Thanks for all the helpful replies.
I am far from home on my summer cruise
, so need to try things one at a time, avoiding any heavy engineering work which is merely experimental until I can get home.
I think my lift
pump must be with the fuel tank
and between the tank and the Racor
, because it is nowhere to be found in the engine
room. That would mean that I can't trust the vacuum gauge, so gunk clogging the fuel pickup seems to be a candidate. Or a bad lift
pump? Do these things go partially bad? Evidence for this would be the fact that it seems to get worse after heavy motion. Evidence against is that the other users of diesel
fuel on board (genset, central heating) don't have any symptoms. More evidence against: the Racors are spotless. But I'm due for a tank cleaning
anyway (last time three years ago), so maybe I can find a tank cleaning service
around here somewhere. It would be a relatively easy elimination of one thing. Maybe I can get a look at the pickup while it's being done.
I don't think it can possibly be the mixing elbow, because a clogged mixing elbow is not an intermittent fault. But because it's an easy fix, why not pull it off and have a look? Think I'll do that today. Wouldn't hurt in any case to give it a good cleanout. Good suggestion; thanks for that.
I'm think after contemplating that oil
I saw oozing out of the compressor
side of the turbocharger that maybe really it's the turbo. If the seals
are blown, it means the bearings could be getting starved or contaminated with exhaust
gas. Now that could be an intermittent fault -- bearings don't run smoothly so drags the turbo down, sometimes more, sometimes less. Evidence for: turbo doesn't whistle like it is supposed to. Oil
oozing out, which can't be normal. Against: will not rev without a load (although revs more than with one).
When I open the throttle, especially if the engine has not been running for a long time, it will rev up over 3000, then fall back down. What the h*ll? That's not really consistent with any theories so far. This eliminates throttle cable (I've checked that anyway). Do diesel
engine governors go bad? Could it be that? I've never heard of such a fault, but then I am not experienced with diesel engines.