Resolved ISC motor harness side 6 volts?

[yoyo13131]

I know the manual says only to use a 6 volt battery to test the ISC motor. But does that mean the harness side of the Eclipse should be applying 6 volts to the ISC motor as well? With key on my harness is applying 12 Volts on two red wires going to ISC Motor

 

[luv2rallye]

Harness correctly applies 12v but pulses the ground on the other side of the coils. For testing you use 6v however so you won't burn out the coils.

 

[yoyo13131]

When you pull out a working ISC motor and leave it connected and turn the key into the on position, is the motor suppose to cycle in and out? All mine does is twitch with no real movement.

 

[juntjoo]

so what kind of symptoms did you have? mine does the same and I have a horrible idle.

 

[yoyo13131]

Well I'm having cold start issues becuase of my FIAV which I've adjusted before. But the idles always been either to low or to high depending on temperature outside and it seems like the ISC isn't controlling the idle like it should. When AC is turned on idle dips real low 600-700 rpm and sometimes isn't enough to keep the AC compressor running so it cycles on and off constantly. Brand new OE ISC motor didn't change anything.

How do I make this LED matrix the trouble shooting guide talks about? It's really vague on how to make it or where the resistors are soderd.

Oh and when you test a ISC motor with a 6v battery should you beable to see the motor move, or just twitch?

Oh and ever since I bought the ISC motor I tested resistance and it was 10 ohms higher then max sock levels. Idk if that's just how newer ones are.

And yes I've tried grounding both the ecu and ISC motor and tryed setting idle to 750 but biss screw bottomed out at 850ish-rpm (all new o-rings and intake gaskets)

 

[juntjoo]

Well I'm having cold start issues becuase of my FIAV which I've adjusted before. But the idles always been either to low or to high depending on temperature outside and it seems like the ISC isn't controlling the idle like it should. When AC is turned on idle dips real low 600-700 rpm and sometimes isn't enough to keep the AC compressor running so it cycles on and off constantly. Brand new OE ISC motor didn't change anything.

How do I make this LED matrix the trouble shooting guide talks about? It's really vague on how to make it or where the resistors are soderd.

Oh and when you test a ISC motor with a 6v battery should you beable to see the motor move, or just twitch?

Oh and ever since I bought the ISC motor I tested resistance and it was 10 ohms higher then max sock levels. Idk if that's just how newer ones are.

And yes I've tried grounding both the ecu and ISC motor and tryed setting idle to 750 but biss screw bottomed out at 850ish-rpm (all new o-rings and intake gaskets)

so your old ISC didn't cycle back and forth as you mentioned or was it the new one? I'll assume old. I also have the cold start issue and the symptom with the AC on causing the idling to struggle more AND either high or low idle. lately been low I believe since I brought it down by adjusting the accelerator cable. and I'm also in the process of getting a replacement ISC -I just had to return this used one because it tested bad right out of the box. so it looks to me like we might have the same problem which wouldn't be too encouraging for me since your new ISC apparently hasn't helped solve the problem. well please keep this thread updated. I'll contribute what I can myself.

I've read that the newer black ISC is supposed to have 10 more ohms. so is it your new ISC that isn't cycling in and out like I've seen in several videos and read about? I'm wondering if maybe my ISC isn't bad and that the ECU isn't providing it the right signals to make it cycle in and out correctly because I tested the voltage on the harness and terminals 2&4 get 12v but the Haynes manual says only one terminal is supposed to show voltage. I don't know if the LED method is a better test or not so I may be looking into that test too. so I'm wondering if this could be an ECU problem. have you looked into that? anyway, good luck. let's see if we can figure this out

 

[AlaskanDsm]

I had the exactly the same problem. The ISC drivers on my ECU were shot. When I sent my ECU in for the non-eprom conversion and ECMLink, they replaced that driver. Now my idle is working just fine.

