1985 SE Idle Problems
 

Given the number of past posts dedicated to SE idle problems, I may not be adding anything new. However, after hearing my sad story, maybe somebody can offer some hope.....As background, my SE's hunting and high idle problems have been ongoing for probably close to 6 years. Initially, it was very rare, and I would only have hunting problems after a few hours of driving - it would not necessarily hunt at any particular idle, and I would normally be able to kick it off. On a few rare occasions, I would have to stop the car to get the hunting to stop. Over time, the problem has continued to be intermittent, but more frequent. The frustrating part is that I can drive for a whole weekend, and not have a hunting or high idle (usually stays around 1000-1100 rpm) until the last two hours of the trip. Or it will starting acting up within minutes of driving away. Occasionally, I have started the car and left it to idle, and after a few minutes of warming up, the hunting starts, and then a few minutes later, stops on its own. Very strange. The last thing I have (presumably related to all this) is that in low gear (1,2,3), the car will often surge on its own. For instance, I can keep a steady pedal at 3000 rpm in 2nd, and the car will surge "down" and then back up on its own, with the tach reading never having changed. It means for jerky driving.

I should note that the general performance of the car has not been affected by these gremlins e.g. acceleration and mileage.

I have done the following checks:

- Throttle chamber cleaned. Plates seem to be opening and closing fine.
- No leak at lower intake manifold gasket
- No apparent vacuum hose leaks
- Linkage checked and lubricated. Seems OK.
- BAC/ASV taken apart and cleaned. Nothing amiss there.
- TPS checked OK. Has been replaced before.
- All Emission checks from manual check out OK e.g. afterburn valve, switching solenoid valve, relief solenoid valve, split air solenoid valve, ignition control, purge valve, and fuel cut operation.
- Dashpot and vacuum control solenoid valve OK.
- While in place, ASV and BAC appear OK, altho I need to do battery power checks on the vent solenoid valve and vacuum solenoid valve.
- Adjusted idle down to 800 RPM. Was at about 900 RPM.

The only thing that seems suspect from my checks is the Air Control Valve. The book says air is supposed to blow out of it when above a 1500 RPM. It only does it when you accelerate the engine, and it usually gives you a "exhaust spit" noise. No air comes out when the throttle is held high and steady. Is this normal? And for the second part of the checks, when the split air hose and vacuum sensing tube are disconnected, air is supposed to flow from the latter tube's port. It does, but it is weak. Could this Secondary Air Control System have anything to do with it (e.g. air control valve)??

A long story, but it may bring back "fond" memories for some of you. Does anybody have any ideas? I would like to keep the 12 years of fun with this car to carry on. Thanks.

Palmerston.