isc differences - will it work?

[timm98gst]

i have a bad isc in my 98 gst - it's the stock brown one - i have another one laying around that came with my evo3 engine - it's black and looks to be a bit different - will it fit and work correctly if i try to swap them? thanks for your help

 

[nice97civic]

i swapped a black one that looks exactly like that into my car. for some reason after i put it in, it melted the isc driver on the ecu. i may have done something wrong but my idle is fine now so i dunno what the problem was. just check the new isc motor to make sure its working correctly and you should be fine.

 

[steve]

I expect that ISC will work as long as it's not shorted or open.

You always need to check the resistances of the coils before installing a ISC and when taking one out due to problems. That way you know if the replacement is "good" and if the old one already did damage.

 

[timm98gst]

well it turns out that my stock isc was ok after all - guess i'll have to keep looking for the cause of my idle surge and p0505 code - thanks for the input though guys

 

[nice97civic]

FIAV? sometimes that is the culprit of idle surge. im not sure what youre code translates to but see if the FIAV is causing your problems

 

[timm98gst]

the p0505 code reads 'idle control system malfunction' - if it wasn't the isc i was also thinking the fiav
here are my symptoms: only have about 480 miles on the car since full engine rebuild by the way:
when starting the car up cold in the morning it idles at about 1500 - i drive about 1/2 mile to the first light and stop - car still idles about 1500 - i get on the highway and drive about 7 miles, exit and stop - idle then surges up and down between about 1000 and 1750 - annoying - same thing happens on the way home - high idle until nice and warm, then surge - never dips below about 700 or stalls
no loose vacuum lines, no dirty tb - i still have a few other things to rule out such as throttle cable, leaks, etc. - shouldn't be biss - everything was fine up until about 50 miles ago when the check engine light popped on and the surging started

 

[voodoogsx]

the p0505 code reads 'idle control system malfunction' - if it wasn't the isc i was also thinking the fiav
here are my symptoms: only have about 480 miles on the car since full engine rebuild by the way:
when starting the car up cold in the morning it idles at about 1500 - i drive about 1/2 mile to the first light and stop - car still idles about 1500 - i get on the highway and drive about 7 miles, exit and stop - idle then surges up and down between about 1000 and 1750 - annoying - same thing happens on the way home - high idle until nice and warm, then surge - never dips below about 700 or stalls
no loose vacuum lines, no dirty tb - i still have a few other things to rule out such as throttle cable, leaks, etc. - shouldn't be biss - everything was fine up until about 50 miles ago when the check engine light popped on and the surging started

Interesting, I've had a similar issue on my car with the same code.
I pulled some of the vac lines when initially trying to figure out an idle issue. Those lines ended up not holding too well after being pulled off due to heat cycling and being old. I managed to fix the high idle issue as far as I can tell after replacing the vac lines from the egr and other components above the intake mani. The fitting were so loose that they would either pop off or just let enough air escape. I know you mentioned you didn't have a leak, but I'd double check and make sure all of those lines are on tight.