90 ICS VS. ALL Others

4Motion4g63 · 03-19-2008, 12:16 AM

Just Sick Of Failing ISC and Found Out that 1990 cars had the ONLY truly different ISC,
Now they will still work on all later model Throttle bodies as I have been told.....

I was sorting thru a BIG box of throttle bodies and checking ISC( 10 or so )for a good one and there were about 5 BAD 91 UP and EVERY 90 Only one checked out good? I myself have gone thru at least 4 already since I bought my DSM and its getting old, I am not even confident that a BRAND new one would be a sure thing for long...

Just want to hear some Feedback about ISC from the 90 cars! do you have one, How frequently Is it a problem, Or Do you have the 91-Up ISC and HOW often do you have a problem?

Is there anything that could be done to PROLONG the life of a ISC and is there anything that causes FAILURE?

Any Feedback on this Festering boil of a problem in our Cars Is greatly Needed, Cause its Not bad enough to Kill one, It just gets on your damn nerves

90 ISC

91-Up ISC

turboglenn · 03-19-2008, 10:20 AM

Are you just breaking that little nipple cap off teh end where it plugs airflow? I had huge issues with that at first, but i was programming the cycles for the ISC from scratch on a stand alone. I don't know what causes them to fail so bad of stock ECU vehicles though

yokotabrat · 03-19-2008, 11:55 AM

Does your car still have the FIAV? If so, there's a chance that's leaking coolant into the throttle body and isc and killing the isc.

Also, have you checked the ecu for damage to verify that you haven't destroyed the isc drivers? If the coils on the isc go low resistance, they overload those driver chips in a hurry and you'll no longer have a correctly functioning isc even if you put a good one in.

4Motion4g63 · 03-19-2008, 03:37 PM

I have looked at my ECU several Times and It always was probably the Nicest Part Off my car...But im sure You couldnt see failed programing......

What IS FIAV?

turboAWDfanatic · 03-19-2008, 04:21 PM

Pulled the ISC off my '90 TB when I rebuilt the shaft seals a few months ago and it checked out fine. *shrug*

yokotabrat · 03-19-2008, 05:02 PM

Quote:

Originally Posted by 4Motion4g63

I have looked at my ECU several Times and It always was probably the Nicest Part Off my car...But im sure You couldnt see failed programing......

What IS FIAV?

FIAV = Fast Idle Air Valve. It's the lower portion of your throttle body that has the two coolant lines running to it. How are you determining the iscs are going bad? Are you measuring the resistance of the coils?

pneumo · 03-19-2008, 09:29 PM

Since you have extras, you can use the parts to make one good ISC. Check it out.
The ISC Assembly Thread - Rebuild your own ISC!!! - DSMtalk Forums

cbassgsx · 03-19-2008, 10:31 PM

I have an ecu that look similar to this from a 1990 isc
Need Major Wiring Help!!!

4Motion4g63 · 03-19-2008, 10:34 PM

Quote:

Originally Posted by yokotabrat

FIAV = Fast Idle Air Valve. It's the lower portion of your throttle body that has the two coolant lines running to it. How are you determining the iscs are going bad? Are you measuring the resistance of the coils?

Yes Meter out at 40ohms across the board, Start With pin #1 to pin#2, Pin #2 to Pin #3 Ect....
I did the test correctly.

The 90 I had Installed DID not work but it may be that i picked up a bad one too.... Possible cause I was sorting so many. And I just threw a Known Tested good 91-94 style one in and all is FINE now. Just still WANT to find a Better solution to this problem and will entertain rebuilding them, I work in Car Audio shop so Doing any kinda Electrical repair is up my alley,
I had NO problems installing my own Eprom chips and replacing caps in bad ECU so that should be cake if its possible...

4Motion4g63 · 03-19-2008, 10:44 PM

DSMISC FAQS page
Well This just stated that Higher Ohm load the Better and the one I had was a NEWER style ISC /black with the 2 screws on the bottom case.... But still I had Ramping, Must have been the other part failure....

this is good though IM learning what to look for in a decent ISC and its not so random anymore.

cbassgsx · 03-20-2008, 10:44 AM

well if you want to make them higher resistance just put a sandblock resistor in series. I would think a 10 ohm resistor would stop coils from frying if thats what keeps happening.

RipperXX · 03-20-2008, 12:13 PM

I have a 90, and mine is fine far as no auto rev and or stalling.