Cummins 8.3ltr Engine Stalls

[Todd Brunner]

I'm out on my first real trip in my new to me 1994 33' Patriot with the Cummins 8.3ltr 250hp. Three different times I have best traveling ~65mph for an extended period of time and pulled off the road and brought the RV to a stop and the engine dies. The problem is that it is difficult to restart and smells strongly of sulfur when it finally does. If I slow down gradually through the gears it doesn't die. Any information would be greatly appreciated.

[Edward Buker]

There are two things that can stop a diesel that is in mechanically good shape, lack of fuel or lack of air. The easiest to check is if there is any obstruction in the air path. It is more usual that these things affect a diesel under load more than at idle. I would change the air filter to rule it out. So if not the air restriction then fuel filters is the next easiest thing to rule out as a possible cause. There is usually a fuel shut off solenoid in the system you could also check the voltage on that while at idle to see if it is as it should be.

After these checks it is probably time to see a shop about possible injection system problems. You should watch your exhaust as you come to a stop and see if it is exhausting smoke and what color that is as it dies. When it restarts what does the exhaust look like may be some help to the mechanics.

Later Ed

[Dick Simonis]

This symptom of the engine dying when stopping normally but not if you downshift manually sounds suspiciously like the torque converter is not unlocking.  I would have that happen on a Chevy Blazer after I installed a manual TC lock switch if I forgot it was locked before stopping.

[Todd Brunner]

Thank you for the replies. I just had it serviced ~1k miles ago and they replaced the air and fuel filters. At what point does the oil pressure shut the engine off? I noticed that it will drop to ~20psi when it goes to idle. It runs ~60psi at 65mph.

[Gerald Farris]

Todd,
Since your engine does not have an electronically controlled fuel injection system, there should be not oil pressure cut off. However, 20 PSI oil pressure at idle for a hot engine is normal.

Gerald