Idle fluctuation... pls help. - Honda Prelude Forum

N8_94SI · 08-03-2004, 02:51 PM

Anyone ever had a problem with their idle fluctuating from about 1000 RPM to around 2500 RPMS?? It happens constantly when I am stopped, whether in gear or not. It is very annoying... I've taken it to a mechanic who fixed it and said something about a vacuum tube, but it keeps coming back everytime I get it back.

To tell you the truth it has never really been fixed. But he returned my $$ so that wasn't a problem. Any ideas? Anyone ever experienced this??

-= Wasif =- · 08-03-2004, 02:55 PM

Idle control valve

red92si · 08-03-2004, 03:27 PM

could be a couple of problems... these have all been covered ad nauseum, but I will go over the basic list.

Possible Causes of Fluctuating Idle:

1. Air trapped in cooling system
FIX: with engine cool, remove radiator cap and allow to sit for 5-10 minutes. This will allow any trapped air bubbles to rise out. If problem persists, then repeat this a couple of times. If problem still persists then move on.

2. Dirty IACV Screen
FIX: remove the IACV and clean the screen with solvent, then reinstall IACV

3. Vacuum Leak
FIX: Check all vacuum hose connections

N8_94SI · 08-03-2004, 08:02 PM

nice... thanks a lot, I'll give those a try.

blueludeWV · 08-04-2004, 02:35 PM

I fixed mine by adjusting the TPS. It was out of wack from where I removed it when I did my swap.

ludevtec · 08-04-2004, 10:57 PM

Quote:

Originally Posted by blueludeWV

I fixed mine by adjusting the TPS. It was out of wack from where I removed it when I did my swap.

Really? I never even thought of that because I just changed my tps and cant figure out whjy my idle jumps like crazy!...hmmm

blueludeWV · 08-05-2004, 01:59 PM

I think that should be faq'd. Numerous people have had the dreaded idle surge after doing swaps. I did, twice! I adjusted the TPS to the specs in the Helms and then readjusted the idle according to the Helms and it fixed it. Actually, that would be the first thing I would check and then the other obvious places noted above.

Keith

toofastprelude · 08-06-2004, 08:45 AM

how do you adjust the tps? i thought it just plugged in and that was it?

blueludeWV · 08-06-2004, 11:25 AM

No, the TPS has slotted holes. If you loosen the two torx mounting screws you can twist the TPS and adjust the voltage reading.

toofastprelude · 08-10-2004, 08:02 AM

where does it need to be adjusted at? i have never heard of this before. anyone know what the correct readings should be?

N8_94SI · 08-10-2004, 10:54 AM

^^^ what he said...

Quote:

2. Dirty IACV Screen

Also where and what is this?

preludatic · 08-10-2004, 03:14 PM

did u do a search on this yet? numerous topics....

blueludeWV · 08-10-2004, 05:53 PM

I don't have my Helms here, but I believe its supposed to read .5 volts when the butterfly is closed and 4.5 when open. You might want to check that for accuracy though.
If you've ever removed or loosened the TPS, odds are its out of adjustment.

h8trix · 08-11-2004, 05:54 AM

:sigh: There is just a post on this and I said it should be FAQed... oh wells : \

Si_g · 08-11-2004, 03:21 PM

yo nate where u been hidin ? still got the lude i see, i told u i could fix that for you, its easy just let me kno, anyways, pm 'ed u.

blueludeWV · 08-11-2004, 10:33 PM

yo Si_g where u been hidin ? i thought u were gonna sell me that dash lens!

Si_g · 08-11-2004, 11:16 PM

^^^ damn man, my bad, i forgot, i just got caught up with finals and stuff. I m gonna find out shipping 2morrow from the post office, so pm me to remind me if i forget. I have to figure out how to wrap it so i can find out how much its gonna cost. : )

shadowz · 08-12-2004, 03:59 AM

You cannot adjust a Throttle position sensor, you can replace it,

red92si · 08-12-2004, 10:34 AM

Quote:

Originally Posted by N8_94SI

^^^ what he said...

Also where and what is this?

How To: Clean IAC Valve (smoothes out rough idle)

blueludeWV · 08-13-2004, 11:19 PM

Quote:

Originally Posted by shadowz

You cannot adjust a Throttle position sensor, you can replace it,

BS!!! Then how did I adjust mine?!? Did I imagine adjusting it?!? I don't think so! Does the Helms manual have the adjustment process in there just to f*ck with everyone?!?! I don't think so either!!!

Look... I think the TPS adjustment is the culprit for the f*ed up idle that most all of us have after an engine swap. I know because I've tried it all. And I mean everything!! Cleaning the IAC is also a very good idea. I did that as well. If you haven't ever touched the TPS then your problem probably lies elsewhere, like maybe the IAC. But, if you have ever removed the TPS, then I highly suggest checking and adjusting.

I'm in the process of moving and going to be offline for a few days but, when I'm back on, if no one has done a write up, I'll try to scan the Helms and do one. L8r.

Keith