Does the 3B diesel usually idle rough as hell? The only reason that i am asking is that I have had to re-weld the exhaust at all the flanges twice, (the pipe, not the welds breaks, pipe isn't even rusted at all) and replace motor mounts once. If you hold the hand throttle just slightly up, it smooths out just fine. I know some cummins diesels are like this too, just want to make sure it's normal and i'm not missing something. Also, i need to find a source for a rebuild kit or at least a gasket set for the fuel pump, it leaks like a bastard.

my 3b idles smooth as.

on the pump, try adjusting the idle up slightly until it smooths out.

How many rpm does it smooth out at? It should work unless it smooths out too high.

It is a common problem on japanese trucks, isuzu, hino etc. If they idle too low, around 400-500rpm they vibrate really bad. I just adjust the idle at the pump up to around 600ish, or until it smooths out.

The 3B can idle rough if it's cold outside.

does it get better when the engine warms up?

mine started rough, and changed glow plugs and it was good

also vibration, check rear engine mount (under gearbox) if you have changed the motor mounts

ALSO:
fuel
you running on straight diesel? how lean are you running on the pump? fuel it up a fraction (dont want it getting too much fuel or heat, without turbo)

turbo it!!

im gunna go with fuel though

best take it to a tuning shop, they can fix it......
shouldnt be that rough, but do idle with some vibrations, as most jap diesels will :confused: :p