This is another rev/idle nightmare. I will include a short clip of what the car does. I can get it to idle great. The car was a y7 now a y8. I have wired the vtec, knock and the two wire conversion for iac. I have an ecu from auto y8 (p2p).

Idles great just when I try reving it slowly up it bouces up and down from 1500 to 2000 rpm.

I have cleaned the IAC, replaced the coolant temp sensor, bleed coolant, swapped dizzys more than one, lol. I also swapped ecus back to the y7 auto. In addition I also pulled intake to plug hole in TB while pushing throttle up, none of which changed the condition?? I also adjusted idle screw and again no change from 1500 to 2000??

The check engine was on right from get go and I had them read. They said it was idle control circuit? I also swapped the TPS and map sensor, again no change occured.

I did put a y8 5sp ecu in and I could make it run just fine between 1500 and 2000. I could push it anywhere in between and it ran just fine?? however no automatic controls.

Do anyone have any clues? Im at my wicks end...I so appreciate any and all help u guys can lend me.

watch tach in this video http://www.youtube.com/watch?v=0D_YfJbber0sorry sound sucks.
I'm actually letting it idle for a second then I push accelerator up to 1500 trying to slowly push up past 2k. I then show you how I can cruise right by it if I want to really push on it.

 

If you solve your check engine light then your idle problem will probably be solved.

 

That would be helpful if I knew what it fact it was. This is why I detailed what all I had done so far.

I'm mainly looking for someone with same or similiar problem to detail what there fix was.

I know of another car in my area it was a Y8 and now its a Y7, just opposite from me. It also has the same problem in same location on the rpms. He has no clue what it is and really not looking for an answer either, just drives it that way...so got to be more out there..

 

Is your car an auto? If not you can't use an auto ecu with the two wire IACV either way

 

car is an auto so whats the fix? does the y8 autos have three wire cause the y8 came out of a manual car with a two wire.
I can undo my conversion by adding a pin back into the mix. The loose pin I used for the knock sensor wire.

Do I also need to get an auto intake manny? if so can I mount up the y7 idle control crap cause I still have that stuff.

The car in the area with the same problem was a y8 now a y7. That car oddly enough is using a auto harness, manual ecu the forth connector is just not plugged in. It has had the two wire conversion too, but its a manual car.

 

yes auto y8's have 3 wire iacv's. if u make a block off plate or leave the 2 wire iacv on the intake manifold to keep the hole plugged you will be fine with no vacuum leaks. the 3 wire iacv is mounted on the t/b so you will NOT have to change the intake manifold. if your cars an auto y8 u need the 3 wire iacv there is no way around that.

 

so i need a Tb off a y8 auto to make it work? cause I dont see how it would mount up otherwise, or could I use the Y7 off the car originally? I know it wouldnt have as much HP but i want it to run smooth for now and I have that stuff.

 

t/b off a y8 auto or a t/b from a y7 will work as well. the y7 had the 3 wire iacv on the 5spd and auto. so reuse your y7 tb and fix your wiring back to the 3 wire iacv and see how that works. im sure this will fix your problem.

 

thanks bro the more we talk about it the more I think your right. I'll post back when I get it all swapped out to help others in the future if they make same mistake as me...

 

I guess as far as my friend running the two wire on the y7 manual tranny, y8 manual manny, manual ecu, auto harness...he needs a manual harness or swap tb and iac like me and convert his *** back to three wire cause of the harness?

 

go somewhere and get some codes pulled for that CEL.

 

if running a y7 5speed( no matter what transmission y8 or y7) he will need to run a 3 wire iacv like you have to. running the auto harness is ok. he should still have the 3 wire iacv plug i hope and didn't cut it off. he will just have a few extra plugs being its a automatic harness and an extra plug at the ecu. he can cut them off or leave them dangling it wont hurt anything. he needs to convert to a 3 wire iacv because the y7 ecu looks for a 3 wire iacv no matter if its a manual or automatic. the only time you need to do a 2 wire iacv conversion is when running a y8 manual ecu or if swapping to a obd1 ecu(those are all 2 wire iacv). hes needs to swap back because of the ecu not the harness.

 

codes were read as I detailed they said Icv failed circuit which all adds up now as I cleaned and verified it was working just not properly I assume since its an auto/two wire convrsn

or are you talking my friends car?

 

Yeah the IACV is is ECU specific. Y8 auto/Y7 auto and manual ECUs look for 3 wire.

 

both of you would need to swap to a 3 wire iacv with it located on the tb not the back of the intake manifold just leave the sensor there to keep it sealed off.

 

i plan on doing it tomorrow i'll post up what happens tomorrow night..thanks again fellows.

 

i swapped out to the y7 tb and repinned three wire. I neglected to clean out the IAC on the new tb I thought surely it would be ok, not. I started it and it revved all byself up and down from like 5-600 up to 2k. So I now have to clean out the IAC to see if that fixes the problem? So I'll let you guys kno if cleaning the IAC fixes it this time.