Steam Enginin' It

[MrEdd]

Is this a common problem for everyone else with a 6.5? About 95% of my driving is clean, but the other 5% could put a Cummins at full throttle to shame. My dad thinks it's a leaky injector or one sticking open. What the truck does though, is if I give it gas during those times, it seems like its sticking in a high gear and accelerates very slowly, but absolutely CHUGS thick black smoke. Could it be the computer? We just replaced the PCM with a fender mounted cooler-ed one, so we don't think that's the problem. It's also been doing it the whole time, new PCM and old.

[gmctd]

Check your vacuum pump and tubing system, including wastegate solenoid - no turbo = black smoke and no power

25" at idle and 2000rpm at pump

15" at idle at wastegate actuator

[damork]

I had the same issue on my 95 which has an S VIN engine. It turned out to be a missing EGR gasket that fits between the turbo inlet plenum to intake manifold. If the gasket was never installed or is missing for any reason, you will not have a problem with smoke until you really get on it. Mine was left out when GM replaced the first injection pump.

To check, remove the turbo plenum hose, 4 bolts holding it to the intake, the EGR valve, and any wires from the sensors. It's a simple round crush type gasket if I recall correctly and it prevents EGR gases from entering the intake from the EGR feed. It sits in the center hole of the intake manifold and centers on the hole with an inner ID lip. Some choose to install engine block plugs to permanently seal it off, or switch to an F series intake which does not have EGR. Intake manifold gaskets also seal off the EGR passages from what I understand.

The little round gasket is not that expensive - probably under $5. Worked for me, cleaned up the smoke and performance improved.

[gmctd]

Yep -that's more than likely the case if the upper plenum was removed to do the remote-mounted FSD\PMD.