Hi i have a 99 SI with a 95 jdm gsr motor.
when cold it idles around 1500rpm, stable, until i touch the throttle and it'll start bouncing from 1100 to 1500rpm. i've also notices when i change gear the car will rev a little higher before dropping.
When i disconnect the IACV it idles perfect. right at 750rpm. although it drives horrible, all jerky so i connected it back.

Any ideas of what it could be?

 

clean the IACV

 

i did it 3 times already, i have a feeling the iacv itself is bad, is there a way to test it?
i dont want to pay 215 for a new one and it not be the problem.

 

iacv are very interchangeable if it is that hit the junk yard. I doubt its bad.any recent work done before this happen.

 

no ever since i bought the car its done it, i put skunk2 intake mani on and its the same problem. every now and again the problem will go away.

 

Bump

 

check for vac leaks

 

I think if i had a vac leak it wouldnt idle perfect with the iacv disconnected. Right? And when i cover the hole in the throttle body for the iacv it idles fine. Im gonna try a used iacv.

 

You don't mention how it idles when warm. When you disconnect the IACV, the motor should stall or the RPM's should drop too low. Check the ignition system. If the ignition is fine, try closing the idle screw a little. If that doesn't work, try covering up the FITV hole in the TB with a piece of masking tape. Clean the surface with alcohol before applying tape. When did this problem start?

 

If none of that helps, check the MAP sensor voltage.

 

its when its warm it does the bouncing. when i disconnect the iacv it stops bouncing and idles around 750rpm. what part of the ignition system? spark plugs, wires and dizzy cap are new. the idle screw is almost all the way closed. throttle body doesn't have an fitv or a hole for it. it does have the iacv hole though, and when i cover that the idle regulates.

the problem has been on and off since i bought the car.

 

Don't cover up the hole with tape. The tape can eventually go into your engine. Do this instead:

https://honda-tech.com/forums/acura-integra-6/%2A%2A%2A-how-%2A%2A%2A-clean-your-fitv-aka-fast-idle-thermo-valve-1564019/

 

i have a 95 motor. no FITV.

 

Are you sure? Cause 96+ no longer have FITV. I have a 94 JDM motor and I have a FITV.

 

If the surface is cleaned well with alcohol the tape sticks to the point that you'll have to clean off leftover adhesive when the tape is removed. The suction from the hole also makes sure it stays in place. But it's a moot point with no FITV.

To check the whole ignition system you disable the injectors and get a new or known to be good plug. Wear gloves and carefully hold the plug with pliers that have an insulated grip. Connect each plug wire to the spark plug in turn while holding the threads of the plug against a bare metal (unpainted) part of the valve cover. Have an assistant crank the motor just a little while you carefully watch the spark. A strong spark will likely have blue sides with a bright pink center. If all the sparks are weak (and the start/charge systems are good), the problem is most likely either the coil, the ground or the cap/rotor. If only one or some of the sparks are weak then the problem is probably either the wires or the cap.

GL

....mmmm chewy pink center

 

i was told it was 95, never actually checked into that though, but it definatly doesnt have the fitv.

is it really possible that i have ignition problems? car runs strong for what it is. this is the only problem i've had with the car since i bought it.

im gonna try bleeding the coolant in the morning and see what that does, someone said something about air pockets being stuck in the iacv can cause an idle surge. this sound like it could be going somewhere?

 

check your gaskets, with the IACV disconnected the car should idle at 450 rpm if slightly above that you can adjust via the idle adjustemnt screw. if you can't get the idle down to 450 then you have a leak somewhere.

seems like there have been about 5 people on here today with idle problems.