Flat Spot in Almost Idle
 

I am tuning a y7 with a y8 intake. Xenocron Conversion Cable and a P06 Converted to VTEC. 2 problems.

1: with the IACV connected the idle Sky rockets to 2800-3000rpm, hooked the IACV driectly around the Converison Harness and get the same thing. Try a z6 and a ls iacv.

2: With the IACV disabled the car idles a little High, no big deal, but it has a surge like sitting on a launch control from 1600-1800rpm. It revs fine, no other problems but this. We had the car running for 1 week with the IACV disablr and it had the same thing..

Any insight, We assume the surge is due to no IACV, but I have used the script sucessfully before on another y7.

Re: Flat Spot in Almost Idle
 

This is in Crome?

What car is this? Did it come with a 3-wire IACV and you converted the wiring to a 2 wire and used the Y7 manifold for that correct?

Disabling the IACV in Crome only really disables the CEL for IACV...the CEL still resides in the computer and 'weird' things can still happen. This is probably whats causing your weird studder down low...they are working on disabling the entire routine, but who knows how far that is off...

Re: Flat Spot in Almost Idle
 

That's exactly what I'm getting, iddle at 1500-1600RPM when cold and flat 1000 when hot (sometimes it goes back to 1500 for no reason)
like xenocron said, i get some studder at low rpm. I don't have problem on highway or when accelerating. But its a real pain in the ass trying to maintain a low speed in a city or traffic jam.

Re: Flat Spot in Almost Idle
 

Crome Registered
99 DX Hatch. y7 motor that had the 3wire IACV, tossed ona y8 mani and LS or Z6 IACV, took B6 and moved to to B23 (If I remember correctly) and disregarded the orange wire.

Ya I know it only disables the CEL. I'm going to try a Uberdata map for the hell of it to see how te idle respond to that.

But any ideas why the IACV cause the 2800-3000rpm idle? I thought I wired it wrong so that is why I traced it to A5 on the OBD1 Harness and jumpered it directly to that. IACV duty and such is what ever Crome makes it from the start.

Re: Flat Spot in Almost Idle
 

Make sure the one wire is feeding the IACV 12 volts, the other goes too...hrm, ---- I forget, probably ground.

Re: Flat Spot in Almost Idle
 

i have a bouncing idle as well. -> y7/y8 mini-me using the two wire iacv. i did the mini-me first before i boosted and the car ran 99.5% fine on the stock p2p ecu.

then i boosted it and swapped in the p28 with an uber chip and the idle bounces and also have some odd fuel cut or something at part throttle.

swapped in a vafc for inspection and the bouncing idle was gone and most of the odd fuel cut aswell.

im now setup to tune with crome so i'll see if i can get rid of the bouncing idle. but it looks like its really just a rough map and needs a good tune.


yours might be a similar problem?

Re: Flat Spot in Almost Idle
 

We fixed this. It was the IACV being disconnected.

Re: Flat Spot in Almost Idle
 

good to hear you fixed it. and thanks for posting the resolution as well :)