| OK... the algae thing is definitely something to look into here. The truck sat for a little over 3 months before I bought it.
My mechanic did another computer scan yesterday. He said all the return rates looked good on the injectors. He also said that fuel system pressure and flow looked pretty good, and that he wasn't sure why the dealer thought that was out of whack. He thought that sound was kind of hollow... almost like a lifter collapsed or something, but we thought that a collapsed lifter would also make noise at an idle, not just under accelleration... and I don't know how a sloppy lifter would make the little bit of white smoke I am seeing either. Again, my mechanic is really good, but he doesn't have a ton of experience with the duramax's, so he's really not sure what to think.
Is it possible that there is some algae crud growing somewhere on the engine side of the filter causing flow to be restricted to just a portion of the fuel system? Maybe just one injector? Enough maybe to cause some injector noise but not enough to throw a flashing ses light?
Oh yeah... he got out his "car doctor stethoscope" and listened to each injector individually as I power braked the engine to put it under just enough load to generate the tapping/knocking. He said the injectors all sounded the same... and that he couldn't hear anything right under the valve covers that would suggest a rocker arm either... we just don't know where the sound is coming from. I would like to say it's just a normal sound, but even the tech at the dealer said it wasn't right... of course, they tried to hose me on the egr stuff too sooooo....... who knows.
thanks for your patience here on the forum trying to figure out a noise for me that you can't even hear. I know it's a long shot, but I am learning alot about this engine.
thanks again
-duane |