cstone

so, i have been fighting with a seemingly extra weird hunting idle for a few months now. when i first start the car it will never hunt unless i press on the throttle. if i stop just right, by taking it out of gear while coasting in 4th gear at 30mph (this is about 1500 rpms which is where it likes to idle most of the time, and btw it will keep going 30mph unless i press the brake or the clutch i dont even have to be touching the throttle) it will not hunt sometimes. the two things that seem to always cause the idle to hunt are 1.) driving above 55mph then slowing down. 2.) taking it out of gear with the rpms either above or below 1500rpms. well anyways being able to use a type of "cruise control" below 35mph is great and all (if you are confused try turning on CC when driving less than 35mph, in my car it wont engage so i think that is how they all are) but i would like my car to idle at the correct speed and not hunt. the hunting idle annoys the hell out of me, its pretty embarrasing, and very inconvenient considering i cant even go through drive-thrus because the person on the other end cant hear me over my car most of the time. also i know that idling at twice the recommended rpms isnt helping my MPG considering almost all of my driving is stop and go in town.

i have cleaned the IACV twice now (the first time because i thought that was the only problem. the second time was today because obviously the first try didnt work so i decided to tighten the FITV and while i was at it re-clean the IACV.) i did that today and so far both times it has fixed it for the test drive i always take when i do anything to my car. but as soon as the car cools down and then i start it the hunting throttle is back. when i cleaned the IACV this time it did have a little bit of build up but by no means was it even close to as dirty as last time. i guess my next step is to take them both off again and spray out the TB through the intake with some carb cleaner and take a toothbrush to the butterfly.

my question for you guys is i believe my thermostat is stuck open as the car will only warm up while it isnt moving. if the car is running while parked the temp will go up to about a quarter of the gauge slowly but when driving (even slowly through town) it drops below the lowest mark, like when the car is turned off. also the heater doesnt work very well when i am driving but gets pretty warm when it is parked. could the thermostat have something to do with my hunting idle?

GlassJAw

Have you bled the cooling system of air - air bubbles can cause fluctuations in temperature and also cause a hunting idle as the FITV works with the coolant. Next up I would check that the Rad cap is in good condition (check the rubber seal) then if all that fails move onto checking the thermostat by placing it in boiling water to see if it opens.

cstone

Hmm you could be onto something with the cap. I have never noticed that it was bad but will check tomorrow. I know there is a good chance that there are air bubbles in the system considering i just remembered i didnt bleed the system after tightening the FITV but i am pretty sure that the thermostat is stuck open because the temp isnt really an intermittent problem so much as it is when i am sitting it warms up but when i am moving it gets cold.

I will try to get around to replacing the thermostat this weekend along with cleaning the TB this weekend and will obviously at that time drain the coolant and bleed it at that time.

I will get back to you guys this weekend either way. One more question do you guys have a preference for a certain brand of thermostat?

cstone

wow lol i just realized how incoherent that last post was. i guess its time for bed. haha it is 1AM here now

YeuEmMaiMai

have you checked for vaccum leak?

if the car does not throw MASSIVE heat when moving, then yes most likely the t-stat is stuck open

cstone

i haven't sprayed the lines down yet but have visually inspected them (while waiting for my IACV to dry both times lol.) no cracks or anything. will spray the lines down sometime after installing the new thermostat that i just picked up today.

how would you guys recomed mixing the coolant? i know its in a ratio of 50/50 but am curious about how you guys go about mixing it? in a sepparate container?

Bwill9886

Make sure to check the TPS voltage as well. Its another one of the main culprits of this problem.

cstone

where is the easiest place to check TPS voltage at?

Shehzada

I had this issue a while back. I replaced my IACV and adjusted the FITV. No change.

It turned out my IM gasket was bad and creating a vacuum leak.

cstone

i think i may have read your thread about that. it may have been someone elses thread. how hard was it to replace? i'll spray some carb cleaner on there.

anyways, i dont know if i will have a chance to change my t-stat tomorrow. still going to try but not sure if i will have time.

