khdutch

My 1990 S2 has been off the road for the last 4 years. Now that I am available to use it again, I can't get it to idle properly. First I should say that I replaced the water pump and all the belts and everything is back together ok. The idle hunts about 1000 RPM and keeps stalling and it appears to be running very rich. I suspect something on the motor is stuck or has failed probably due to the long storage. Can anyone suggest what to look for or replace? (It was doing this before the pump and belts were done also.)

porscharu

Fuel pressure regulator would be where I start.

931guru

Check your plug wires.

beamishnz

Check no leaks/cracks in rubber fittings on inlet side of MAF. Cracked rubber boots are common and confuse the engine management.

Tom Pultz

I would 2nd this recommendation. My S2 had periods when it wouldn't idle and also periods when it would barely run and was belching allot. With a new fuel pressure regulator it runs like new.

V2Rocket

oxygen sensor going bad will cause idle to fluctuate and car to run rich.

jhowell371

Fuel pressure regulator failure caused mine to take a bit of cranking to fire up. It was leaking into the vacuum line and running rich and rough on start up. When the 02 sensor went it would barely run.

Tom Pultz

I checked my records, and when I had the fuel pressure regulator replaced (along with fuel filter and pump), I also had the throttle position sensor replaced, which is most likely the fix for the intermittent failure to idle. P/N was 0 280 120 308.

djantlive

How old is the gas?

plumbum

Could be so many things but I would start with parts that were touched when the belts were changed...plug wires, vacuum hoses intake tubes ext

porscharu

It is frustrating when someone posts a problem, and never updates with the fix. It doesn't help anyone in the future searching for the same issue. So then they post a thread, and get several suggestions without updating. It is common courtesy to the community that helped you solve your problem. Not preaching to the OP, but have ran into this several times when researching.