well, it ended up being a faulty waste gate solenoid.... dealer replaced it and now truck runs great... thanks for everyones help j
forgot, would a pmd or pump explain the large amount of black smoke too..? >
>
> > The first thing to do is change the fuel filter and drain any water out of
> > the seperator. What you describe really doesn't sound entirely like a fuel
> > related problem, but the filter is an easy and relatively inexpensive thing > > to do.
> >
> > Second, does your Service Engine Soon light come on? If it does, you're
> > going to have to get the codes pulled from your computer. At 75,000 miles
> > (and provided no significant modifications have been made to your motor),
> > you should be about due for an FSD (fuel solenoid driver). This is the back
> > box attached to the driver's side of the fuel injection pump that controls
> > the fuel delivery solenoid. In their stock location, heat will kill them at
> > about the mileage you are at. At best all you will need is a new FSD
> > (sometimes called a PMD or pump mounted driver - same thing). At worst the
> > heat from the FSD will have ruined your optical sensor and fried your pump,
> > in which case an entirely new pump is required. Cost will be (hold on to
> > your hat) between $1300.00 and $1800.00 for a new fuel injection pump,
> > installed. And yes, the dealer will be at the higher end of the range. But
> > there is good news! Your truck should still be covered under the special
> > waranty extension that GM gave all owners of 6.5L turbo diesels (it lasts
> > through either 110,000 or 120,000 miles, I don't remember exactly how far).
> > Contact your dealer and see what they can do for you - provided it is
> > actually your FI pump and/or FSD after all.
> >
> > If you do have your FI pump replaced, the next step is to prevent if from
> > happening again. Check out this link
> >
formatting link
for some interesting reading> > on this problem and the solution. You can also do a search for "FSD Cooler"> > to find retailers who deal in these coolers. This is definitely one of the> > most worthwhile investments you will ever make for your motor.> >
> > Good luck - Jonathan
> > --
> > Acta Non Verba - Deeds Not Words
> > Lieutenant Jonathan Race, EMS Supervisor
> > Orange County (FL) Fire-Rescue Department
> >
> > > i recently bought a 97 GMC Yukon, 75K miles. when i first start the
> > > truck it has plenty of power and just a little grey smoke under heavy
> > > acceleration. once it gets warm though the power drops off and i get
> > > heavy black smoke under acceleration and it seems to have a flat spot.
> > > i have replace the air filter, the temp. sensor, used diesel
> > > additives, removed the cat. the problem seems to be worse when i run
> > > the a/c, but that may be just because of the higher ambient temp. when
> > > the a/c is on. any ideas on the problem or ways to troubleshoot. ? > > >
> > > thanks
> > > j
> > >