Suggestions for idle fluctuation fix? - Honda Prelude Forum

aneurysm · 02-15-2005, 01:26 PM

Running a 95 Si with JDM H22A swap....

Shortly after doing the swap I am having idle fluctuation where it revs between 1000 and 2000 rpms.

What has already been done:

brand new idle air control valve
fast idle valve replaced
all vacuum lines checked and rechecked
coolant levels 100%
ECU has been reset

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please let me know if you have had similar problems and what you have done to fix it. the idle sometimes is steady (when it is started cold, and sometimes at a warm startup before you depress the accelerator).

Thanks in advance!

brad

Deepmist · 03-04-2005, 02:00 AM

Just got my car back from shop with exact same swap and I ran into the problem tonight drivin to work in the rain with headlights and defroster on. If they can fix it i'll ask them what they did. Did you happen to find a solution between your last post and now? There is no way I can let this go, my exhaust is pretty loud and when i'm at a light it sounds like i'm reving my engine over and over.

jsmooney · 03-04-2005, 07:00 AM

hmmm, i gave up on mine, but PLEASE tell me if you get it fixed. good luck. i have tried numerous things, im about to say "fvck it" like i have for the past six month

rayslude · 03-04-2005, 09:40 AM

3 things could be the problem, first of all you may have air in your coolant lines, second your IAC might need to be put back into cycle, third of all your tps might need to be adjusted. do a search and you can find a fix for all 3 of these things.

aneurysm · 03-04-2005, 11:31 AM

Quote:

Originally Posted by rayslude

3 things could be the problem, first of all you may have air in your coolant lines, second your IAC might need to be put back into cycle, third of all your tps might need to be adjusted. do a search and you can find a fix for all 3 of these things.

I already stated that coolant levels were 100%, and a NEW IAC has been installed.

I finally figured out wow to test the IAC. Its in the Helms book. You use a meter to measure the TPS sensor on the WHT/TEL wire, ground lead goes to chassis ground. This wire (WITH THE IGNITION ON) should ready 0.450 DC volts at resting throttle position. As you turn the throttle with your hand the voltage should gradually increase from 0.450 --> 5.000 volts. As maximum throttle (WOT) wit should be 5.000 volts.

Adjusting the TPS is possible, but a pain in the ass. You must remove the throttle body, and drill out the rivits which secure the TPS to the throttle body. Once you drill the heads of the rivits off you can use needle nose pliers to back out the old machine threaded bolts.
Once you have those out, replace them with new machine threaded bolts that yo u can adjust while the throttle body is back in place.
With new machine thread bolts in place you will see how there is about 1mm of turning ability of the TPS against the throttle, you can plug everything back in, and turn the TPS with the screws loosened until the voltage reads correctly.
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Mine ended up being toast (voltage was 5.000 permanently), so I've ordered one from Ebay for $25. Don't try to call Honda or Acura for one because they only come on a NEW throttle body (about $500), they are not sold by themselves.
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Hope this helps some of you out. I'm pretty good at idle problems by now, so please let me know if you are having other unknown/unsolved issues.

Brad

preludatic · 03-05-2005, 12:26 PM

hey how do you put your IAC back into cycle???

Deepmist · 03-13-2005, 09:00 AM

I called the shop that did my swap, they said to warm up my car after letting it completley cool. If it still did it the IAC valve needed to be replaced, if not they probably missed a vaccuum line. I did it and it fluctuated without driving the car at all from a cold start after it warmed up. I brought it in to replace the valve but when I got there he decided to have me start it up, he played with the idle settings for about 20 minutes goin up and down till he found a place right between stalling and fluctuation. I would push the brake in and let it out while he did this to try and make it fluctuate or stall if the revs were too low or too high until it did neither. Car runs perfectly now.

preludatic · 03-13-2005, 10:07 AM

Yesterday i fixed my idle problem after 4months acting retarded its soo nice its liek haing a new car. I found someone who did a great write up on it and followed what they had said and it worked great, it happened to be the FITV was loose, the person who did the write up said that they are a common problem in all hondas. Its right under the TPS sensor its got two 8mm bolts that hold a plate on, than you'll need a mirror to see what you are doing its one the back side of the Intake manifold. I pushed in on the valve, its like a round knob. The idle dropped and stabilized after pushing on it. so i knew that was the problem. theres a white ring on the outside of the knob, its hard to turn and hurts your fingers, btu i got it down and now my lude runs perfect.

Grant · 03-14-2005, 05:26 PM

I would go with a vacuum line issue..

aneurysm · 03-14-2005, 06:27 PM

Quote:

Originally Posted by preludatic

Yesterday i fixed my idle problem after 4months acting retarded its soo nice its liek haing a new car. I found someone who did a great write up on it and followed what they had said and it worked great, it happened to be the FITV was loose, the person who did the write up said that they are a common problem in all hondas. Its right under the TPS sensor its got two 8mm bolts that hold a plate on, than you'll need a mirror to see what you are doing its one the back side of the Intake manifold. I pushed in on the valve, its like a round knob. The idle dropped and stabilized after pushing on it. so i knew that was the problem. theres a white ring on the outside of the knob, its hard to turn and hurts your fingers, btu i got it down and now my lude runs perfect.

what is the FITV?