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Engine idles high while coasting in neutral

 
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Old 10-14-2008, 04:35 PM
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Engine idles high while coasting in neutral

Hi,

i'm having an issue with the idle...here's the rundown on it:

96 prelude S 2.2 manual trans

First started by idling low at stop...almost to 0.
Cleaned battery cable (was pretty corroded), changed fuel filter, air cleaner, sprayed out throttle body and sensor w/ B12 and still did it.

Adjusted idle manually so it idles ok at stop but now when i'm coasting in neutral the idle is around 1200. When i come to a complete stop it goes down to about 800.

Feel like the manual adjusting of the idle masked the real problem. Read that the speed sensor could cause that but speedo and trip tic is working ok (they said those would not be working if that was the problem).

This is driving me nuts. Anybody have an idea? Thanks a lot.
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Old 10-14-2008, 06:04 PM
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Re: Engine idles high while coasting in neutral

Try cleaning your Idle Air Control Valve with some carb cleaner, that fixed it for me.
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Old 10-15-2008, 09:01 AM
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Re: Engine idles high while coasting in neutral

Thanks...that had been done and it didn't make a difference unfortunately. Do you know if the part really goes 'bad' or if it needs to be taken off to be cleaned? It was just sprayed down in the throttle body, not removed.
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Old 10-15-2008, 09:38 AM
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Re: Engine idles high while coasting in neutral

Must remove it and then shoot it with the carb spray(Find this DIY in the resource thread). Try that and report back. I would also look at your spark plugs/wires to see if they are snug and proper spec. I had the same type of problem on my old 90 Accord f22a1(same engine as you).

edit: also top off coolant.
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Old 10-15-2008, 10:15 AM
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Re: Engine idles high while coasting in neutral

Thank you...i forgot to say that i had changed the plugs. Were you having the same problem while coasting also or just the rough idle? Had you adjusted the idle or just cleaned it out and then it was fine?
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Old 10-15-2008, 04:24 PM
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Re: Engine idles high while coasting in neutral

hey man wts up,,, i have the same problem mine turned out to be a faulty tps that i am still waiting for.. i had to order it online... try testing it see if its that
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Old 10-16-2008, 02:21 AM
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Re: Engine idles high while coasting in neutral

Yeah man, you have to actually take the IACV off, not that bad of a job. Just spray a butt ton of carb/tb cleaner inside of it, let it soak, spray some more, soak, until you run out of carb cleaner.
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Old 10-16-2008, 02:37 AM
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Re: Engine idles high while coasting in neutral

Quote:
Originally Posted by iguanamom View Post
Thank you...i forgot to say that i had changed the plugs. Were you having the same problem while coasting also or just the rough idle? Had you adjusted the idle or just cleaned it out and then it was fine?
When i stopped at a redlight, the idle would jump up and then down to almost to the point where the car was about to shut off...i never had to adjust my idle screw in my Accord, just had to clean out the IACV, which was full of carbon and coolant couldn't flow correctly in and out of the unit, which then reports to the ECU, which causes the frustrating idle problem.


Edit:
-also, if the TPS(throttle position sensor) is bad, you would be throwing a CEL -check engine light. A dirty IACV does not trip a CEL.

Quote:
Originally Posted by dbd6604 View Post
Yeah man, you have to actually take the IACV off, not that bad of a job. Just spray a butt ton of carb/tb cleaner inside of it, let it soak, spray some more, soak, until you run out of carb cleaner.
Right, but no need to use the entire bottle! just enough until you dont see carbon flow out. When you keep spraying and see clear fluid come out, then the IACV is clean.

For the people who didn't search or look at the resource guide threads, here is how to CLEAN YOUR IACV:
http://preludezone.com/showpost.php?...6&postcount=15
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Last edited by Prelude13; 10-16-2008 at 02:43 AM.
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Old 10-21-2008, 02:38 PM
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Re: Engine idles high while coasting in neutral

so did u fix it?
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