Example:
driver01 [ECMTuning - wiki]

This is what a properly operating ISC should look like when initial power is applied.
http://www.dsmtuners.com/forums/152483246-post5.html

 

[yoyo13131]

Omg I've been trying to find a video like this forever!

My old and new ISC motor both twitch and dont do anything if I copy the video. I'm going to pick up another ecu tomorrow to see if there is any difference.

I have two middle pins that my harness is giving 12 volts also, don't know if that's normal.

Can the drivers be bad even if there isn't any burn/black marks?

 

[juntjoo]

Yeah, my #2&5 pins also have 12v and haynes manual says only one is supposed to. So perhaps that's a symptom of a bad ecu.

 

[yoyo13131]

Ok progress!

I changed my original ecu to a 1990 2.0 non turbo manual ecu and the ISC motor actually moves now! Not as much as in the video but it's certainly moving now!.... I haven't tested it while driving yet becuase I think my balance shaft belt broke or I broke my pressure plate, its vibrating a lot more the usual and sounds really bad while driving. When I start it up it sounds like a little belt squeak then goes away. It started happening right after I shifted redline from 1st to 2nd perfectly but my tranny grinded really bad and whole car started to shake while in gear and on neutral if I rev it.

Also both original ecu and 1990 ecu both have 12 volts in pins 2 and 5

Anyone know of a way to look at the balance shaft belt without removing all accessory belts and crank pulley?

 

[juntjoo]

interesting, can't Wait to see how it drives. I will definitely start checking out my ECU.

about the balance belt, I'm just a noob, but I did a BSE and from what I saw there isn't a way to get in there without removing the TB cover, which the drive belts are on top of. good luck and keep this thread posted on your progress

 

[yoyo13131]

I hope I broke my pressure plate and not my balance shaft belt. I really don't want to retime this engine in the car. That's going to be almost impossible IN the car this time. It'll be months before I drive it again.

 

[juntjoo]

ah man, you were my ticket to solving our problem. well I bet you did with the new ECU. anyway, you oughta do the BSE as I did. I believe I felt some HP gains from it, plus you won't ever have to worry about it failing on you ever again and they say the balance belt failing often results in messing up your timing belt so...

 

[yoyo13131]

Yeah if the balance shaft did brake I'm going to eliminate them all together becuase I'm lucky it didn't take out the timing belt. Hoping it's clutch related. I'm gonna start taking the car apart so I can get it running again to see of the new ecu worked.

 

[AlaskanDsm]

Honestly, retiming the engine with it still in the car is not too bad. I had my water pump go out on me a couple months back and I had to do the water pump and re-time with the engine in the car. It isn;t too bad. I don't have any information about doing the BSE in car though.

 

[yoyo13131]

Honestly, retiming the engine with it still in the car is not too bad. I had my water pump go out on me a couple months back and I had to do the water pump and re-time with the engine in the car. It isn;t too bad. I don't have any information about doing the BSE in car though.

Yeah i checked the balance shaft belt and its still intact, i guess maybe it jumped a tooth or something. I see a pile of metal shavings right by the balance shaft idler pulley though, (everything has 20k miles on it) I'm gonna pull the engine this weekend and check everything since I'm not even going to attempt to time the engine in car. way to stressful guessing weather it looks timed or not viewing the cam gears not straight on. Better on a engine stand. Plus the engine is pointing in the wrong direction! Timing belt should be pointing at the radiator! ugh

 

[AlaskanDsm]

Good luck with that man. I really hope it isn't too serious. But seeing metal shavings usually isn't a good sign either. Let us know what happens!!!

 

[yoyo13131]

Good luck with that man. I really hope it isn't too serious. But seeing metal shavings usually isn't a good sign either. Let us know what happens!!!

Well I found out what broke....
Clutch looked fine, pressure plate looked fine, flywheel looked fine.... then I noticed two flywheel bolts just hanging there... I broke two flywheel bolts off into my crankshaft. Anyone know of a good way to get them out? These where brand new bolts from the factory too red loctited to spec with only 20K on them

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