This is probably the billionth thread on a up and down idle but fellas; finished the manual swap, and now i have a bad idle.

I have the manny ecu installed, did all the required wiring. But the car starts to about 3000 rpm, hangs there, the goes down to about 1000 then to 2000 rpm over and over again. Frankly its getting demoralizing.

as any other i suspect the iacv. I did install the manny Intake manifold and throttle body too btw. First vacuum leak i found were the fuel injector seals. Did the carb cleaner trick while it ran and it was an easy fix. But i started rhe car and still same thing. Did an idle relearn. Started but idled on the bottom line like it was about to die. Then the idle start to yoyo again after i turned it off and on again.

Took off the intake and put my hand over the throttle body and the engine died. So no vacuum leaks right? But im kind of a noob when it comes to vacuum.

Any clues perhaps? Or any link to a good idle diagnoses? Thanks in advanced.

 

I searched "manual swap idle" and came across a thread mentioning two identical plugs for the IACV, one of which is for the IACV and one of which is not. Does your harness have two connectors like that?

Do you have any codes/CEL? Sometimes that'll narrow it down, even in a weird and roundabout way.

 

Yeah i saw that aswell but the wires on my harness seemed to just land where they previously went for the most part. But i will see if that works just to narrow it down.

Also, no check engine lights. Last night after a idle relearn it idled at about 100 rpm. I unplugged rhe iacv and adjusted the idle screw to about 500 rpm and it runs fine. But every single start the rpm jumls to 3000-3200 rpm and then goes back to the 750 then to 500 rpm. That would still mean i have a vacuum leak somewhere right? Im fustrafed because while running i spray carb cleaner on the top and sides of the IM gasket and theres no change in idle. Sprayed pretty much all around he IM. And its hard to spray under the IM if that would even be the problem. Iacv is clean and the coolant is bled.

 

Used a scanner while car was running. Throttle position is at 9.2 while idling.

 

While running rough i disconnected the iacv and the idle went to normal idle. Even turned it off and on withought the iac connected and started normal, shot uo to about 2000 rpm then slowly went to the normal mark on the tac. Could be my iac then? I did buy a cheapo like 50 bucks haha

 

So I broke out my service manual for a 1994, and it looks like it might be your FITV if you haven't checked that guy out yet.

 

Its a 96 ej8, they didnt come with fitv

 

Ah ****, probably should have asked that first. I can send you the service manual stuff for the 96-98 as well if you'd like, but the long & short of it is that you should probably start with swapping in a known-good IACV and seeing if that fixes it. If it does, great, and if it doesn't, at least you can cross it off the list.

 

I'll see about that.

Yeah if the manual has a diagnose procedure that would be great actually. Thanks.

 

Goddammit it was the freaking cheap iacv. Thought i could skimp out on it. Nope. Dumped a good chunk of money on one at my local oriellys and it turned on like it used to as an automatic it was so beautiful. Now to learn how to drive stick. Thanks guys, 'appreciate the help! Best community ever man lol now i'm officially manual swapped.