Thread: Isuzu 4bd1 smoke

This engine often gives a bit of smoke but you've already looked at the first thing - partly blocked aircleaner. Any restriction to the intake will cause this - at least some of them have a guard element in the aircleaner, and this may need changing as well.
Other possible causes could be the injection timing slightly out, or loss of compression, although in that case you would expect loss of power and hard starting. At that mileage it should only be just about run in, but even a short time with leaky intake in dusty conditions will cause a lot of wear.
John

yep...what jd said....
black smoke.....sounds like its running rich.....get it tuned.....
you need to adjust the pump timing......


maybe get the injectors serviced and check flow rate and make sure they are not dribblng....

Black smoke is over fueling, this can be a benifit (more fuel more power) and a problem (to much and you wash the bores of the lube properties ie oil) white smoke and yes you will see it a/cleaner/snorkel blocked ect or not getting enough air.

Thanks for the tips. Do you think the fact that it has been running at 65 degrees would have caused premature wear? Think my next step is to get the compression tested. Then proceed to the injectors.

Originally Posted by wovenrovings

Thanks for the tips. Do you think the fact that it has been running at 65 degrees would have caused premature wear? Think my next step is to get the compression tested. Then proceed to the injectors.

Cool running will accelerate wear, but not by that much. If it starts easily and runs smoothly (well, they all vibrate pretty badly when idling, but you know what I mean - evenly) it is unlikely there is much wrong with the compression. Before taking the injectors out, I would check the timing and see if that fixes the problem. Not too long after I got mine, I got the injectors overhauled for the same reason as you - and got them back with a nice big bill, and the news that they did not need attention, so I wasted my money (can't remember how much - that was about twelve years ago).

It starts easily so i will check the timing. It has some blue smoke on startup and as they have valve stem seals i wondered it they could be the primary cause of that. (205000km since '84 it must have done a lot of sitting and them could have gone hard). The primary reason i know it blows more that it should is I can see it in the rear view mirror (angled down) at anymore than normal power. In a mates 86 wagon nothing at all is visible in the mirror except at full power. Is it cheaper to get the injectors checked (for dribbling etc) as opposed to cleaned?

Originally Posted by wovenrovings

It starts easily so i will check the timing. It has some blue smoke on startup and as they have valve stem seals i wondered it they could be the primary cause of that. (205000km since '84 it must have done a lot of sitting and them could have gone hard). The primary reason i know it blows more that it should is I can see it in the rear view mirror (angled down) at anymore than normal power. In a mates 86 wagon nothing at all is visible in the mirror except at full power. Is it cheaper to get the injectors checked (for dribbling etc) as opposed to cleaned?

I think you will find that either cleaning or checking will involve stripping them down, and once you do that costs are going to be about the same. Try to find a good diesel service outfit locally - there should be some about there, and mostly they will advise you on this sort of problem.
John

Originally Posted by wovenrovings

It has some blue smoke on startup and as they have valve stem seals i wondered it they could be the primary cause of that. (205000km since '84 it must have done a lot of sitting and them could have gone hard).

If it was sucking engine oil down past the valve stem seals, you'd have the terrifying experience of a runaway engine, that is, the engine revs like mad as the engine oil is being burnt as fuel. The only to stop it is to wait until all the engine oil is gone and the engine seizes! Does your engine want to continue running when you turn off the key?