When i first start the car, i noticed that the car is struggling to idle than it will come to life and revs to 1700 rpm or so but secs later, the idle will drop to like 1200 and i can hear the motor trying to stay idle. It will fluctuate from 1200 to 1700 back and forth while i can hear little "pop" noise from the exhaust. It definitely sounds like i am running rich. I beleive my FITV is bad on my 94 GSR and is not letting enough air in causing the car to choke/struggle to stay idling. Once the car warms up, it drives fine.

I have been researching and i "thought" you can clean the FITV but it doesn't seem that way. You can only clean the IACV with carb cleaner. Am i wrong? If so, i have heard of people bypassing the FITV but wouldn't this cause the same problem if the valve wasn't working properly? (if the valve is stuck closed, no air will get through. If i plug up the holes, it seems like i am doing the same thing as a plugged valve) Anyhow, i know the ITR or later model tegs don't use this mechanical valve but how do they run operate the cold idle? I am currently using a JDM ITR ECU if that will help. Any thoughts? I really don't want to spend the money to buy a new FITV. Thanks.

 

When did this problem start occuring? Did it do it right when you put the ecu in?
I have a similar problem, but because my car was an auto 94 LS and I converted it to a manual obd2 ls motor I no longer have the FITV and I am using the auto ecu.

I have tried checking everything and people told me its the ECU causing the problems now and I think that it could be because I no longer have a FITV. I think you can clean the FITV though and somewhere there is a post about adjusting the FITV. I was just suggesting that maybe the ECU could be affecting the idle.

 

First thing to do is test it.

Warm up the car, take the intake off, and let the car idle. On the TB, there are two holes, cover up the lower hole on the inner lip with your finger. If the idle dies down and almost stalls, your FITV is bad.

If thats the case, pop it off...its 3 10mm bolts. When you see the valve, its a long bolt inside...try and turn that bolt all the way until its fully compressed. If it wasnt, try popping it back in and see if that fixes it. If it doesnt, you can either replace the valve, bypass it, or cover up the 3 holes. Either plug them with some sort of caulk or filler, or duct tape the entire top part. Use something that wont melt....a sheet of vinyl works.

Pop it back on and your idle problems should be fixed.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bitzbp &raquo;</TD></TR><TR><TD CLASS="quote">When did this problem start occuring? Did it do it right when you put the ecu in?
I have a similar problem, but because my car was an auto 94 LS and I converted it to a manual obd2 ls motor I no longer have the FITV and I am using the auto ecu.

I have tried checking everything and people told me its the ECU causing the problems now and I think that it could be because I no longer have a FITV. I think you can clean the FITV though and somewhere there is a post about adjusting the FITV. I was just suggesting that maybe the ECU could be affecting the idle.</TD></TR></TABLE>

This happened when i pulled my car back out of storage this year. I was stupid.....only started my car once throughout the whole winter and maybe because of this, my FITV went bad. It's not the ECU for sure because i have had this problem even when i was running a P72.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by newgsrdriver &raquo;</TD></TR><TR><TD CLASS="quote">First thing to do is test it.

Warm up the car, take the intake off, and let the car idle. On the TB, there are two holes, cover up the lower hole on the inner lip with your finger. If the idle dies down and almost stalls, your FITV is bad.

If thats the case, pop it off...its 3 10mm bolts. When you see the valve, its a long bolt inside...try and turn that bolt all the way until its fully compressed. If it wasnt, try popping it back in and see if that fixes it. If it doesnt, you can either replace the valve, bypass it, or cover up the 3 holes. Either plug them with some sort of caulk or filler, or duct tape the entire top part. Use something that wont melt....a sheet of vinyl works.

Pop it back on and your idle problems should be fixed.</TD></TR></TABLE>

Thanks! GSRdriver! I have searched through this topic here on HT and it seems you know alot about this problem! I will check the valve to see if that is causing my bad idle. Once again, thanks for the help!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">First thing to do is test it.
Warm up the car, take the intake off, and let the car idle. On the TB, there are two holes, cover up the lower hole on the inner lip with your finger. If the idle dies down and almost stalls, your FITV is bad.

If thats the case, pop it off...its 3 10mm bolts. When you see the valve, its a long bolt inside...try and turn that bolt all the way until its fully compressed. If it wasnt, try popping it back in and see if that fixes it. If it doesnt, you can either replace the valve, bypass it, or cover up the 3 holes. Either plug them with some sort of caulk or filler, or duct tape the entire top part. Use something that wont melt....a sheet of vinyl works.

Pop it back on and your idle problems should be fixed.</TD></TR></TABLE>


OK...i just checked that. It's fine......when the car was warm, i undid the intake tubes and covered the lower hole....nothing. There was slight suction but the car didn't die on me. HOWEVER, when i covered the hole on top, the the car almost stalled out.

Something in your test doesn't make sense.

