isc not working

[newtodsm97gst]

idle surge plus leaning. i test ohms 29.0 on all of them but when i unbolt it from tb to check if its moving. found out that when i turn the key on on position, it doe not move. does it means its shot?

 

[dsmer1]

well, it makes sence that your leaning out with an idle surge. if it is a 2g isc (if you pick one up from an auto parts store be shure to call it a iac or they wont know what your talking about; learned that first hand) it should be 40ohms + or - 1 ohm across all coils. but from what you state, it sounds like it is shot. the isc is one of the culprits to idle surgeas well,

 

[snowborder714]

Not all "2g" ISC's are black (ones that should read 40&#937. If it's tan, it'll read around 30Ω like the OP is seeing.

 

[dsmer1]

yes correct. the tan IACs are supposed to read 30ohm + or - 1 ohm. but from my knowledge the TAN one

http://i68.photobucket.com/albums/i17/paulvolk/IAC external install/20120930_181728.jpg

was installed on the "1g" dsm.

wheres as the black one

http://www.dsmisc.com/dsmweb-dw/_images/littlepics/P1010001- crop.jpg

was installed on the "2g" dsm.

but the tan ones are more suseptable to blow out coils, therefore, a "2g" one is installed instead.

please correct me if i wrong

 

[snowborder714]

From my knowledge, the black ones were a late 2g thing, while some early 2g's still came with the tan one. Yes, the tan ones are more susceptible to having problem coils.

Not that this should matter, as long as the OP knows the correct values to look for in relation to their specific ISC.

 

[dsmer1]

oh okay. i wonder if it had anything to do with the new ecu that was introduced mid 95. but yeah if he has the tan one hes in spec. but if he says he pulled the IAC out with it still plugged in, and turned on the ignition, and it did not move, seems to me its blown. what do you think?

 

[snowborder714]

All he has to do is pull the ECU and check the ISC drivers.
driver01 [ECMTuning - wiki]

If they look ok, then I'd try another ISC.

 

[newtodsm97gst]

i have the tan one. i checked the ecu and there"s nothing wrong with it, did not see anything blown or burnt. is there any way or how to check the wires that connects to isc/iac? that might be my problem. because when I turn the car on and off, I dont see the tip of the isc/iac moving?

 

[mizak82]

I have an extra tan one. Bought a new black one. . Wasnt the issue. Hit me up if interested. They are expensive new.

 

[snowborder714]

i have the tan one. i checked the ecu and there"s nothing wrong with it, did not see anything blown or burnt. is there any way or how to check the wires that connects to isc/iac? that might be my problem. because when I turn the car on and off, I dont see the tip of the isc/iac moving?

Using a multimeter, you can check the resistance of all the wires.

When you turn the key to ON and have the ISC plugged in, do you hear it clicking or making any noise?

 

[newtodsm97gst]

Using a multimeter, you can check the resistance of all the wires.

When you turn the key to ON and have the ISC plugged in, do you hear it clicking or making any noise?

nothing at all. no clicking or any noise, that's what I assumed that it might be the wires.
I'm still going to get or test a good working ISC/IAC just to be sure.
how do I exactly check it with multimeter, can you guide me step by step? I'm not very knowledgeable about electronics stuff. thanks.

 

[snowborder714]

Example multimeter. You want to use one of the lower settings in the Ω category, or even the mode that beeps upon continuity (to the right of the Ohm section with little red sound logo)

You must be logged in to view this image or video.

The ISC plug contains 6 pins. This post shows the colors.
http://www.dsmtuners.com/forums/151542243-post30.html

4 of those wires go back to the ECU. This post will help you locate what pins they go back to (pins 4, 5, 17, & 18). [Note - this link says Gray for wire colors, the above says White. They are the same.]
http://www.dsmtuners.com/forums/articles-tuning-ecu/281763-2g-turbo-ecu-pinout-w-wire-colors.html

The other two wires are both red. One goes to the CPS (crankshaft position sensor) and the other to the MFI relay.

Take one probe from the multimeter and put it on a single pin inside the ISC harness plug. Then take the other probe (you might need some sort of extension to reach the ECU pins) and put it on the other end of the wire. If you have it set on one of the Ohm values, you're looking for a resistance reading around 002 or so (with the meter set to the 2000Ω mark. If you have it set on the beep mode, you should hear a constant tone when both ends are touching the multimeter leads.

If your resistance is higher than 002 or so on a wire (give or take a small amount), then you might have a problem with that wire.

 

[Blurred Talon]

If you need a new ISC, check out dsmisc.com. They sell brand new OEM ones for cheap.

 

[newtodsm97gst]

If you need a new ISC, check out dsmisc.com. They sell brand new OEM ones for cheap.

$167 is not cheap IMO, I'd might aswell by from autozone with lifetime warranty for $86.

 

[Blurred Talon]

I rather OEM parts then crappy parts store stuff.
It's worth it imo.

 

[TexasTurbo]

I wouldn't even mess with all this ohm meter balogna. You need a lantern battery to properly test the coils and it's a pita to do anyway. Just leave the key in the on position, plug the isc into the harness and hold it in your hand as you connect the negative cable. If the isc ranges through it's motion smoothly then it's fine..... or you can do all this other stuff and waste a bunch of time you could be boosting with.

 

[newtodsm97gst]

I wouldn't even mess with all this ohm meter balogna. You need a lantern battery to properly test the coils and it's a pita to do anyway. Just leave the key in the on position, plug the isc into the harness and hold it in your hand as you connect the negative cable. If the isc ranges through it's motion smoothly then it's fine..... or you can do all this other stuff and waste a bunch of time you could be boosting with.

yes I know, but the problem is when i turn on and off the car while checking the ISC, it's not moving at all. the resistance on ISC and ECU is good, thats why I wanted to check those wires if their getting power or connecting to ecu, because its not moving at all while I conduct the testing. thanks

 

[IceMan526]

I just learned something new about these ISC's. Mine was surging so I took mine out and ohmed it out and all the pins were good so I put it back in. I chased the problem for a little while until I went back to the ISC. I pulled it out and bench tested it by putting power to it with a power probe. Nothing, didnt move or make noise. I took the little front cover off held on by 3 screws and come to find out it was so corroded inside that it was seized up. It was getting power but would not turn. So I suggest taking it apart just to make sure its good inside.

 

[newtodsm97gst]

I just learned something new about these ISC's. Mine was surging so I took mine out and ohmed it out and all the pins were good so I put it back in. I chased the problem for a little while until I went back to the ISC. I pulled it out and bench tested it by putting power to it with a power probe. Nothing, didnt move or make noise. I took the little front cover off held on by 3 screws and come to find out it was so corroded inside that it was seized up. It was getting power but would not turn. So I suggest taking it apart just to make sure its good inside.

i'll check it out right now thanks
I just checked it and wow your right it corroded and kinda look like rust... that explained it I guess..