ISC Issues...

[Liger Zero]

Hey guys, I just replaced my stock ISC that was malfunctioning with a black upgraded ISC hoping to solve my terrible idle/stalling issues. After I replaced it I disconnected my battery as to reset my ECU so that it relearns everything with the new ISC installed. Well, when I first start it up it jumps to 2k then slowly works it way down to 1200rpm and sits there on idle. Once driving it, as I downshift and let the clutch out to come to a stop the idle surges back n forth between 1200-2000rpm. After driving it awhile, shutting it off, and then starting it again while warm it idles around 900 and dips to 500rpm, and if I rev it to 2000rpm it drop and stall. This is the same problem I had before but it doesnt stall as much as it did. Do you think something is still wrong with this ISC or maybe the ECU hasnt relearned everything yet? I have driven it about 30 miles since the replacement. Im running out of ideas and its driving me nuts!

 

[HIGHPSI4]

Have you checked for vacuum leaks?

 

[Liger Zero]

yes i have. i actually replaced all of my vacuum lines recently. I just bought the car and most of the lines were gone. So I found I diagram and tried to follow it the best I could in hooking everything up. I cant guarantee its 100% correct but I believe it is.

 

[SnowBird]

did you set your idle correctly first?

 

[illeffekt vr-4]

Set your BISS as per vfq.com and report back.

 

[steve]

Did you check the coils on the bad one to see if it would have blown the drivers in the ECU?
If any were shorted you need the ECU fixed before the new ISC will work correctly.

 

[Liger Zero]

THANKS GUYS!!! I believe I got my issue solved! The BISS was practically unscrewed the whole way, and when I started tightening it after grounding those 2 connectors as stated in the vfaq, she idles smoother than ever!!! Only had one little problem is when I shut it off mid test drive to restart it, I revved it right away and when the rpm's came back down it stalled, so I restarted it and did the same thing, this time it dipped to 500 rpm's but did not stall. So I guess I should back the screw out a little more. Now the only other thing I noticed is that it has terrible throttle response, is there a way I can adjust that? THANKS AGAIN SO MUCH GUYS!!!

 

[Jeff99GS]

As steve said test the OLD ISC coils.

If the short out they will cause the drivers in the ECU to fail.

I would also replace that O-ring on the Biss Screw.

 

[Liger Zero]

Well turns out that it isnt fixed. It lasted for a little while but then started stalling just by sitting there on idle, I dont get it... I tore apart my old ISC but nothing looks to be messed up. Only thing is I do not know how to test my ISC coils to see if they are bad or not... What do I need to do? Oh, and the only other thing is that the previous owner stated that he already replaced the ISC once with a junkyard one which is the one I just took out. So I dont know if the original one was messed up or not. But any help would definately be appreciated! Thanks!

 

[Jeff99GS]

Looks like you may be needing a new ECU at this point. Or at least send yours out for repair.

 

[Liger Zero]

you really think I need a new ECU?

 

[steve]

Unlikely but you will need it looked at/tested to make sure that the ISC traces and drivers are functioning.

 

[Liger Zero]

so do i take it to a dealer? or how can I have it tested? Is it something that I can do myself with the right tools?

 

[nongthep]

DmTaLoN's Idle Speed Control Test/Fix Page!

try this

 

[Liger Zero]

DmTaLoN's Idle Speed Control Test/Fix Page!

try this

THANK YOU SO MUCH!!! Thats EXACTLY what I needed!!!