Varying idle speed with 1hz motor - what can cause it? (1 Viewer)

[sunrk]

Is anyone aware of what can cause the idle speed of a 1hz to vary away from the 'screw setting' on the injector pump? I've got mine wound up a little (I set it to 700) because of the rough idling issue, but sometimes it'll idle up to 800 rpm. I haven't get done anything with injectors (got a full set of new ones plus seats) or checking the pump timing. Current pump and injectors were all reco units fitted about 6 yrs ago.

The 1hz is the original motor fitted 26 yrs ago to the vehicle so it's old/tired.

 

[mudgudgeon]

Do a search here for "rough idle" and "dash pot".

May not be your problem, but worth a look

 

[roscoFJ73]

Something to do with the governor and/or the dash pot. They are somehow connected from memory. Is it something to do with the aircon fast idle up by any chance?

 

[sunrk]

AC doesn't work in my 80 - it has the 'single dealer option' config of AC but never worked since I go the 80 in 2011. There is the idle-up dashpot present but it never does anything. Some of the wiring for the AC in the engine bay is damaged/missing and I've had no desire to fit it.

I now have a genuine tool to adjust/measure the IP timing so might have a go at checking that. Some people say that as IP's wear their timing advances - I don't know how far out of spec the IP timing can go before it's a problem.