Idle bounce between 200 and 2000....Help

[mpwr99]

I have a 1982 SC and this is now the 3rd time this happens to me and i can not figure out what the heck to do?? Basically this morning I started the car up and it would not idle. The idle would bounce from about 200 to 2000 about 3 times and then stall. What i did was just keep the idle up with my foot at about 1000 and just drove off and jumped on the freeway. Once the car reached its 180 degrees the idle then gets stuck and remains at 2000 flat and will not come down. If you tap the throttle it will raise and again not come down past 2000. Then after driving it about 15-20 miles the damn thing all goes back to normal and idles at its normal 900 -950. I do not even know where to start looking for trouble?? Like I said this is the 3rd time in about 2 months that it has done this and all 3 times have been exactly the same. Any help please.

Thanks

[john walker's workshop]

too rich is the likely cause of the surging. had it on a CO machine lately? take the hose off the decel valve, plug it and see if the idle goes down.

[brd]

Are you having this problem when its particularly cold?
Have you checked the resistance across the pins of the WUR or Warm Up Regulator (think it would be around 27 Ohms).

I had a similar issue with surging and slow to stabilise on an 81 SC engine in cold weather and traced it to no power to WUR or the Aux Air Valve circuit (same circuit).

Or could be a fuel pressure issue from a faulty accumulator - need a pressure tester to check that. Or could be a clogged fuel filter...

This was a great help for me in understanding what everything does:
Auto-Solve Diagnostic Assistance

Good luck!

[mpwr99]

Thanks PRD.

This issue yes is always from a cold start and yes did not happen all summer long if that has anything to do with it. I will check the wur to see if i have power next time this happens i guess.

I dont believe it is a fuel pressure issue i have actually checked that and it is fine. I also dont think it is a mixture issue being that as soon as the car is done having its idle moment the thing runs like a champ!!

Thanks

[crustychief]

Originally Posted by mpwr99

Thanks PRD.

This issue yes is always from a cold start and yes did not happen all summer long if that has anything to do with it. I will check the wur to see if i have power next time this happens i guess.

I dont believe it is a fuel pressure issue i have actually checked that and it is fine. I also dont think it is a mixture issue being that as soon as the car is done having its idle moment the thing runs like a champ!!

Thanks

The WUR changes the mixture to compensate as the engine warms up. I think John Walker is also correct as far as the idle speed not coming down. ...take the hose off the decel valve, plug it and see if the idle goes down... If it returns to normal, you can try to squeeze the decel valve gently and free it up.

[brd]

Sounds like we're getting closer...

Another thing to check is the condition of the vacuum pipes... could be cracked with age and causing an air leak.

[john walker's workshop]

the WUR and aux air regulator get power together from the same source. red w/white stripe wire from the fuel pump relay, through the 14 pin connector in the engine area. the wur would stay rich and the aar would stay open w/out power. eventually, engine heat would affect them somewhat.

[mpwr99]

Thanks John!

I did do some further research this weekend even thought the thing decided to run perfect all weekend and I found that the WUR and the AUX AIR are NOT getting any power. Seems to be the harness that is related to the WUR and the AUX is dead. My fuel pump relay is working fine do you recomend anywhere else i should look??

Thank you.

[jwakil]

Check the Pin 10 on your harness connector at the CD. That is the one that powers the WUR and AUX. Figure out if you are getting power at the male pin. Then you can trace where the power open is occurring. In my case, I had a bad contact at the harness connector pin. I fixed that, but then realized I was getting power at both the ground and power pins at the WUR and AUX!. I ended up cutting the ground wire and running it separately to ground and it worked fine after that.

[mpwr99]

JWAKIL........ Are you saying to check PIN 10 (male) on the 14 PIN connector and see if there is power there?

Thank you.

[mpwr99]

Problem fixed!!!! Pin 10 on the 14 pin connector had no power. I took 14 pin connector apart and cleaned it all up some pins including number 10 were loose and had some build up of dirt from over the years i guess. Anyway put it all back together and working perfect! Tried to follow the 10 pin wire ( red with white stripe) from connector to the front of the car but no idea where it goes...... Anyone have a clue??

[stealthn]

Do you have a picture of the connector?

Bob