The lower hole in the Throttle body is for the FITV, and when it's fully warmed up, it should be CLOSED meaning if i put my finger over that when the car it's warm, it shouldn't stall out because it shouldn't be getting air in there from the first place. Is there something that i am missing? Because based on this website,

http://webpages.charter.net/mr...1.jpg

There should be suction when the car is COLD and there should not be suction when the car is WARM. Did you have your logic reversed?

EDIT: I tried cleaning my IACV tonight and it didn't help. Also, when the car is cold, there is ALOT of suction coming from the lower hole of the inner lip of the throttle body so i think my FITV is working as well....shitty.....more digging to do.


Modified by eg-six at 5:00 PM 6/15/2003


Modified by eg-six at 6:53 PM 6/15/2003

 

Your IAC valve could just be bad. Often they're just dirty so cleaning out fixes the problem. Easiest way to tell is swap in a 'known-good' IACV. But you have to find a known good one...

I suppose you've already checked for dirty/corroded electrical connection to the IACV?

 

I think it should be warm. I remember doing the test when the car was warmed up.

You get the gist though, try it when its cold then. It shouldnt STALL, it should die down and stop bouncing so violently. There should be suction...not enough to yank you into the engine bay, but enough to suck your finger in the hole.

When you covered the top hole, did you 100% completely cover it? If so, under normal conditions the car should stall. If the idle still bounces, the IACV is bad.

Did the idle change at all when you covered the lower hole?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by newgsrdriver &raquo;</TD></TR><TR><TD CLASS="quote">I think it should be warm. I remember doing the test when the car was warmed up.

You get the gist though, try it when its cold then. It shouldnt STALL, it should die down and stop bouncing so violently. There should be suction...not enough to yank you into the engine bay, but enough to suck your finger in the hole.

When you covered the top hole, did you 100% completely cover it? If so, under normal conditions the car should stall. If the idle still bounces, the IACV is bad.

Did the idle change at all when you covered the lower hole?</TD></TR></TABLE>

When the car is cold:

Covered the lowerd hole, LOTS of suction and the motor almost stalled!
Don't think i covered the upper hole

When the car is hot:
Slight suction from the lower hole.....motr idles fine even with it covered.
When i covered the upper hole, the motor wants to stall, LOTS of suction.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eg-six &raquo;</TD></TR><TR><TD CLASS="quote">
Slight suction from the lower hole.....motr idles fine even with it covered.
</TD></TR></TABLE>

Motor idles fine meaning ~750RPM? Fine meaning not bouncing?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by newgsrdriver &raquo;</TD></TR><TR><TD CLASS="quote">

Motor idles fine meaning ~750RPM? Fine meaning not bouncing?</TD></TR></TABLE>

Yeah.....around that. Not bouncing, smooth just like it's suppose to.

 

So when you cover the lower hole, the motor idles smooth.

Then your FITV is bad

Next thing to do would be to pull it off and see if it just needs to be closed. Once you take off the valve, youll see that you can turn the bolt inside of it. Make sure its all the way tightened.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by newgsrdriver &raquo;</TD></TR><TR><TD CLASS="quote">So when you cover the lower hole, the motor idles smooth.

Then your FITV is bad

Next thing to do would be to pull it off and see if it just needs to be closed. Once you take off the valve, youll see that you can turn the bolt inside of it. Make sure its all the way tightened.</TD></TR></TABLE>

But the motor idles fine to begin with. Only in the cold is when the car is having a hard time idling. I think it's running too rich. And when i plug that hole if the motor is cold, it wants to stall out!

 

It sounds to me like your FITV is OK. When the engine's warm, it isn't supposed to make any difference when you cover the port. Sounds like that's the case. The tiny bit of suction doesn't worry me too much. Take off the valve & check it out, but I don't think that'll fix your cold idle.

If it idles OK when warmed up, then maybe your IACV is OK, too. Try turning all kinds of loads on & off, like fans, lights, & AC. Your idle might be disturbed slightly, but then recover quickly with the load still on. If so, your IACV is working OK, at least when it's warm.

Why do you think you're running rich when cold? Actually, it's supposed to run richer when cold, just not too rich. That's pretty vague, huh? Take out your spark plugs & read their condition. They might show something.

So what about other stuff? How old are the plugs? Wires? Cap&rotor? I've seen bad plug wires cause stuff like that when their insulation breaks down. Your spark leaks to ground, then when the wires warm up they're OK. Let your engine get stone cold, after dark, take off your sparkplug cover, turn off all the lights. Start the engine & look for arcing.

 

I think youre misunderstanding here...

When you plug the lower hole, the car should die down and *almost* stall. It should sputter....idle at low RPMs. It should NOT surge. If you plug it and thats what happens, the FITV is bad.

I dont remember if its warm or cold, and honestly I dont think it matters. I did mine not fully warmed, but not ice cold. It was warm.