"Stump the Dummy"

[MaxACL]

This is a game we would play on long flights but this time it's my truck.

After idling for 2 to 3 minutes (while waiting for a long light to change or making a phone call) my DuraMax will smoke like a mosquito fogger for about 15 to 20 seconds when I accelerate then it clears up. No degradation in performance, it just smokes. A little history: I have had several codes for EGR valve, Glow plugs, Glow plug controller, Boro Something, Cam sensor, a Partridge and a Pear Tree. The GMC dealer did a test ($100) and confirmed these. I drove to my farm in East Texas (200 miles) and had doubts about making it. The engine would progressively buck till it got so bad I had to stop.
I would re-prime the filter several times and it would work fine for about 10 miles then that wouldn

[jbplock]

White smoke at idle is a symptom of failing injectors .. Did your mechanic check the injector balance rates?

[Gnostic_1973]

I agree white smoke at idle is typically due to unburnt fuel, which can be indicative of an injector leaking. The dealer should be able to check this easily with a Tech 2. They will just need to check the flow rates, not the balance. The balance rates are a correction factor that uses the crank sensor and previous fuel injection pulse. If the injector is going bad it will show higher fuel flow rates and the dealer can determine this quickly, so give them a call.

[jbplock]

Appreciate you insight and comments ... It was also my understanding that while not the best test, high injector balance rates can be an indicator of injector problems as the ECM attempts to maintain idle by adjusting the amount of fuel to each cylinder. Here's a snip from a GM TSB ...

"...Customer concern may be … white smoke at idle, or high positive injector balance rates… High positive injector balance rates (over +4.0 in park or +6.0 in drive) may be causing white smoke at idle or while driving …"

:)

[More Power]

Everyone agrees... :) Injectors... I'd want to get this taken care of soon, because a leaking injector could result in a holed piston. :(

Jim