bdubnyc

I have a weird revving and idle problem...i just swapped a Z6 into my Hatch..and at start up i have a HIGH pitched whistle coming from my TB and while the car is cold the idle will bounce up and down up and down until its warmed up and once its warmed up it will calm down. also while its cold and has that bouncing idle if i put my finger over the upper hold inside the TB the Idle will drop and it will idle like normal...the moment i take my finger BACK off the top hole it will go back to having that bouncing idle until its warmed up.

ALSO about this weird revving...if i SLIGHTLY touch the gas pedal and SLOWLY rev the car and HOLD the gas pedal in a LOW REV the RPM's will bounce up and down while im holding the gas down SLIGHTLY! but it only does that in a LOW rev..i dont have a tach so i couldnt tell you what RPM its doing it at but it sounds pretty low..and if i keep pressing it down once i get past that weird bouncing rev it will clear up..what could that be?

I have cleaned the IACV and Tightened the FITV and also cleaned out my TB with Carb Cleaner but none of that helped with the crazy idle at start up and weird revving when i slightly hold the gas down...im stumped.

austinkli

welcome to another episode of the most common problem on h-t.

answer, it just does that man. some people will get on here and give you a ton of ideas, clean the iacv, play with the idle control, check your vacume lines, all kinds of ideas. and here it is, it just does that until it's warm. you only have a problem if it continues to do this after it gets to normal operating temperatures.

bdubnyc

oh ok the idle bounces really fast too lol thats why i thought it was a problem..

So now what about my other problem when i slightly rev the gas the idle jumps up and down while im holding the gas steady at a LOW RPM?

bdubnyc

BUMP for an answer..

So now what about my other problem when i slightly rev the gas the idle jumps up and down up and down while im holding the gas steady at a LOW RPM? then once i rev past that point it clears up.. it does it in neutral and while im taking off.

bdubnyc

Bump NEED SOME HELP!...also noticed that sometimes that weird revving will go away then come back later or if i turn the car off then on again.

AnotherSI

the bouncing idle when its warming up is most likely your fast idle thermo valve (or FIT valve). its located underneath your throttle body. there is a plunger in there that threads on to a rod that connects to a thermo spring. this controls the air flow past the throttle plate when the engine is cold. that is what the lower port in front of your throttle plate is. on the back side of the valve theres two phillips screws that hold on a cover plate. take the plate off and make sure the white plunger is all the way threaded in (clockwise). if it is then the valve is most likely faulty or there is a vaccum leak else where. now for the low bouncing idle... the upper port in front of your throttle plate is for the idle air control valve (IAC valve). i had this same problem and since im obd2 i dont have FIT valve and ended up having to replace the IAC valve. you can try cleaning if with carb cleaner and make sure the port is clear but there are no mechanical adjustments. hopefully this is of some use to you.

AnotherSI

im an idiot, didnt see the first time i read through that you said that you already tried adjusting the fit valve and cleaned the iac, sorry.

bdubnyc

Yea i tried cleaning all of those and the bouncing idle is still there its just not as long as it use to be and the bouncing idle stopped before it even warmed up one time..i think i may have low coolant since i just did this swap..

Now anyone have an idea for this problem???:

when i slightly rev the gas the idle jumps up and down up and down while im holding the gas steady at a LOW RPM? then once i rev past that point it clears up.. it does it in neutral and while im taking off.

AnotherSI

my 2000 si did the same thing with the strange bouncing low idle. i had a check engine light for it tho. after goin through all the flow charts for the code it came down to the iac was bad. i replaced and havent had the problem since.

bdubnyc

Yea i have a check engine light too and i thought it was because i didnt have an O2 sensor but i installed a new one and it still is up

I noticed that the Bouncing low idle when im revving the gas in low rpm will sometimes go away..i cleaned out the IACV cuz it was NASTY but it still does that...i just have to find the time to figure out what code it is throwing.

bdubnyc

Well since i dont have to work this afternoon im finally going to be able to figure out what CEL code im throwing....ALSO i just noticed i dont have a tranny ground..could that be a possibility of the Acceleration issue and bucking AND idle at start up? lol Where can i get a ground wire?

AnotherSI

i guess anything is possible, not to sure about whether it'll fix your problem but i'd just go to napa or some place similar and buy a battery cable with eye-loop ends. that'd work just fine.