Jetdriver69

On my 82 5 speed, if I adjust the warm idle to 750+-150 rpm then the cold idle is quite low @ 600 rpm.

If I adjust the cold idle at 750 then the warm idle is a bit over 1000 rpm.

Right now I am using a happy medium but my warm idle is at the high side of 900 rpm.

Could the air fuel mixture be off? My timing is 25 degrees, so just a 2 degree advance over stock. Maybe a bad cold start injector?

I have no smoke on start up to indicate a rich condition, but the engine has a slight hesitation when revving when cold. The revs increase with throttle input but fall below idle for a half a second before going back to idle.

This condition improves as the engine warms but never completely goes away. I have a new temp II sensor, new O2 sensor and no vacuum leaks. All lines are new and have been smoke checked.

Any suggestions? Thanks!

The Forgotten On

Check the aux air valve located on the back of the spider on the passenger's side.

It could not be working or need an adjustment, there are write ups on this and it is easy to do. If all else fails get a used one from 928 int. as new ones are nla. It costs ~ $50.

A bad cold start valve would make starts hard in the morning as it is only on for less than 7 seconds.

Good luck on fixing the issue.

Jetdriver69

The car starts fine, within 1-2 secs, warm or cold. It is the cold idle that is the problem. I will pull off the valve and check it anyway.

I am down to the annoyance items, the cold idle, radio noise (which I am addressing today) and pulling the pod when it gets cooler to clean up connections and replace the alternator warning bulb assembly.

All the big stuff is done...for a while

The Forgotten On

If it is after 1-2 seconds it is definitely the aux air valve. They are notorious for this issue and usually just need the bimetallic strip bent a little.

Alekseiev

Hi there
928 82 us ljet

I have an issue concerning my idle decreasing on cold start starting at 300rpm to nothing , everything was working fine when the car was previously charged .The idle on cold start was 800rpm , but last night I didn’t charged the car . Today at the startup the idle was decreasing ,near the point of stall . The idle ajustment bolt do nothing to correct that .Is that because of my low voltage ??? I have did an intake refresh , vaccum hose and fuel filter ,pump , hard line, recently. Aux sensor ? Temp sensor ?

thanks to all