My '95 Accord EX (4cyl VTEC) has bouncing idle. I have cleaned the IACV and the FITV. I did a test on the FITV by heating the end with a lighter and watched the plunger move. Looked ok to me so I reinstalled it. The antifreeze level is full and the hoses leading to the FIT valve don't appear to be plugged. If the idle isn't bouncing, it is too high...about 2,500 rpm. Even when the engine is at operating temp. I still have suction from the lower port in the throttle body. Should I just get a new FIT valve to see it that solves the problems?

 

When you reinstalled the FITV valve, did you tighten the valve until it was snug?

I would reset the ECU by pulling the 7.5 amp backup/radio fuse in the engine bay fuse box for a minute. Replace the fuse, then start the car. Allow it to idle until the fans come on. This should let the engine computer relearn the idle.

If you still have the idle problem, remove the snorkel from the throttle body. Clean the throttle body and the throttle plate (both sides). Then start the car. Inside the throttle body there are two holes. Cover the lower one with your finger. If the idle goes to normal (750 rpm), then replace the FITV. There are some coolant lines on the FITV that can get clogged up that you may want to clean.

 

As part of the cleaning of the FITV, I unscrewed the white plug on the end. After everything was clean, I screwed it back in all the way then backed it off between 1/8 and 1/4 turn. I had read something on-line about that. Is that correct? After I reinstalled everything, I disconnected the battery cables, thinking that would make the computer reset itself.

I have already cleaned the throttle body and the plate but I will check the back side of the plate to make sure it is clean.

Next I will try your idea of pulling the fuse then restarting the car to see if the computer will relearn the idle. I will let you know how it goes. Thanks.

 

After pulling the fuse, waiting, then reinstalling it and then getting the engine up to operating temperature, the lower port is still sucking air in. The idle was still bouncing between 1,000 & 1,500. I tapped the throttle so the tac went to 2,500 and now the idle is basically staying at 2,500. If I take the tac up to 3,000 it will gradually come back down to about 2,500, but no lower.

I then plugged the lower port in the throttle body with my finger and it only lowered the tac slightly. I then plugged the upper port and the idle came down to about 2,000, but went right back up once I quit plugging it with my finger.

What do you think? Try a new FIT valve? If so, is buying one on-line okay, or are those typically used ones that may have the same problem? Thanks for your help.

 

You must have a leak on your intake or the throttle plate is getting stuck. Covering that top port should cause the engine to stall out due to lack of air.

That lower port at operating temperature should have a slight suction on it. If plugging the lower port didn't change the idle, then it has to be something other than the FITV.

Search 9CPqbaSgcok on YouTube. That is a video on how to locate vacuum leaks.

 

how is a diagram for all the vacuum routes

 

You can also use some carb cleaner to find vac leak or bring the car to a shop that has a smoke machine and have them do a smoke test, usually only takes a few minutes to find the vac leak/s.

 

usually costs around 60 for the smoke test fyi

 

I had time this weekend to revisit my idle from hell issue on the '95 Accord. I finally narrowed it down to the two cables. I have learned that the one closest to the front of the car is the throttle cable and the one towards the firewall has to do with the cruise control. What I happened to notice is if I pushed to the right on the top part of the throttle pulley the idle would go down to where it was supposed to be. It didn't move much...wasn't even really noticable, but giving it a little boost made all the difference. So, I super cleaned (again) the outside and inside of the throttle body, concentrating on the two connection points inside where the butterfly is attached...using carb cleaner and a tooth brush. Still had the same problem of the idle staying high after I hit the accelerator! It looked like the cable for the cruise was completely tight and I thought that it may not be allowing the throttle to close completely. I backed the nuts off further up the cable line to loosen it a little. After three guesses, I got it right! Working great now. Thanks.