eyeball kid

So I have had a persistent idle problem...it did not want to idle when under hood temps got high. Otherwise it was fine. After tracking down a boost leak, the idle went all crappy all the time. The car idled as is it were firing on three cylinders--hot or cold. I jumped the isv as per St. Clarks instructions and car immediately idled beautifully.

I believe that this means the ISV is bad, but since it's nearly 200 bucks, I'd like someone to confirm that I'm not missing something obvious and cheap.

Thanks,

Dan

User 52121

Based on your own troubleshooting step (jumping the diag port) I'd say it sounds like you have a bad ISV.

Bri Bro

Try spraying some WD40 or carb cleaner into the ISV to free up the rotating valve.

eyeball kid

Ah, WD40--sacramental wine to gearheads. Thanks for that suggestion.

odb812

Paragon had rebuilt units for $7x.xx with a $20 core a couple months ago, I didn't see them on their site just now, but I'd call and ask Chuck about a rebuilt unit.

eyeball kid

Nice heads up. Thanks. Will do.

jerome951

Just to be sure it is the ISV, cap the openings where the ISV attaches to the intake system. If it continues to idle smoothly, you can try freeing it up.
I tried to free mine up but that didn't work. I just left the intake holes capped and run without it.

hp18racer

Could be the wire harness too. I'd ohm out the connections to the idle stabilizer plug before doing anything else.

eyeball kid

What should that ohm out to? I'm new to my digital MM...so treat me like a moron. Jerome, I'll cap those points and try that as well. Did you have to take the intake off to cap those points?

Dan

odb812

You don't have to take the intake off to cap the points. Just follow the the hose going into and coming out of the ISV and cap the connections on the intercooler pipe and intake manifold. One is on the intercooler to TB pipe and the other is on the intake manifold. I forget if the one on the manifold is between runners 1 and 2 or 2 and 3, so you'll have to see which one leads to the ISV.

toddk911

What are the pros/cons with just running with the ISV bypassed?

odb812

Without the ISV the car will not idle as smoothly when it is cold. It just lets a little more air bypass the TB at idle.

I had mine disabled for over a year and it wasn't a big problem. In the winter I had to raise my idle so the car would warm up without holding my foot on the gas. In the summer you don't notice much difference.

Messing with the ISV with the intake manifold still on the car is a PITA. Intake manifold gaskets are $1.20 a piece so if you are going to replace or remove the ISV, spend the dough and save yourself a headache. Otherwise, I'd just disable it until I was pulling the intake off to do something else(which is when I replaced mine).

toddk911

Cool!

And the easist way to disable is just cap off the hoses coming off the ISV?

eyeball kid

Anybody know what ohm reading I'm looking for at the plugs?

hp18racer

Disconnect the plug at the DME. Touch your probe ends to the idle actuator pin 3 and DME 33, you should show essentially zero ohms. Same test from idle actuator pin 5 to DME 34. Just as important, idle actuator 3 to DME 34 should show infinite resistance as should idle actuator pin 5 to DME 33. Extend one of the meter probes with a LONG wire helps to reach.