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ISC Failed

Dan D

Well-known member
My idle started dropping under load and wouldn't maintain the 900rpm set in the eprom. Logger shows 120 trying to bring it up. I fiddled with the BISS to get the rpms up over 900 and the ISC counts went down to zero with no effect on the actual idle speed. The ISC is about two years old, purchased from DSMISC.

Next, I ohmed out the coils they check out at 40 ohms which is right on the money for the newer version ISC.
I pulled the ISC and hooked up a power supply. It draws current, but nothing moves.
I pulled it apart and the pintle freely spins. I tried winding it up and then putting it back together and applying power to the other coil to see if it would turn the other way - no dice.

Anyone had similar short lifespan on these newer version ISCs? If the coils are good and it draws the appropriate amount of current when excited, why wouldn't it turn? Does the rotor become demagnetized?

I have a very strong magnetizer here at work. Maybe I'll put the rotor on it and see if it comes back to life. I just have to figure out which pole is which.
 

Brunoboy

Well-known member
did you ground out before adjusting the biss?
 

Dan D

Well-known member
No. I wasn't setting my base idle speed just jacking up the idle so the ISC control loop would overshoot and begin to compensate the other direction.
 

dmj

Well-known member
I have the same with problem with the newer style ISC lasted less than 18 months coils checked ok but wont compensate for ac load. going back to old style rebuilt.
 

Brunoboy

Well-known member
What you want is a ISC/FIAV complete blockoff. idle will be low on cold start, but its liveable, I have one installed now after my isc fried my ecu, the one above is shown as "FIAV Blockoff" you want an ISC/FIAV Blockoff.
-Shane
 
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turboaddict

Well-known member
the one above is both the fiav has a hole in it that is squared off, the hole in this is for the center bolt:)
 

Dan D

Well-known member
My FIAV has been blocked for years. I want my ISC because it makes the car much nicer to drive in traffic and it saves on the footwork needed to keep it from stalling. I had no ISC for a long time and it sucked having to balance between lights being on, fans being on, etc vs having a livable idle speed plus during the winter its 30-40 degrees in the morning and 60-80 in the afternoon. The idle just doesn't handle 40 degree temperature swings without the ISC very well.

I ordered a new one, I just hope it doesn't crap out as fast as the previous one did.
 

Dan D

Well-known member
I ordered a new ISC. Everything works well now. I got one from Amazon.com from $80. It ended up being the same OE part as the one from DSMISC.com. Tripple Diamond marking and everything. Hopefully this one lasts a little longer
 
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