tired of this annoying idle surge

[93whitelaserrs]

I replaced the isc once and it didn't help any, so I checked the plugin and it read between the ohms it should, I had another isc so I took the old on off again and hooked up a 6 volt battery to it and the new one also, the new one seemed to virbate more then the old one so I but it on, idle surge still there. I read some more about them, I found that 4 out of 5 cases had been the o-ring on the idle screw on top of the throttle body instead of the isc so I replaced it but still there. is there any thing that I'm missing that could be the problem.

 

[chaclark83]

Ive had the same problem. Today my car idles at 1500 yesterday it was between 400 and700. Stil have no clue what is causing. Dealer told me once that the 2nd gen computers will fry if the IAC goes bad causing permenant damage.

 

[1g4g63pwr]

I replaced the isc once and it didn't help any, so I checked the plugin and it read between the ohms it should, I had another isc so I took the old on off again and hooked up a 6 volt battery to it and the new one also, the new one seemed to virbate more then the old one so I but it on, idle surge still there. I read some more about them, I found that 4 out of 5 cases had been the o-ring on the idle screw on top of the throttle body instead of the isc so I replaced it but still there. is there any thing that I'm missing that could be the problem.

When you mean by new , do you mean dealer new or junk yard new?

 

[93whitelaserrs]

junkyard new, why makes no difference

 

[boostedinaz]

Dealer told me once that the 2nd gen computers will fry if the IAC goes bad causing permenant damage.

I have never heard of that and it seems a bit ridiculous.

junkyard new, why makes no difference

If they are bad from the get go and you put it on then it would seem to make a big difference. If they tested ok and you have tried a few then I would say it is the FIAV. After time they can go bad and it will cause a surge. I was trying to find a page that showed how to block of that part, but it seems to be down. If you search for FIAV block off you will find how to make the plate.

 

[femmeDSM]

I have never heard of that and it seems a bit ridiculous.

I know that on 1gs at least, if the coils on the ISC are blown, it will blow the ISC drivers on the ECU, which will definitely cause "permanent damage" (i.e. a smoking ECU )

Maybe that's what they were referring to.....

 

[turboholic]

http://www.dsm.org/how-tos/tttt/tttt3.html

 

[boostedinaz]

I know that on 1gs at least, if the coils on the ISC are blown, it will blow the ISC drivers on the ECU, which will definitely cause "permanent damage" (i.e. a smoking ECU )

Maybe that's what they were referring to.....

Interesting. I have had a few bad ISC's but never a blown one.

 

[femmeDSM]

Interesting. I have had a few bad ISC's but never a blown one.

Yeah, same here. I don't know how common it is -- the only reason I even know about it is because I had to hear all about it from the guy I bought my GSX from....Apparently, he went out one morning, started the car, and the ECU "caught on fire" as he put it... ...I think that's one of the reasons he ended up selling the car, actually. Haha. Oh well, it's in better hands now, anyway

I've had a couple of ISCs fail the "6v battery test" but all the ones I've tested have ohmed out within specs. Fingers crossed, anyway.

Apparently, when those coils go, they take out the ECU drivers pretty quick. If I remember correctly, the drivers it kills are IC105 and IC107 (Steve? Correct me if I'm wrong.) At any rate, they are the black drivers near the top/right of the board.



anyway...back on topic. .

 

[chaclark83]

Mine actually fried the IAC circuit in the board.

 

[fastlaser90]

Where exactly is isc located? I'm thinking it may be causing my car to idle like crap.

 

[femmeDSM]

Where exactly is isc located? I'm thinking it may be causing my car to idle like crap.

On a 1990, the ISC is located on the bottom front of the throttle body. It's a little round gold-colored motor. Hard to miss

 

[fastlaser90]

My Isc tested out fine so I decided to spray some carb spray around the intake manifold gasket for kicks. Surprise!!! My idle start jumping up and down immediately so I guess I've found at least one of my problems(theres always something).