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Old Scout · 06-12-2015, 08:32 PM

How many miles on the engine--could be approaching time for a valve adjustment...

Mike Canter · 06-12-2015, 08:44 PM

That's wouldn't cause black smoke. And the valves probably wouldn't suddenly get out of adjustment. I have had diesels go over 100k miles without needing a valve adjustment.

Miramichi · 06-13-2015, 05:50 AM

IMHO. I know I already answered earlier and questioned your fuel (that could still be the culprit) based on your indication of noticing its colour. I have read a lot here mentioning fuel filters. I have a hard time believing that to be the culprit as clogged fuel filter would counter act producing black smoke.

Black smoke typically is produced due to low air to fuel ratio and burning too rich. Meaning all of the diesel isn't burned off and in turn voila black smoke. Have you checked your air filter? There is an indicator for it. It also wouldn't hurt to throw some injector cleaner into your tank. RV's aren't driven as much as SEMI's and things can get clogged up.

Good luck and let us know!

palehorse89 · 06-13-2015, 06:06 AM

Some reading: Diesel Smoke tells YOU a Story…

Dtwallace · 06-13-2015, 06:39 AM

[QUOTE=Miramichi;. I have a hard time believing that to be the culprit as clogged fuel filter would counter act producing black smoke.

Black smoke typically is produced due to low air to fuel ratio and burning too rich. Meaning all of the diesel isn't burned off and in turn voila black smoke. Have you checked your air filter? There is an indicator for it. It also wouldn't hurt to throw some injector cleaner into your tank. RV's aren't driven as much as SEMI's and things can get clogged up.

I agree mostly, but i have had the occasional rich burn when a cylinder drops out due to a partially clogged fuel filter. I seen this many time on stationary equipment, (generators with mechanical pumps) but not on road vehicles.

I would lean toward the lack of sufficient air to complete the burn. Since you are not having this issue on a constant basis, I'd rule out but not completely, a bad or going bad turbo charger. The only time I've seen a turbo contribute to smoking is when it went completely out, so this may be far fetched.

It was mentioned above an exhaust restriction in the form of your exhaust brake hanging toward the close position. I'm leaning this way because I've seen this one first hand happen on the cat motors. I would pay attention to that possibility and check it out.

JMO
DTW

tricotec · 06-14-2015, 12:14 AM

Quote:

Originally Posted by Old Scout

How many miles on the engine--could be approaching time for a valve adjustment...

45k

Miramichi · 06-15-2015, 07:09 AM

Quote:

Originally Posted by tricotec

45k

Well do let us know. 45k is fairly low mileage for a big Diesel engine really. Again it is hard for anyone to diagnose remotely but chances are it is an adjustment or lack of lube or fuel/air related. If you haven't done anything yet, don't be too concerned it "shouldn't" be a major thing.

Good luck!

tricotec · 06-19-2015, 03:06 PM

Subsequent to my other posts I found that the engine brake is not working. I don't really believe it is stuck in the braking position, but it does not work at all. The RV is headed to a cummins facility on Monday to get this and another issue looked at. I'll keep you posted.

oldguy70 · 06-19-2015, 04:48 PM

I would have said air filter or worn turbo but you said the turbo boost was
normal so I would suspect poor quality of fuel especially that you said happened just after fuelling. Change your fuel filter and cut open and check
it for contamination. If it is clean, it just may be poor quality of fuel and
maybe you can be lucky and when you fill up again it will be fine. You could
get your fuel tested.