bad isc, running lean???

[boost69]

hey ive been having an on going problem with my car and im trying to narrow down the possibilities, i am running very lean, high 18s and low 19s at idle and my car just seems to run funny, while it was running i unpluged the isc and nothing changed, would that be my problem?? also my car is reading about14-15 psi of vac at idle would the isc cause that to be lower then normal as well, and would the isc cause me to run super lean like that??? please help

 

[gofer]

Dejavu? I guess one thread wasn't enough? Running Lean Rough Idle Low Vac HELP!
You said the car has a CEL from you wideband, why? and how do you know its just from your WB, have you checked it lately? You still never posted the results up from your BLT and thats typically what it is if you've got low vacuum & lean AFR's during idle. If you want to test your ISC there are two different ways to do it, using a multimeter or by visually checking it while its plugged in, here's videos for both.

YouTube - DSM ISC motor testing & Replacement

To test it this way you'll want someone to turn the key to the "ON" position while your standing outside the car hold the ISC with it still plugged in, just removed from the TB. It should move in and out SMOOTH like the video, if it just sits there and shakes its bad.
YouTube - DSM ISC

 

[boost69]

i ran the cel codes and its the 02 sensor where my wide band is hooked up

 

[gofer]

Where is it hooked up, front or rear o2 sensor?

 

[boost69]

sensor 2, and i was reading that bad isc would make it run rich my fuel pressure is 41 so i know thats good,

 

[gofer]

sensor 2, and i was reading that bad isc would make it run rich my fuel pressure is 41 so i know thats good,

A bad ISC has nothing to do with AFR's it just makes the car idle irratic so I don't know where you read that it would make it idle rich. Besides, you said your cars idle is LEAN so even if it did make your car idle RICH thats not what your cars doing.

Your car is showing symptoms of air going into the motor and not being accounted for by the MAF which would cause a lean condition, exactly what a vacuum leak is and exactly what your cars doing. Someone mentioned it in your other thread you posted about taking a can of carb cleaner and spraying it around your IM and TB which is a cheap and easy way to find vacuum leaks. If the engine revs up when you spray it theres a leak.

 

[boost69]

i did that and i have no leaks

 

[kmj 4g63t]

I used the same method as the first video to check my isc, since I got a cel and irratic idle all the time! All coils were 32-33 ohms but pin 5,6 read 192.5 ohms, since I never saw a isc that was bad have high resistance (only saw OL on multimeter) is it bad. To me I think it is since the resistance is sooo high the connection would be terrible and the isc would throw the code because of the poor connection of the coil.

Also when I took out both bolts from the isc and tried to remove it, it`s completly stuck as if someone used super glue to stick it in!! I don`t want to heat it up just in case the throttle body gets damaged, I used a flat head screw driver and hammer to try and get it loose but no luckk WTF!

 

[steve]

All coils were 32-33 ohms but pin 5,6 read 192.5 ohms, since I never saw a isc that was bad have high resistance (only saw OL on multimeter) is it bad?

Yes, it's bad. The coils that have high resistance are bad but at least they don't damage your ECU like those that measure 10 ohms or lower.

 

[kmj 4g63t]

Yes, it's bad. The coils that have high resistance are bad but at least they don't damage your ECU like those that measure 10 ohms or lower.

Thanks for clarifying!! Wasn't sure I was freaking out hoping the ecu was fried but 5 volts was there !

To OP did you end up finding the problem?

 

[steve]

Wasn't sure I was freaking out hoping the ecu was fried but 5 volts was there !

5v was where? The ISC power pins (two center ones) get 12v. The ECU grounds the other pins in sequence to step the ISC.

 

[kmj 4g63t]

5v was where? The ISC power pins (two center ones) get 12v. The ECU grounds the other pins in sequence to step the ISC.

5v at ecu sorry didn't clarify haha. I know the ecu is basically just a ground that turns sensors on and off.

 

[steve]

5v at ecu sorry didn't clarify haha.

You still haven't clarified, there are 52 pins on the 1G ECU.
Even if you were talking about 1 of the 4 for the ISC a 5v reading would be wrong. They should either be very close to 0v or battery voltage depending on if they were active or not.

 

[321]

If you are running the wideband in place of your 2nd o2 sensor with out a simulator that could cause abnormal o2 readings. Try putting the stock o2 sensor back in, and see if their are any changes.

 

[kmj 4g63t]

You still haven't clarified, there are 52 pins on the 1G ECU.
Even if you were talking about 1 of the 4 for the ISC a 5v reading would be wrong. They should either be very close to 0v or battery voltage depending on if they were active or not.

No was just talking about power for the ecu. But I just installed my New isc and cel came on as well as idle surge.......