Why can't I just disconnect the ISC as a test to see if it stops idle surge?

[4gfun]

I know that I can take the ISC off the TB to check it's coils, but why not just disconnect it temporarily to see if the idle surge goes away?

Being technical about things is just fine, and believe me I know how to use a VOM....but in my setup, the ISC is a little bit difficult to reach.

Thanks

 

[GMANS89GT]

I know that I can take the ISC off the TB to check it's coils, but why not just disconnect it temporarily to see if the idle surge goes away?

Being technical about things is just fine, and believe me I know how to use a VOM....but in my setup, the ISC is a little bit difficult to reach.

Thanks

YOU COULD DO THAT BUT THE ECM WILL GO TO LIMP MODE !

 

[4gfun]

YOU COULD DO THAT BUT THE ECM WILL GO TO LIMP MODE !

Thanks, well I pulled the ISC with the vehicle running and it still kept surging.

Is it safe to say I can look for other causes, or do I really need to get it off the car to test it?

It is a little bit difficult to reach on this car, because someone modified the fuel rail before I got it.

BTW when I took a look at the ISC, it looked different than anyone I have ever seen.

The last two pins were smaller and much closer together. Every other pic that I have seen for the ISC has all of the pins being the same size. WTF

This engine has the JDM red valve cover. Wondering if this is a JDM engine and if the ISC's on those are different.

 

[GMANS89GT]

i believe the sensors are diff on the jdm . the red cover was on the cyclone . check the block #s .

 

[blcknspo0ln]

You can't simply pull the plug for the ISC (nor can you physically remove it from the TB) to diagnose it. When you remove the plug, the plunger in the ISC will stop moving from whatever position it is in. Either open, close, or somewhere in between. Doing this does nothing to help your situation. I've found the easiest way to check an ISC is to take the two 8mm bolts out and remove the ISC. Keep the ISC plugged into the harness and have a friend turn the ignition to ON. If the plunger on the ISC moves in and out (like it's adjusting itself) then it's working ok. If it's shot, it'll either not react at all or just vibrate without the plunger moving.

Check that, make sure the Oring on the ISC is good, and seal it up when reinstalling. The ISC should be either tan or black with 6 symmetrical electrical male ends.

DmTaLoN's Idle Speed Control Test/Fix Page!