jdm d15b engine.. when i start it it idles good. once the car is warm eventually it will idle from 500-1200 over and over and over.

brand new IACV. checked fitv and cleaned and works. i have found no vacuum leaks. bleed the coolant system.

i donno what else to do.

ill note that when its idles weird like that, when i turn my lights on, or turn the heat control to max the bouncing idle will stop.. any ideas why?

 

check the lines but also recheck that IAVC

 

Do you have a stock or chipped ecu?

 

the iacv works fine. i even tested it. its new. ecu is stock p28.

 

Stock ECU is not a P28, dude.

 

I said im using a stock p28.... as in, "not chipped"

 

does it idle like its revving up for a second then dies down, then revvs up again?

cuz my d16a6 does that after it idles for a few minutes. it starts to revv up and die down. it doesnt stop until i turn off the car.

 

i have the same problem on my ls...still havent found any solution tho =[ it'll even stall sometimes

 

Yup, that is exactly what it does.

when I first start the car up, it idles higher then normal, but hats normal because its cold outside. after a few minutes it will idle down. and it will idle just fine. but as soon as i rev it up a little and let off the gas it willl drop down to 500 then bounce up to about 1200, then back to 500 then to 1200 over and over and over. it wont stop.

but as soon as i put a load on the engine. (turns lights on, or turn the heater on) it will idle normal again. I have no idea whats wrong. its starting to really bother me

 

wow i thought it was only me who had this problem.
im excited to see what the resolution to this problem will be.
keep this bitch updated lol

 

a jdm d15b is the 3 stage vtec motor. a p28 isnt the right ecu. it should be a p08.

 

ha your wrong man. theres a few different JDM d15b engines. some are non vtecs, some are vtec and there are also some that are 3 stage vtecs. I have vtec. i have confirmed this. and the p28 works fine with this engine. It does make my motor run a little more rich then normal, but i plan on getting it chipped soon anyway.

 

i have a stock 90 CRX Si d16a6 with issues that are just about the same.

i've had the car for about 5 years, and it's been sitting for about 2 years. now i'm fixing the axle issue and it's going to be my daily driver again. anyways..

when i start it up it revs up to about 2.5k, then down to 1.5k, then back up to 2.5k..
so i read about how to take apart and clean the IACV. so i did that today, and now it starts up and idles at about 1k then up to 2k, then back down to 1k.

so i found a post by: wildoutwhitegsr https://honda-tech.com/forums/acura-integra-6/%2A%2A%2Ahow-clean%2A%2A%2A-your-iacv-k-idle-air-control-valve-1575913/ and went to town.

so when i had the IACV apart and cleaned it, there didn't seem to have too much junk in there, but also i'm not sure what it is meant to look like. there is an allen wrench adjustment fitting that i didn't mess with, but i'm not sure if i should have.

i just got the car back from the guy who i had install the new axles and he didn't know **** about the intake problems

i guess i need a way to test the IACV, or at least someway to know if its working or not. also find out what else effects the idle.

any help would be nice, thx in advance

 

fair enough. i shouldnt have assumed. ive been researching the 3 stage a bit and forgot the 88-91 and 92-95 motors.

 

yea thats weird sounds dead on for symptoms of a dirty iacv. have you checked the TPS?

neophish, only way i can think of how to test the iacv is install your iacv in a homies car with the same engine, or at least a similar engine which uses the same iacv, and see if you can reproduce the problem in their car.

 

i bought a brand new iacv. $130 and i still have the bouncying idle. once the car is warm it will start doing. only when warm. but whats weird is... when my lights are on, or my heat is on full.. it wont do it. im so confused..

 

Update: at cold startup, still surging from 1.5k to 2k. but once its warmed up, it seems to be fine. so at least it does go away once its warm

 

if your idle surges at start up... thats most likely your FITV. Thats whats controls your idle when the engine is cold. after its warm the iacv takes over.

 

bleed coolant again?

 

sure did.

 

How about the battery, I fought with a bouncy idle for a month it would jump from 1000 to 500. I tried all of the above finally I put a charger on the battery and it the voltmeter was bouncing just like my ilde. I charged it over night and now its perfect.

 

i bought a brand new battery for it but it still bounces...its annoying when it starts doing that. i have to give it just a tad bit of gas to keep it from revvin