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Post by terravistawombat on Dec 7, 2006 17:10:15 GMT 11
Hi. I purchased a 1992 MU 2.8 t/deisel 3 weeks ago. From start to about 10 minutes everything is fine, but after 10 minutes, after downhill runs with no accelerator, sharp stopping or hard corners, I lose power and pour dark smoke for a while, then it clears up. Deisel mechanic thinks this may be due to a low charging alternator (waiting for caryard to replace) but as it seems to be intermittant, this may be wrong. All vacuum pipes seem to be fitted, but was wondering if a crack or bad fitting vacuum line could cause this problem.
Any help greatly appreciated. Cheers.
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Post by geeves on Dec 7, 2006 19:19:30 GMT 11
Everything is controled by the vacume pump on the back of the alternator so possible. Low charge would cause no problems till the battery gets to 7.8 volts Then you walk home. Bad vacume lines are possible but I would not be optomistic. If the smokes blue and smelly bad rings come to mind. If its black you could be looking at pump,injectors or the only ray of light being the air filter.
Sorry to be bringing for fore telling of doom but it doesnt sound too good
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Post by Graham on Dec 7, 2006 20:31:45 GMT 11
How does your oil pressure gauge read when this happens?
the scenarios of hard cornering / braking make me think that it could be oil surge - the oil in the engine is moving away from the oil pick up. Check the oil level in the engine, make sure it's OK.
As Geeves said, is it blue or black smoke (oil or unburnt fuel)? Someone said that unburnt diesel can sometimes look like oil smoke, though...
Cheers, Graham.
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Post by terravistawombat on Dec 8, 2006 13:00:33 GMT 11
Hi, and thanks for the responses.
The smoke is black, and smells the same as what came out when I picked the MU up from the caryard, when two of the vacuum lines had been reversed by a mechanic. Deisel Australia at Slacks Creek (Bris) swapped them back, and explained that the smoke was resulting from the incorrect vacuum line placement. I contacted the previous owners, and have been assured that the engine was reconditioned 8 months ago, and the fuel pump was exchanged since then.
I havn't looked at the oil pressure gauge while the smoke has been happening, I've been trying to hide from embarrasment, but wiil check this. Engine oil level seems fine, and it's not overly hard stopping or cornering that causes it, but it seems worse depending on length of idling time.
The alternator gauge shows 10 volts at idle, (around 8 to 9 with A/C on) and 12 to 14 volts under use at higher revs.
Hopefully it is the alternator.
Will let you know.
Onece again, many thanks.
Cheers, Ian
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Post by geeves on Dec 8, 2006 18:15:18 GMT 11
Alternator or battery definatly faulty but causeing this . not sure. If the alternator is faulty the vacume pump might also be faulty so try this first. Next if you still have the EGR fitted check this. then I would be checking the injectors,pump timing (might be loose) turbo/wastegate.
good luck. The description is not oil smoke so it should be fixable.
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Post by Harry on Dec 11, 2006 21:59:38 GMT 11
Have a look at the rod between the wastegate controller and the wastegate lever,under the turbo.If it's oily you've probably split the diaphragm, although you won't be running the same boost as I am.Check out my post in Engine mods.Thinking about ot I'll be running even more boost now with no controller and the over pressure valve blocked off.Have to try and get a bit more fuel in though to take advantage of the extra air.
Harry.
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Post by terravistawombat on Jan 1, 2007 8:55:16 GMT 11
I received the MU back from having the alternator rebuilt, and the smoking has lessened in quantity and frequency, but still needs further study.
It still smokes for around ten to twenty seconds after slowing, coasting, or stop and go's, but at least it has more power while this is happening. Not full power, but at least it moves.
Cheers.
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