Ok boys, 1999 Dodge 3/4 ton diesel

We ( not me) bought this pickup from another University and it ran well for a week or two, then started having trouble. I sent it in the have the tranny flushed out and it helped some. Then this truck started loosing power. Turn the key off and it will again run like a striped ape

Black smoke means rich... hmmm. I'm not specifically familar with the exact model or anything but if it occurs randomly perhaps check the MAF stuff and or see if there's anything that could be partially blocking the intake or airbox like leaves or a rubber boot or a folded splashguard.

Could be a great many things... intermittent electronic problems are the devil incarnate... maybe try a hi-perf truck shop as opposed to a dealer and ask some advice. It's bound to have happened for someone else too.

Cheers,

Vic

Check the oil level in your engine.

If it's overfilled this can get into the combustion chambers and seeing as diesel is an oil, the glow plugs will ignite the engine oil and cause the running on effect.
Similarly, keep an eye on the oil level as you might have worn valve stem seals or piston rings. That would let oil in too.

Will also raise the engine revs as there is no control over engine oil being burnt.

but this does not explain why putting your foot down will give you 3k revs yet only a slow speed.

The black smoke is mostly soot. All diesels cough up black smoke at some point, particularly on start up. You might have a faulty exhaust system. Check for blowing or damage, like a crushed/blocked section.

Back pressure in exhausts is as important as letting the gasses escape. Too much back pressure and the engine chokes.

Try changing your glow plugs. They might need replacing.

The high revs/low speed is a bit odd. I assume you've got an automatic box.
It could be the catalytic convertor rather than the box itself.
It's the same principle as a slipping clutch. You could have all the revs you like, but with a worn clutch/convetor, you're only going to go so fast.

edit to add; just had a thought.. have you got one of those gear boxes that you can select high or low gears (as used in some 4x4 vehicles like land rovers) aside from the main gears?

Might be stuck in low if you have.

[edit on 26-1-2008 by Extralien]

Well I think it's an electrical gadget of some kind.

Maybe the throttle sensor? Hell, it may have chewed up another injector pump.

Roper

It could be the TPS... or the injectors are getting a full stroke message when they shouldn't. That it revs but doesn't upshift or pull is likely electronics. Maybe write Dodge or Cummins... I'm not sure of your particular exact combo. For sure it's weird. Maybe have a look at the TPS and whatever plenum and see if it has any coke or varnish build up.

You shoud be able to get the pump, ecu, and injectors tested somehow off the vehicle. I've seen it done for 18 wheelers. Quite interesting to see a gummy injector spurt compared to a fresh laser cut re-man.

There's gotta be a diesel specialty shop. I know Gale Banks is doin' Dodges... give them a ring or an email?

Cheers,

Vic

EDIT to add: dodgeram.org...

My buddy Tommi says hey, and to snaffle a Clymer and a multimeter and hunt for bad/intermittent grounds on the fuel system devices as well.

[edit on 27-1-2008 by V Kaminski]

Roger that V Kaminski and tell Tommi thanks. I'll ask them if they did this stuff.

Roper

Hey, no problem. U2U me or post and let me know what it turns out to be. The idea of what you described has me scratching my head. It's like full fuel and not enough air... but the part where you mat-it and it winds up but doesn't go... well that's just gonzo? Hey does it engine brake normally when you get out of the throttle with no brakes applied?

Try dragging the brake a bit when it happens again see if the motor cleans out (less chug-smoke).

Nice trucks tho', the full size. Good haulers.

Vic

[edit on 27-1-2008 by V Kaminski]