GlassJAw

Check the TPS voltage at the ECM, you just need to find the right pinout for your car.
But seriously, try bleeding the cooling system first.
(mainly cos it's the easiest & cheapest possible cause to check)

Shehzada

http://www.cb7tuner.com/vbb/showthread.php?t=52454

I took a small spray bottle, filled it with water, and spray at all the vacuum lines while the car was running. As soon as I got to where the IM was, I heard the sound change. I tried it again and it did it again. That's how I confirmed it was a bad gasket.

As far as the difficulty, I had no choice but to take the IM out. I have an F22A1. Plus you have to clean and scrape off the old gasket.

Bwill9886

Yep, there or at right at the TPS which is located on the throttle body. Typically on left side.

You can find plenty of threads about exactly what to do.

cstone

so i replaced the thermostat today and now my heater works. i forgot to reset the ecu afterwords and have had a roaming idle a couple times. at this point i dont know if it is a vacuum leak or possibly still an air bubble in the system or just the ecu being a little confused. it was an improvement for sure. it only did it a couple times on the 10 mile drive home and when it did it corrected itself after a couple bounces. i ran the car for about 15-25 minutes with the radiator cap off and the fans never came on (the service manual says to let them turn on at least twice.) how long do you guys usually run your cars to belch the system? i gave up because half an hour seemed pretty crazy to me. maybe it was because it was under 30 degrees outside? idk...

on a side note i seemed to have fixed my abs while i was belching the coolant system. i heard the abs motor turning on right as i saw a spark from beside it and noticed a really loose ground bolt. tightened it up and it has worked fine the whole drive home. the light used to intermittently turn on and off.

all in all i am glad to have a heater and abs again but really want to fix this damn hunting idle once and for all. will do more trouble shooting this week when i have time again.

nus_dogg

Thats a weird idle for sure, but at least you got it to run better.

cstone

haha yeah i know. i have read tons of related threads and none sound like mine aside from the fact that it is a hunting idle.

LoneAutosport

Not to thread jack but my car on a cold start idles up to 2500 rpm and goes up and down for about 5 minutes what could possibly be my issue? After I let it warm up it idles perfectly fine.. Also how do you bleed the coolant? Any info would help...Thanks

cstone

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cstone

Sounds like your FITV is loose. heres a thread on how to tighten it. i would clean your TB and IACV while you are at it.

https://honda-tech.com/forums/honda-accord-1990-2002-2/cleaning-iacv-fitv-tb-1844067/

to bleed your coolant you just remove the radiator cap and loosen the bleeder screw (its on top of the t-stat housing which is between the throttle body and the valve cover.) let coolant out until it comes out in a solid stream with no bubbles. after that you should belch the system to make sure all the bubbles are out. for that just start the engine while its cold, turn the heater on full blast and remove the radiator cap. let the car run until the fans kick on twice. then shut off the engine and fill the radiator to the bottom of the filler neck if needed.

hope this helps

cstone

well it seems like the hunting idle has gone away now. i reset the ecu and it stopped again for a while then there were a couple instances where it bounced again but now it hasnt in about 2 days.

Shehzada

Good job on fixing your car. Feels good right? I'm been fixing my CB7 for the past 5 years.

cstone

thanks. i love to fix my own car, well maybe i should rephrase that... i love not to have to fix my car, but when something is wrong i love not having to take it in. come to think of it i have never taken any of my cars in to have anything done really other than brakes, tires, and alignment (i had an exhaust built for my truck too). so far i have dropped a tranny in a 91 prelude to replace the rear main (first big project), then replaced a drivers side half shaft on a 93 accord, a clutch job on an 87 dodge ram 50 (ghetto mini truck LOL), tuneups on all of my cars. i'm sure i am forgetting things but as you can see i do my own work. and yeah its a great feeling.

cstone

well its doing it again now. not nearly as bad. its only doing it when the engine gets warm and still not all the time. so now its time to spray all the vac. lines with carb cleaner and try to find a vac. leak. if thats not the problem, how likely do you think it is that my FITV needs replaced?

its been really cold lately (like 15 degrees and below) so i havent really cared much if my idle is bouncing. i'll post again when i get a chance to work on it.

xide_12

I know this is an old thread but did you ever fix it? Im having the exact same problem you have, and the only thing I havent checked yet is for a vac leak. Im hoping I dont have to replace the fitv or iacv