Do 3.2's really need an ISV?
 

I have a low idle - maybe 700 or so and not as smooth as it ought to be.

So, I jump the connector in the engine bay elec compartment to take the Idle Stabilization Valve out of operation, in order to adjust my idle speed. Fine - that works well - until I remove the jumper and my idle goes down to where it was.

The question is why I would need the ISV in operation. If I have a steady idle, would it be an issue to keep it jumped and 'out of the loop' ?

thx,
todd
86 coupe

You no crucial reason to have an operational ISV. Its purposes, though, are beneficial for:

1. To maintain a constant idle RPM with varying loads, e.g. A.C. , lights on
2. To prevent RPM undershoot on decel
3. To act as a "dashpot" in limiting RPM decel for emissions
4. To help with starting, i.e. no need to press lightly on throttle as with carbs

Things to check for a functioning ISV:

1. the throttle switch - pins 2 & 5 of DME, must be 0 ohms with throttle at rest
2. the pins of the ISV - 20 ohms from center to each outer pin
3. center pin of ISV connector @ +12 volts
4. pins 33 & 34 of DME providing good signals

Have you checked the O2 Sensor? Try unplugging it, ajusting your idle and see if the idle problems go away.

Thanks guys. I have checked the idle switch and it is ok. I'll check out the other items this weekend; and if that doesn't work I'll try it out of the loop. The low idle way well due to a leak, though I can't find one. The major sensors are ~10K old.

thx
todd
86 coupe