12ht rough idle

[cjman1966]

i reccently put a rebuilt 12ht in my 60 series cruiser,it runs well lots of power had a full rebuild except for the injector pump,which runs fine and i was told the 12ht pump is rare to have problems..my dramer is when the motor is cold first thing in the morning,idles fine runs fine,when it gets to operating temperature the idle becomes rough,but still goes well,blows a bit of smoke under load only.all vaccum lines are connected except two that go to some sensor in the oil cooler , so why does it run so fine cold but not when it hot?????????? any ideas i will gladly reply to...thanx

[oldmate]

They have a cold start idle-up. THere's a screw on the back of the pump for adjusting the idle. Check it when warm. Should be 650rpm for a manual transmission, 770rpm for auto

[BadMav]

Just some ideas to throw at you... Check everything is tight, glow plugs, injectors, manifold bolts/nuts etc. I would go as far as re-torquing the head bolts. Has the timing been set and checked? Also check it's not using any water either, if it is, it could be a hairline crack or split head gasket letting water in somewhere it's not meant to be.

[cjman1966]

thanx for that will get the timing checked this week,and the idle is a little high if thats the case,and it is a manual

[lc61vx]

That sensor thing in the oil cooler is actually your BVSV valve.. vacuum from here runs to the injector pump which controls your idle (cold/warm)... i'd say, connect the vacuum lines to this valve and to the injector pump for starters.