95 GSR engine in a 95 Civic. Car would idle at 3K and bounce down 1500 and repeat. I noticed that when the car was warmed up, the little hole inside the throttle body (one on bottom, not top) was still sucking in air. When I covered it with my finger, the idle would return to normal. So I went to Acura and bought a new Fast Idle Thermo Valve part #16500-P72-000 and paid $87 Replaced it and 10 minutes later problem solved. Just wanted to inform some people who have this same problem

 

any idea if there's a fast idle valve on a 99 SiR? coz i don't see something like that under the throttle body.

 

The '99 SiR does not have a FITV.

Another alternative to replacing the FITV is to take it apart and screw the thermowax plunger back in. It tends to back out over time and cause the conditions you described. This is a common problem that has been occuring since '94-'95 when they started using FITVs on the GS-R TBs (among other TBs).

-kenji

 

I had a similar problem when using a P28 based Hondata...we reduced the IAC duty cycle and saw the surging disappear.

Austin

 

i have a jdm b16 in a 95 civic and my idle bounces from 700-1500 constantly, could i have the same problem as him??

 

i have been putting this off for a while because I hate to throw parts at a car to make it run right. I guess this will be my next "mod" hahaha.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CivicEx95 &raquo;</TD></TR><TR><TD CLASS="quote">95 GSR engine in a 95 Civic. Car would idle at 3K and bounce down 1500 and repeat. I noticed that when the car was warmed up, the little hole inside the throttle body (one on bottom, not top) was still sucking in air. When I covered it with my finger, the idle would return to normal. So I went to Acura and bought a new Fast Idle Thermo Valve part #16500-P72-000 and paid $87 Replaced it and 10 minutes later problem solved. Just wanted to inform some people who have this same problem



</TD></TR></TABLE>

i have the same problem but the top hole is the hole that is sucking in and even when i cover it up, it still surges. what should i do?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by redVtec21 &raquo;</TD></TR><TR><TD CLASS="quote">

i have the same problem but the top hole is the hole that is sucking in and even when i cover it up, it still surges. what should i do?</TD></TR></TABLE>

Strip the paint/putty off the idle adjustment screw, and adjust idle as per Helm's instructions. Most of the time there is too much/not enough air moving through the TB's holes or a vacuum leak of some sort. That will make the IACV constantly hunt for a good rpm (thats the top hole), and cause surging during idle. The FITV is the other cause. I tried to do that on my last car, and a screw broke Surged till I replaced the TB.

 

aight thanks ill try that

 

OBD2 GSR motors dont have that.

 

ooh man i cant believe you bought that.. i had this problem i just took out the valve and put a piece of foil between that and the tb and rerouted the coolant lines.

 

if you notice in your second picture,
the white thingy inside the FITV, that is way too high which cause the high rpm surge. If you take a look at the left, there are two screws there in red, unloosen those and take everything out from in it and clean it with carb cleaner, after that becareful where each part went and tighten up the white thing almost to the bottom facing the blue arrow. Finally cover up the top portion and screw the red bolts back in where it belonged. That shouldve solved your problem and saved you lots of money. This has also been covered pretty well.

 

^^yes I had a surging idle problem on my b16 too, I took off that little plate cover, and tightened down the plunger with a quarter or a dime.... problem solved, total cost 5-10 mins of my own time and a bit more than that in reading

reading FTW. It can save you lots of money

 

so what about B16s that don't have FITVs?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ziich2 &raquo;</TD></TR><TR><TD CLASS="quote">so what about B16s that don't have FITVs?</TD></TR></TABLE>

what about them?

 

how do you fix the surging idle?

Checked for vacuum leaks and bled the coolant, but don't think it's either of these because it only surges while warm. Also you can feel the motor surging while driving. In lower gears it will actually accelerate on it's own, sometimes in a fluctuating manner, sometimes constant.

65mm edelbrock throttle body
removed cruise control and plugged up the vaccuum holes

I've been trying to solve this problem for months and just gave up for a while. I'll give a cookie to anyone that can figure it out for me though.

 

Newer cars have the function of the FITV is built-into the newer type IACV. Do you have a mixture of (for example) new throttlebody (without FITV) along with older IACV?

 

First, check for vacuum leaks, including Intake manifold gasket leaks. Then check to make sure that there is about 1/4 inch of slack in the throttle cable. Then you will probably want to set your base idle. With the engine warm, unplug the IACV and set the idle to between 450 and 550 RPM. Kill the engine, plug the IACV back in and clear your ECU memory. Crank the engine and let it idle until the ECU settles down and you should be idling around 750 RPM. Any excess air that enters the motor can cause this idle surge. Vacuum leaks, IACV, FITV, EGR not seating when closed, bad PCV, throttle cable too tight, and idle screw out too far can all cause a high idle. When the idle exceeds ~1200 RPM with the engine warm and the throttle plate is closed, the ECU cuts off the fuel injectors. The idle falls below the threshold, the injectors cut back on and the whole cycle starts over again.
IACV's allowing too much air to pass can cause the problem, but the IACV is not what is cycling the idle. Anything that has a vacuum line running to it is suspect and must hold vacuum including the cruise control, MAP, IAB, and boost valve, if equipped with any of these.