This will be my last thread I make about this. I am hoping this will be resolved, because this **** is driving me nuts. I made this thread so new people wont have to read thru 10+ pages.

Scenario:

I have a bouncing idle. It goes from 1800 to 2400 over and over. When I start it on a cold start, the idle shoots to 3000 or 4000, stays there for like 4 seconds, and then drops down slowly to 1800 then the 1800-2400-1800 cycle starts.


Things tried:

New PCV valve
New TB gasket
New Intake Manifold Gasket
4 different IACV's

The car is a 97 hatch 5spd. The motor was from an automatic d16y7. I dont know if the dude used the auto motor harness, or the 5spd. I now have a 5spd throttle body on it.

I try to cover the throttle body completly and the idle lowers down quite a bit. It stays steady for a moment, then bounces, stays steady, bounces..etc. prior to that I had the battery disconnected, and even pulled the under hood "backup" fuse.

I am willing to send money to whoever can diagnose and help me fix this problem.

by the way, my IACV is on the tb. not the back of the mani.

 

- engine running, unplug the iacv; what does the idle drop to? should drop to 550-600 rpms, if not adjust the bleed screw to those specs.
if idle dont go down low even with the iacv unplugged you most likely have a vac leak

 

Ind if you have a vac leak, the easy est way to find it is to take something like starter fluid or brake cleaner, spray it around a suspected leaking hose or gasket etc and listen for a change in the engine speed.

 

i tried spraying all over. i cant find the leak with carb cleaner.


and when I unplug the iacv, should the car be warmed up already

 

check this out, when i move my finger around the base of the TB i can hear a sucking noise when im over a certain part. its like right underneath my iacv but on the base of the tb

 

Are you missing the fitv (fast idle thermo valve)?

Your iacv isnt suppose to be on the bottom of the tb. It's either on the firewall or on the back of the intake manifold iirc.

 

if he would be missing either the iacv or fitv the car would idle at like 3k rpms..
some plenumless engines have the iacv on the tb

 

ok I have OBD2 SO I HAVE AN IACV not a FITV so yes my **** is at the bottom of the tb

 

bleed any possible air bubbles from the coolant.

To everyone busting his *****, d16y7 throttle bodies had the IAC mounted to them.

OP: you might want to look into a d16y8/d16z6 intake manifold and a new throttle body w/ fitv. (pick and pull y0!)

 

no thanks. I dont want a y8 mani. been there done that. i get better mpg's with the y7.

also, i bled all air from coolant.

i found the problem to be the autozone tb gasket doesnt cover the tb fully, like the oem gaskets do. so tuesday my local stealership is getting one for me