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ISC Module Replacement Question


eldoetc95

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Hello all,

I have a question on replacing my ISC module. I have a '95 Eldo ETC, and this Saturday, my idle shot up to 3000. The previous week, it would start fine, but occasionally, it would idle at 2000 RPM. I would tap the accellerator, and idle would come back to normal, but I could see the storm coming. As many previous posts had stated, the first thing I did was check the TB. It was ugly :( . Pulled it off, cleaned it very well, including the EGR tube, which had a tiny opening in it from all the crud, reassembled it and....idle at 4000 RPM! Not good :( . Today, I got home from work and pulled the ISC module off and lo and behold, the car wouldnt idle, but would stay on and run smooth as long as your foot was on the pedal-this was good. As the car was running, the ISC was ratcheting like mad, but was not moving, seems like it was skiping a tooth, as I have read that this can happen. I tried putting pressure on it past the 'detent' like previous posts stated, but I couldn't budge it. The reason I want to replace it is, when removing the ISC Module, the 3 nuts that held it on the bracket were not the same! 2 of them were normal nuts, and 1 was a nylok nut. Since I did not purchase this car new, I suspect that this unit as been serviced in some way before and I don't know if someone has messed with the set screw that is tapped in the plunger. So to eliminate any variables from the past, I want to replace it. Which all this disertation leads to my question. Are new ISC Modules somewhat set to spec as far as the bolt that is screwed into the plunger? Or do I have to adjust that lengh as well as doing the ISC setup via the OBD ( I have the manual, so I have that down........I think). Bad part is, my little parts book doesnt have the part number for the ISC so I have to go to the dealer parts counter instead of going online to GMpartsdirect.com. If anyone has changed their ISC Module and has any helpful hints, I would really appreciate it. Many thanks in advance and thanks to ALL the members on this board for their help and comments.

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Very simple to swap out of course.. I believe the part number is 17113388 (don't quote me on that though because that's for my 99)

Your '99 has an Idle Air Control solenoid, not an idle speed control motor.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I replaced my ISC motor in my 93 STS 4.6l and as a result I noticed that plunger was not preset to any set spec. Once the unit was mounted in place I stepped through the Idle Learn procedure as well as the Throttle Position learn both of which were found in the factory manuals. Good luck.

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Very simple to swap out of course.. I believe the part number is 17113388 (don't quote me on that though because that's for my 99)

Your '99 has an Idle Air Control solenoid, not an idle speed control motor.

Hmm.. I took it apart once to clean it and it sure looked like a motor.. It is like a little plunger with a screw in the middle and the screw spun around and moved the plunger .. I know that cuz i took it out without unplugging the connector and it started to go crazy in my hand heheh..

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I too took apart my ISC motor thinking that I could fix it as it was ratcheting quite slow and got a good look at the inner parts. I didn't have as much fun as you bigfoo as I disconnected before starting...sounded like fun though! :lol:

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Very simple to swap out of course.. I believe the part number is 17113388 (don't quote me on that though because that's for my 99)

Your '99 has an Idle Air Control solenoid, not an idle speed control motor.

Hmm.. I took it apart once to clean it and it sure looked like a motor.. It is like a little plunger with a screw in the middle and the screw spun around and moved the plunger .. I know that cuz i took it out without unplugging the connector and it started to go crazy in my hand heheh..

It is a plunger that controls the amount of air entering the throttle body via a bypass air channel vs. the old style ISC motors that opened/closed the throttle plate.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Very simple to swap out of course.. I believe the part number is 17113388 (don't quote me on that though because that's for my 99)

The 93 STS 4.6l part number for the ISC motor is 17112866....

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I just bought one from gmotors.com (Brasington parts) for $81.00. Email them the year, make and model car you have and part needed and they'll reply with the price and the part that fits your car. Simple as that...no part number needed.

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I believe they'll need the VIN also for a more accurate part match. Rockauto.com has an aftermarket ISC for $10.00 less, but I went with the AC Delco OEM part from gmotors.com

Hey what was the result of replacing your ISC I never heard the outcome?

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Adalack needed it, so I ordered a new one the other day, haven't received it yet. The numbers didn't match on the one Adalack sent, so I presumed it may have been the wrong one...not calibrated for my car...who knows. As soon as I get it I will take off the one Adalack sent and ship it back to him and install/calibrate the new one. I'll be sure to keep you posted. Thanks!

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:D Hi Everyone,

Just wanted to update my ISC change. Got the part from GM, the Idle plunger was allready fully retracted, so I didn't have to 'fool' it with the throttle like bbobinski said I might have to have done. Installed it, disconnected the battery for 60 seconds and WALA! :lol: Idle smooth at 1200. Figured it was hi because I had given the TB a thorough bath, so with the factory manual in my lap, I performed the Idle Speed ReLearn process and the thing just purrrrrrrrrrrs between 800 and 900 RPM. I have my CADDY BACK!! :rolleyes: Thanks to EVERYONE that answered and to Guru for this board. Great Board, Great People!! Now I can get my Vet ready for winter storage :D . I have 2, 10 year old cars, but wouldn't trade them for the world. Now to get the '69 Chevelle back together! B)

Thanks Everyone!

eldoetc95

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