2003 Duramax is not accelerating

[mscott107]

Hey guys just found this board, Hope you can help as my dealer is clueless and wants to shotgun parts.
Heres the problem:
Truck just had a bath and also under the hood due to the fact that she was covered in mud from the ranch roads that my girl friend drives on to go to work. Now she hops in it a couple hours later to go to the mall and on the highway she said she could not get the truck to accelerate. So I checked it out and what it is doing is it seems as if all off the boost from the turbo is being dumped, it will accelerate to a point and when it down shifts it just hangs there. You can see some black smoke from the exhaust; I want to say it acts like a governor almost. I have check all the connections on the harness for water and everything is dry, any help would be greatly appreciated as I would hate to have the dealer just start shot gunning parts on my wallets behalf.
Scott......

[markrinker]

Connections can appear dry from the outside, but still have enough moisture inside them to cause problems.

I would spray exposed electrical connections with WD-40. It dispells the water and only leaves behind minimal residue. (Keep it off the serpentine belt smile.gif )

If that doesn't cure it, I'd look for anything disconnected by the high pressure washing.

[Kennedy]

Fuel filter is first to mind, but also if you have a fast idle/PTO installed, it could be armed and cause this. That and MAF sensor could be fouled. As Mark stated, harnesses can hold water if it gets into the connectors, but I've washed mine underhood without issue.

Here's how to check fuel filter:

http://www.kennedydiesel.com/detail.cfm?ID=289