later. fuel filter is recent air filter clean have limped home and need to read code clues???
 
You limped the engine. ECM is turning off pre-injection so you get the genuine full diesel rattle. It will have a code.

Couple things that trigger this would be air in fuel from leaks. Primer seal failures, filter head cracks, plugged fuel filter, gasoline or water in fuel, Wix "plastic krap body" fuel filter leaking air at WIF thread area.

The other would be loss of connection to an injector. look up the "ICE PICK trick" to fix the injector connectors. http://www.duramaxforum.com/forum/h...how-ice-pick-injector-harness-connectors.html
 
Look at the main harness that goes over the alternator. There were many LLYs that had a short develop from rub through there.
Thanks guys
checked for rub nothing apparent
I reprimed the filter - it seemed full at first "pump" I picked up another filter tonight so will give it a try on the weekend
 
My bet is you have a poor connection at either injector 2 or 7. When you lose the connection to 1 injector, the ficm shuts off the voltage to 4 injectors. It powers the injectors in 2 blocks of 4, and grounds the injector to activate it. The FICM outputs 48 volts for an lly, and 48 volts is enough to arc and cause all kinds of issues if the circuit is left open, so as a safety it kills the entire group. So that leaves you with 4 cylinders running, hence no power, and the 4 cylinders dead pumping make the exhaust obnoxious.

The only time I know of that the ECM kills pilot in the programming is when the main injection fuel rate drops below roughly 2.5mm3 of fuel. Many times excess engine noise results from high rail pressure. Pilot is still active, but due to the extremely high rail pressure, the injection pulse width is so reduced, cylinder pressures spike from the increased injection pressure, and clatter clatter clatter even though pilot is still there.

The harness rub issue by the alternator normally results in blown fuses and a no start. Without codes though, it's all guesses. Based off of what you've posted, I would get a can of electrical contact cleaner, spray out the plugs of injectors 2 & 7(front drivers side and rear passenger side), and do the ice pick fix(google lly ice pick, you'll find MANY results).
 
Thanks for what sounds like the most applicable scenario of what I am observing. After I clean 8" of fresh British Columbia snow off of truck I will check those two connections. I did have a serpentine belt and idler pulley go this summer - with no "apparent damage" but this may be a late result of the bits flying around at the time.....
 
I just down loaded Codes 01/03 PO202 p
02/03 P2149 03/03 PO202 p

this seems to confirm an issue with the #2 injector connection
has anyone found a pigtail with a female and a male end rather than splicing in one end only??
 
Does the code have to be cleared or is it informational only?
You can leave the codes in there but I think the SES lamp will continue to illuminate. Most people record the P0 numbers then clear them.
They`ll probably continue to come back until the problem is fixed.
 
Like Ferman mentioned, Google ice pick fix and you'll find plenty of help making that repair. And yes, I would clear the codes although after the repair and with enough key cycles they should clear.
 
You should clear them, but I'm pretty sure the lamp will go out so long as the code is not active and it has made 3 consecutive drive cycles without an error. GM sells an updated end. Simply adding in a plug in pigtail would keep the problem plug in the system defeati,g the purpose of the fix. I personnally don't like the ice pick fix. I prefer to take the pins out 1at a time, clean them, tighten them, then put them back together, but the ice pick fix is proven, and is a simple diy correction.
 
Success!! Thanks for all the feedback. Cleaned the "dusty" offending #2 injector plug code cleared and truck is running great. New replacements are on the way to make it good permanently. Fix will be 20 bucks courtesy of Amazon supplier.
 
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