Strange new noise with my 02

[qinlet]

I have the 02 Duramax/Allison crewcab long bed and was pulling my 12K 5th wheel down to texas and of course in a rain storm when a very loud metallic rapping sound came from my engine. it was like the rapidity of a machine gun. I instantly thought I had lost all my oil and pulled aff at an exit. In the rain I checked my oil and it was good and i did not see any broken parts anywhere. since I was in the middle of Arkansas at a off ramp going to no where I decided to try to limp to the next exit. I started the engine and it ran fine, no noise. to make a long story short it happened 3 more times in texas and always in the rain. I would stop and shut the engine off for a few minutes and everything was ok. The noise never came back in dry conditions, i am sure the rain was just a coincidence. I went to a dealer in Texas since I have heard of injector problems and He told me that he cant do anything unless the engine is making noise. I should have been ready when he asked me if I bought the truck from them because when I said no I could see the get lost look on his face. i have not heard the noise in two weeks so have not been able to take the truck back to the dealer. I may have to wait until I get back to wisconsin. If it is an injector will it hurt anything besides making me go deaf.

[More Power]

Are you running any aftermarket power adders?

Jim

[qinlet]

Yes I have a Edge EZ running at the lowest power setting

[SoTxPollock]

I too have had similiar sounds, but I've never considered it too loud that I thought of shuting it down. I attribute it to the pilot injection shutting off, which is not supposed to happen until around 2650 rpm as I recall. The interesting thing for me is the last time I went through a rain storm I had the front grill cover on and it didn't do that, which suggests to me that some moisture is gathering on some wiring connection somewhere on the Edge and causing it to falsely signal the ECM to turn the pilot injection off. At least that's my guess for now, because it sets no codes. Interesting. I've wondered if saran wrap would stand up to the underhood temperatures, I've thought about wraping the connectors in it to keep water off them that probably gets in there during heavy downpours while driving. I wonder if that might help, if I my assumption is correct?

[qinlet]

that is a good idea. I never thought moisture would get that far back on the top of the engine but it could. And yes every time I had the problem it was raining and I was pulling a heavy load. A fresh set of eyes can usually see the problem. thanks again.