1992 Civic
Hatch
DX
auto tranny
i/h/e

Alright, i have been having a ruff idle problem. When my car is warmed up and i pull to a redlight and stop, that car gets very shakey and the rpms drop and the engine lopes. Sometimes when a light turns red and i will coast to it will surge up n down 3 or 4 times then level off till i stop then it returns to the bad idle. The idle is a 80% occurence thing when the motor is pretty well warmed up usually.In the mornings the car had a crazy idle. I cleaned the TB, FTIV and IACV (i think those are the acronyms...)

NOW, the car idles perfect in all the gears and reverse but in N and park the car does the surge thing. I put the car in park and walked around and unpluged the IAC valve and it stopped surging but the idle hardly changed though. I pluged it back in and everything was normal no more surge. I left it running and went through the gears and then back to N and park and still it was good. I turned the car off and back on and there is the surging idle...

Does this mean i have a bad IACV? Im not sure because i read that if you unplug your IACV the idle should get lower and closer to normal, but mine just pretty much stays the same, and when i plug it back in the idles change and its normal untill i turn the car off.

 

Bump before work

 

http://www.ef-honda.com/ben/Badidle.php

 

My problem isnt described here and i have read 2 or 3 of these already. The IACV, FTIV, and TB where cleaned and i see no cracked hoses. I dont see what would cause the SURGEING idle. It will go up ~500rpm and drop and imediatly do it like (read slowly/normal pace) vroom vroom vroom exactly how you just read it. I know that sounds idiotic of me but im trying to give detail. It does it at the same rpm's too. It doesnt change.

 

the only thing that is left out of that thread is a chipped ecu. somtimes people burn programs and jack with the o2 and idle corrections.

if your idle is bad, it HAS to be one of the things mentioned in that thread. its gotta be. just has ta. soory i was no help.

 

You tried and was polite compared to most on here so your awesome in my book

besides, there a few things left i need to check so dont say you havent helped yet.

 

BUMP

 

wow...

 

It could be the O2 sensor is bad. I have the sme problem, and I think that the O2 sensor is causing it. Try changing that, and see is it works.

 

is there a way to test it before i replace...

 

Yes you need a Civic manual to know what to test for resistance on the wires. I'm at work, but I can post it when I get home and check the manual. But the O2 sensor controls the fuel, so if it is bad it could dilver the wrong amount of fuel durring idle, in turn causing a shaking, stalling idle. I belive this is my problem becuase I threw a code, the only problem is that I almost striped it trying to take it off so I have not be able to see if this is the fix I need. If you take it off make sure to get the engine warmed up and use a breaker bar or something becuase it is on tight!

 

Alright, im going to try this.

 

last thing you can try is check for a vacuum leak around the intake. Use a can of carb cleaner spray it around the intake gasket, TB gasket, fit gasket , hoses, and the iacv. if you have a vacuum leak the idle will change as it sucks in the cleaner. Also after the car wars up take the intake off and look inside the TB you will see 2 holes on the left inside the TB. cover the bottom hole with your finger if the is suction there the fitv needs replaced or repaired

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by instructor74 &raquo;</TD></TR><TR><TD CLASS="quote">last thing you can try is check for a vacuum leak around the intake. Use a can of carb cleaner spray it around the intake gasket, TB gasket, fit gasket , hoses, and the iacv. if you have a vacuum leak the idle will change as it sucks in the cleaner. Also after the car wars up take the intake off and look inside the TB you will see 2 holes on the left inside the TB. cover the bottom hole with your finger if the is suction there the fitv needs replaced or repaired</TD></TR></TABLE>

Alright i looked up and found another FAQ but its kind of confusing. The bottum hole only sucked when the engine was cold. After warming up it didnt. Thats good news. I reved up the engine and when it dropped it did the surging. I covered both holes and the surge stopped and the idle leveled off. Bad IACV?

 

sounds like you found the problem all things are pointing to the ivac being bad

 

just wanted to make sure.

 

Im glad that you discovered the problem, I'm going to try that and see if it is the same thing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hex420 &raquo;</TD></TR><TR><TD CLASS="quote">Im glad that you discovered the problem, I'm going to try that and see if it is the same thing.</TD></TR></TABLE>

thanks, i replaced it and everything is good.