Low Idle when Cold (help!)
 

hey guys, well this has been a problem for a long time and is really frustrating!!!

The problem is this: when i start up my 78 924 in the morning it will NOT stay running unless i keep my foot on the accelorator, it will just die.
then the RPM will rise in proportion to the temp of the engine (so it seems) so at normal running temp it will idle at 950 RPM.

When i park the car and leave it for 10 or so minutes and then come back to it, it starts first time but will idle at 200 RMP or so then give it a minute or so and it will go back up.

I also have the classic hot start problem, sometimes when warm starts on 2 then 3 and finally 4 cylinders.

Im thinking it may be a fuel pressure problem or bad injectors.

what do you guys think?

I have replaced:

Fuel pump
Fuel distributor
fuel filter
AAR
WUR
Rubber intakes
coil
rotor
plugs

I know it has nothing to do with my cold start valve because it "starts" after 2 seconds of turning the key, just won't keep running.

:confused:

Any advise much appriciated!

the aux air valve that i replaced was from the wreckers so it may also be faulty?

Minewas doing that sort of thing until I did my yearly service that included removal of intake system and cleaning all electrical plug in things including the leads from the clutch housing and O sensor. Upon reassem ly (spilled coffee on key oard and some letters don't type), the cold idle works properly. So I don't know what I did other than clean all contacts on top of engine.

I would clean your injectors - the 2 then 3 then 4 cylinder startup sounds like leaking injectors. When the engine is off, fuel leaks into the cylinder and floods them. It takes several revolutions to clean out the excess fuel and start firing properly. The exhaust should smell real rich while this is happening. If a cleaning solution doesn't take care of the problem, new injectors may be necessary.

Also, if your car has sat for a long time, the gas could have gone bad or have some water in it. Don't forget that there is a filter in the tank itself (a rather expensive one) in addition to the filter above the transmission.