I am having a problem with my 82' 3L CIS motor. When it's fully warmed up. (Oil is at 200deg or better) It likes to idle up on it's own.. If I leave the car in nuetral and blip the gas the engine will stick at 2000rpm on the way back down. If I drag it down with the clutch it will Idle at 1000rpm for a quite a while. This only happens when its warm. When cool it's crisp and always comes right back down..

I've done the obvious. New manifold boots etc... Could it be the warm up regulator? I am not running the 02 sensor either..

Ohh, it also does something else I think is strange. When Idling, I'll open the oil tank to check the level the rpm drops to ~600 and barely stays running. If I replace the cap idle comes back up to 1k...

What the he!!?

 

wild *** guess, when it warms up the ECU switches to closed loop. W/O the OX sensor the feedback voltage may be the problem. The ECU is somewhat smart and Idon't now if there is a quiescent operating point with the OX sensor leads flying in the breeze. What happens if you put the OX sensor back in the loop or just short out the OX sensor leads and see what happens to the idle.

 

their is a vacume valve on the back of the cis manifold I think its called the auxilary air valve or something. when the engine decelerates it opens to allow air into the manifold so that their is not excessive vacume in the manifold, this could be the cause of you problem to check this take it out and plug the hoses and run the car and see if it makes a difference. it could also be the mechanical advance weights in your distributor sticking causing the ignition timing to be advance and raise the idle. to check this put a timing light on and check for proper advance curve and make sure the weights are returning. when you take the oilcap of and the engine idle drops means you are starting to have excessive oil blowby by the rings. this will make a lot of vapor in the oil tank that gets sucked in the motor though the hose going from the tank to the airbox. this vapor richens the idle mixture and the engine sort of runs on that at idle. when you take the cap off the vapor go into the atmosphere and the idle mixture leans out and the idle drops. do a copression and leakdown test to check if you rings are worn. Anymore questions??