idles rough when coming to a stop
 

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??
http://www.hondaautomotiveparts.com/...13SM20_E01.gif

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 the same problem with my idle
 

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

Yeah, exhaust leaks. Some background for that...
The O2 sensor actually measures the DIFFERENCE in oxygen from inside vs. outside the exhaust pipe. If you have an exhaust leak, blowing onto the OUTSIDE of the sensor, that'll throw off the measurement.

Just got mine back today for the same reason! Ignition coils aren't often checked, but warm stalls, (highway/rolling, or stopping) is often result of this. Get that checked. or check it yourself if you know how!

yes i was quoting CRACK3D about the ingition coil hopefully when i buy it this weekend thatll fix the problem. but there are some other things that happening when coming to a stop car starts to shake i think i might need to resurface the rotors and squeaking from the rear passenger side tire everytime i hit a bump think its the bushings thank you guys so much for you guyss help

hopefully this weekend ill find out thanks

how will i know if there is an exaust leak i know it sounds deeper and wierd but i got a flowmaster in my car so everything sounds deeper

listen by the headers for a kinda spitting sound or feel around them for air. also u can smell exhaust more than another car.go to auto zone have them tell u wut ur check eng code is reading, its free, itll say fuel too lean. u could try seafoam its at any autoparts store for 8 bucks itll burn out all the bad **** in ur engine it smokes out thru ur exhaust ull c where its cuming from. ull get back sum lost hp from over the years i did mine huge difference 270 000 mi still strong

Eddie C has a 1990 (right??) so AutoZone can't read codes. Jumper the SCS connector & watch the CEL flash out the codes.

yep its 1990 they only read it from 95 or 96 and up i jump it with a paper clip correct

my b i have a 96 idk jus try the sensor dude

well guys its not the ignition coil just changed it with a brand new one and a new rotor (had to break the old one off it was stuck badly) and its still idle rough but not as bad i can hardly feel the car shake but looking at the rpms it drops past 600 then jumps back where its supposed to idle at

next is exaust leaks if i was to buy the seafoam will it smoke out where the leak is comeing from and can i just pour it in with my regular motor oil with no problem

yea 1/3 in gas, 1/3 in oil, then the last 1/3 in the vaccum line slowly while the car is running it will sound like its going to die when it does let off on the pouring then continue you might need someone to giv it a little gas so it doesnt keep cutting off when ur pouring. then turn it off for 15min. then start her up and hold it about 2500rpm until the smoke is gone directions are on the bottle. u will c the smoke it will clean out all the junk in ur exhaust pipe it will look like oil dripping but its not just gunk then change your oil after 100 miles u will tell a difference

Another way to look for exhaust leaks...
Engine idling - have someone hold a wadded-up rag against the tailpipe. Don't seal it off enough to stall the engine, just raise the back-pressure. That'll make any leaks get louder & easier to find.

how can i check the computer of my car (90 accord) with the paper clip to see if its showing the code of the o2 sensor were is my ecu located and how do i place the paper clip im goin to try that seafoam thing this weekend and the rag trick to see if it gets loader and i guess i gotta clean the IACV and the FITV because its starting to hunt for idle again

there is a blue two-pin connector that is behind the passenger kick panel. Short the connector with a thin paperclip. Turn the key to the II position. Count the LED flashes on the ECU.

The ECU is on the passenger side towards the firewall. I think you just have to pull back the carpet. See Misc. Details on http://techautorepairs.com/ecu.html

The 90 accords don't flash the code via the CEL like the site shows.

well i tried to do it but it just lit up the check engine light no flashes in the dash nore the ecu and i think i found out y is idleling rough for but i wanna ask you guys before

i found a very small leak in one of the hoses connecting to the FITV were the radiator fluid is supposed to be flowing threw the thing is its kinda of yellow gunky stuff kind of hard to explain is it supposed to be that cooler and gunky i wiped it off yesterday 9/27/09 and today there was alittle bit on it its kind of hard to see because its on the bottom of the hose i just wiped with my finger and there it was any ideas thanks again

do you uys think that the leak in my hose connecting to the FITV can cause it to idle rough when coming to a stop

FITV can cause the idle to surge up & down, if that's what you mean by "rough". The normal warning is that air in the cooling system can confuse the idle system. But if there's crud in the FITV, or leaking, or stuff like that can probably cause it to act strange too.

Take off the hose, take off the FITV, clean it up. Remove thermostat & rinse out the cooling system real good.

Maybe you need to go over the idle control system & set base idle & all that stuff?

well its still cutting off on me if i press the brakes hard when im passed the half way mark if i let go of the brake on time itll idle rough (below 500rpms) and go back to its regular idle position now im guessing its not the iacv or the fitv at all any suggeestions and i changed the spark plugs, spark plug wire, rotor, ignition coil, fuel filter valve cover gasket basically every tune up i can and its still doing it plllllzzzzz help its getting annyoing

anyone plz