hey guys iv read a couple of the threads with ppl having the same problem as i am and tried them all and it keeps doing the same thing i have a 90 accord lx coupe iv changed the spark plugs and wires, cleaned out the IAV and the FITV both were pretty dirty and reset the ECU, but still no luck every time im slowing down to a stop sign, light or even parking it idles so rough that it feels like its goin to stall but when i have my AC on itll stall everytime i slow down. It starts to happen when im little below half a tank, when its full runs like a champ. i hope its not a fuel pump job anyone got any suggestions pllz i need it fixed

 

I have always thought that was normal for these cars. My '93 has always done that, not that I like it, it just has.

 

but it never did that before 2 months ago it sucks but i was reading some more forums and i never adjusted the FITV i just cleaned it out and how can i diagnose the IAV and FITV to see if they are working or not

 

I had the same problem with my 91' It turned out to be the ignition coil. Might wanna check that. Good Luck!

 

If the Idle Air Control Valve (IACV also called EACV by Honda) fails (open in drive solenoid), cleaning will not help. The IACV provides air for idle and must work to have a stable idle.

Check IACV coil for function by applying 12v and ground directly to coil connector. It should move the IACV to open position and valve should close by spring return as soon as voltage is removed. If IACV checks OK, check for voltage to the IACV. You should see 12V on the Yel/Blk wire to the IACV. Ground is supplied or denied by ECU to control IACV open time and idle speed.

Did you clean throttle plate (both sides) and throttle bore w/ throttle body cleaner? This must also be clean to allow good idle.

good luck

 

i think the iacv is workin cuz when the car is running i unplugged the IACV it idle very low and the check engine light came on and i cleaned the area where my cold air intake was the two little holes that lead off to the IAVC and the FITV i sprayed in them, where is the the throttle bore located is that inside the throttle body inside the throttle body plate thanks guys so much

CRACKED im going to change out my ignition coil next check and see if thats the problem THANKS

 

Check for air in your cooling system. That can confuse the idle-control system when it goes thru the FITV and/or IACV.

How low does it idle when you unplug the IACV? It should be somewhere like 550 rpm.

 

i bleed the cooling system already so that's OK, yea when i unplugged it drops around 550 rpms and the check engine light comes on then when i plugged it back in then it started to hunt for the idle up and down over and over again can it be the ignition coil like cracked posted earlier in the post
thanks for the quick response

 

For 1990, there's also an air boost valve #9 that can allow excess air into the intake manifold. I never had a Honda with that component, so I don't know what to do with it, other than clean it??


I actually looked back for where you said your coil was cracked. You're talking about user "crack3d", right? Or does YOUR coil have cracks? Cracked coil can produce flaky spark, and it can cause this. You can check by starting the engine in complete darkness & watching for arcing. This works best when the engine is completely cold before you start.

Idle RPM hunting up & down (but not misfiring) would make me suspect IACV, FITV, boost valve, etc. - components in the idle control system.

Misfiring (caused by coil or wires etc) is a sharper drop in RPM, & it sounds different in the exhaust. Sorta hard to describe in words.

 

i had a small leak by my headers and it was throwing off the o2 sensor it will show a code for the check engine light saying fuel too lean