JDM H22A - fluctuating idle problem
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JDM H22A - fluctuating idle problem
ok, i have searched and searched all over the net and cant find anything that helps me. my problem is very strange. Ok, so here it is, replaced iacv on my JDM H22A. i still had the up and down idle. so i cleaned the fitv and tb. Screwed in the wax ball thing in he fitv as well. still no help. only check engine light codes i get are knock sensor and o2 sensor. now here is whats weird. if i adjust the tps one way it revs the car to a 3500rpm idle, if i adjust back the other way guess what? up and down idle again. there is no happy medium. and this is using 2 different tps with the same result. any ideas to get this figured out? Import Alliance is in 2 weeks and id like to get it fixed before then
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Re: bad idle problem
i did tighten the fitv but i didnt take it apart to clean it like that. i did however clean some of it but ill take it off again tomorrow and clean it like in that video. ill post back afterwards with results
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Re: bad idle problem
You'll need to set the TPS properly before diagnosing the problem. The TPS being off will create different symptoms and make it harder to figure out what's really wrong. The throttle plate needs to be in the correct closed position before setting the TPS. If the adjustment screw that dictates where the plate stops when closing has been messed with, that needs to be properly set first. Get a meter and turn the key to On without starting the engine. Check the resistance between the TPS ground wire and the battery negative post. Any resistance is a bad connection somewhere. If that wire's ok, stick the meter's black probe through the plastic sheath of the TPS ground wire, with the TPS connected, and leave it there. Use the red probe to pierce the TPS reference wire. There should be approximately 5v. Stick the red probe into the TPS signal (output) wire. With the throttle closed, there should be about .5v. Open the throttle manually. The voltage reading should rise smoothly to about 4.5v. Carefully set the TPS to .5v at closed throttle if it is off.
What exactly does it do during the up and down idle? Does the idle rev up to higher rpm's repeatedly or does the engine try to die over and over with the idle revving slightly to keep it alive? I'm going to guess it revs. If that's the case, you probably have a vacuum leak. A vacuum leak causes idle surging when the TPS signal reads closed throttle (~.5v) and steady high RPM when the TPS signal voltage is sufficiently raised.
What exactly does it do during the up and down idle? Does the idle rev up to higher rpm's repeatedly or does the engine try to die over and over with the idle revving slightly to keep it alive? I'm going to guess it revs. If that's the case, you probably have a vacuum leak. A vacuum leak causes idle surging when the TPS signal reads closed throttle (~.5v) and steady high RPM when the TPS signal voltage is sufficiently raised.
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Re: bad idle problem
Oh, and a "vacuum leak" can be as simple as the idle screw being too far open or the throttle plate screw preventing it from closing enough.
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Re: bad idle problem
I would think it's a vacuum leak also. Take the intake tube off and cover the throttle body with the palm of your hand while the car is running. If the motor shuts off. There is no vacuum leak. If it still running, there's a leak somewhere. Hope this help
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Re: JDM H22A - fluctuating idle problem
yes when the car bounces idel it goes from about 1500 to 2500. and i did the hand over TB and the car didnt shut off. it continued to surge. I know there is a leak somewhere but i cant find it anywhere. im going insane trying to figure this out lol. The only thing i can think of that would cause it to be so much of a leak is the intake manifold gasket. so im going to buy a new one tomorrow and put it on
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Re: JDM H22A - fluctuating idle problem
There are two schools of thought finding vacuum leaks. You can spray a light oil or spoon out some thicker oil onto the gasket or most other suspected leaks with the car running and it can temporarily plug small openings, causing a change in idle. You can also spray starting fluid onto a largish leak. This should cause the motor to rev. You can pinch closed vacuum lines or remove them and plug the opening to see if things like the brake booster, MAP sensor, etc. are leaking air.
#9
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Re: JDM H22A - fluctuating idle problem
might be a broken tb gasket! happened to me. man i did everything to find that sucker and did i feel stupid when i found out it was the gasket. also i've heard of ppl having clogged pcv valves causing the problem
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Re: JDM H22A - fluctuating idle problem
i bought some carb cleaner a lil while ago, im gonna try checking for leaks tomorrow. Im also going to the JY to get a knock sensor and o2 sensor plug. that should get rid of all my CELs i have right now. Im hoping i can find the problem soon cuz the idle is annoying sitting at redlights
#11
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Re: JDM H22A - fluctuating idle problem
i bought some carb cleaner a lil while ago, im gonna try checking for leaks tomorrow. Im also going to the JY to get a knock sensor and o2 sensor plug. that should get rid of all my CELs i have right now. Im hoping i can find the problem soon cuz the idle is annoying sitting at redlights
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Re: JDM H22A - fluctuating idle problem
turns out it is my intake manifold gasket leaking. sprayed carb cleaner around it and instantly it started to choke the motor down and tried to die. so new gasket is ordered and im hoping that fixes my problem
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Re: JDM H22A - fluctuating idle problem
yeah i know the o2 sensor can cause the idle to act weird but in my case a new o2 sensor did not work to fix the problem. But knowing the IM gasket is bad, now i will have the problem fixed as soon as it the gasket comes in
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Re: JDM H22A - fluctuating idle problem
im glad you found the problem bro, my ecu will be in by friday and i should be back by then to then its time to book it to TN sunday woot woot
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Re: JDM H22A - fluctuating idle problem
hey guys, thanks for all the help. Put the new IM gasket on today and the idle is perfect. Runs like a new car now
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