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Z

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I have a d16y8, I'm running hondata on a P28 ecu. I'm having some major idle issues. When I start the car it idles around 2500rpms until it warms up. Then after that it still idles high, around 1200rpms. When I come to a stop sign, or a light, the idle bounces between 1k rpms and 2k rpms. Sometimes it bounces and sometimes it's just high. OK, I've done some research and some say it's the iacv. Well I though it was too, but I changed this out about 6 months ago, so it's pretty new. So I'm pretty sure that's not it. It's obd1 but running an obd2 iacv. It's a M/T y8, so I was told it's already a 2-wire, so I don't need to convert it. I've had this issue for awhile, that's why I got the new iacv. It fixed it for a little bit, but it gradually got worse over time and now it's the worst it's ever been. Another thing I can think of that I don't know if it has anything to do with it, is I have a test pipe so the O2 sensor that went in the cat is just zip tied out of the way. I doubt that has anything to do with it. Please help me out with this, it's really pissing me off. I was also told it could be the tps, but if it was that, wouldn't it happen all the time?
 
Z

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The iacv was brand new. Also the tb gasket and intake mani gasket were put on when I put the turbo kit on.
 

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I
95 Civic coupe
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i have a very similar problem, and i'm using crome. others running uber have the problem too. i think the problem lies elsewhere (not iacv). maybe grear correction or just using the obd1 ecu with a y8. not sure
 
Z

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Damn, anyone else having issures or know what's up? When I got hondata and got it tuned it idled kinda high, like 1k. But it wasn't surging.
 

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I've got a 97 civic ex that does the same. I did some research and found that people using the newer uber and crome have this idle issue. Im going to try an older version of crome or uber and see if that works.
 

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i save your ass when you wreck
94 hatchback cx
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i have this problem to. my idle bounces up and down and wont stop. its alright when im moving just at an idle its fucked up. only thing is my car is stock other then intake header and exhaust...no hondata, uberdata or chrome
 

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the MAD scientist
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Yeah, I've been having simmilar issues. It only happens when its cold. It's normal unless I blip the gas, then revs start going up and down. When the revs go down the WB reads dead lean.

No vacuum leaks. When I get home from work I'm going to try and adjust the IAC duty cycle slider thingy in Crome and see if that helps.
 

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d-series smartass
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i forget the name of the valve, but this is what worked for me:

under the tb towards the firewall is a metal plate with two screws on it. take the two screws out, and inside is a white plastic ball insided a plastic ring. use a small screwdriver to turn the ring in clockwise, maybe a 1/2 a turn (usually). this fixed my problem after months of headaches. try it out, it will work.
 

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d-series smartass
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try this link

and this one

here's what a helpful post said:

Yup, had the same problem not too long ago. You'll need to remove the FITV, 4 bolts if im not mistaken. Some coolant is going to piss out after you disconnect the hoses but just let it drip.


There are two different metal caps, both held by 2 screws on opposites ends of the FITV. Remove the larger housing one first (not the flat metal one) and hold a lighter underneath the wax carrier (little metal thing inside that housing) while looking into the hole on the FITV body where it connects to the TB. Ensure that the piston IS moving after heated up, it may take a few seconds of holding the lighter underneath it.

If it moves, you're in luck, you can fix it yourself (even though Honda specifies these are set from the factory and theres no "fix" for them), and if it doesnt move, you'll need a new FITV.

If the piston moves, then re-attach the metal housing with 2 screws and remove the flat metal cover from the opposite end. There will be a small white plastic screw-in holder that limits the piston travel (i.e. this determines how much extra air the FITV is allowed to inhale to increase idle speed at cold idle).

All you need to do is adjust this, in my case, the holder had come completely loose and was not limiting travel whatsoever. Just tighten the holder down until it is snug (I was able to do it with one screwdriver, you might have to use 2 though being that it has a hole in the middle and two notches on the sides to adjust it).

Re-intstall the FITV to the TB and you're set...I'd suggest starting the engine with an open TB (intake not connected) so that you can check that everything is working properly. Sorry this turned into such a long post, just trying to be descriptive as I don't have any pictures to post. Good luck
 
Z

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Discussion Starter #15
Yeah that's all fine and dandy, but I don't have a FITV
 

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These symptoms are similar to having a uncalibrated TPS (like I did the other day, and still am trying to completely 'dial out'). However, since I'm sure ya'll didn't do anything with your TPS...

The issue may be coming from something similar - which is poor timing/fuel delivery maps at idle. When the TPS is uncalibrated for example, the ECU will inject fuel at erratic rates and cause the idle to bounce a little - sometimes even a lot. ESPECIALLY once the throttle is 'blipped'.

Just a thought - you may need to recheck your tune at idle.

Nathan
 

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I have a similar issue, but it I've tried every solution presented and it seems to work for a couple of days, then goes right back to the way it was before. Maybe if I set it to idle high, it won't kill the engine at stoplights.
 
Z

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Discussion Starter #18
Finally figured it out. It was a vac leak but it wasn't a line, it was leaking out og=f the evap purge solenoid. I just disconnected the evap system and it purrs like a kitten now.
 
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