Bouncing idle issue once warmed up...

Lankysod07 · Post by **Lankysod07** » Mon Feb 29, 2016 3:28 pm

So the car was running sweet all weekend with no issues.

Then this morning, I wake up start the car to warm up before my trip to work as normal.

Once the car has warmed up the revs seems to sit at 1200rpm, until i touch the throttle. As soon as i tap it once, the revs start bouncing between 900rpm and 1400rpm.

I toke it for a short drive thinking it might just of been a singal time event but nah, stopped at traffic lights still the same.

I havent changed anything on the car over the weekend apart from the bodykit, I topped up the oil maybe mid week last week, a very small amount.

Any ideas? My Idle control valve needing a clean or something?

Cheers in advance. Brandon

Post by **Merlin** » Mon Feb 29, 2016 3:40 pm

Lankysod07 wrote:My Idle control valve needing a clean or something?

Yar this, if it still is not fixed check the FITV and bleed the coolant.

Post by **clarelude23** » Mon Feb 29, 2016 3:55 pm

^^ya. I had a similar problem. Purged the coolant and it was fine.

Lankysod07 · Post by **Lankysod07** » Mon Feb 29, 2016 10:15 pm

Hmm, cleaned the idle control value, wasn't too bad. Didn't resolve

bled the coolant as that's the only thing I've touched all weekend, I open the rad cap and had a little look. Since then it's started this hunting issue. Again tho bleeding the system didn't do anything. What does The FITV do?

Post by **NafemanNathan** » Mon Feb 29, 2016 10:27 pm

The Fitv (fast idle thermal valve) allows more air to by pass the throttle body on cold start up. They can quite often be problematic and cause the issue your having.

Start the car and allow it to warm up and start hunting. Then remove the induction pipe right up to your throttle body. Whilst the engine is still running and hunting block the lower large hole in the mouth of the throttle body with your thumb.

Hopefully the revs should drop and the car should idle fine. If this works it's because you are preventing the extra air from bypassing the throttle body. The engine no longer requires it because it's up to temperature, but a dodgy FITV will play silly buggers with your idle.

Your options are to either tinker with the FITV as sometimes they can self adjust, but the likelihood is it will need replacing.

If covering the hole does jack all its not the FITV at fault.

YouTube · Post by **Sailor** » Mon Feb 29, 2016 11:20 pm

Our Civic did this.
It cured itself after a week, so I was none the wiser ...

'92 Si VTEC · Post by **jjmartin349571** » Mon Feb 29, 2016 11:28 pm

My pearl grey BB4 is doing this currently - I unclipped the IACV connector and the bouncing stopped so I'm assuming it needs cleaning. Haven't done that yet as Laura is driving the pearl grey lude currently...

Lankysod07 · Post by **Lankysod07** » Tue Mar 01, 2016 10:28 am

NafemanNathan wrote:The Fitv (fast idle thermal valve) allows more air to by pass the throttle body on cold start up. They can quite often be problematic and cause the issue your having.

Start the car and allow it to warm up and start hunting. Then remove the induction pipe right up to your throttle body. Whilst the engine is still running and hunting block the lower large hole in the mouth of the throttle body with your thumb.

Hopefully the revs should drop and the car should idle fine. If this works it's because you are preventing the extra air from bypassing the throttle body. The engine no longer requires it because it's up to temperature, but a dodgy FITV will play silly buggers with your idle.

Your options are to either tinker with the FITV as sometimes they can self adjust, but the likelihood is it will need replacing.

If covering the hole does jack all its not the FITV at fault.

Ill try this on my lunch today and see if it drops the idle, is the car ok to drive at the moment as its my daily?

Also anyone have a spare FITV I could buy? Ill post up a new topic abit later.

Cheers guys, brandon

Post by **Merlin** » Tue Mar 01, 2016 10:41 am

Yeah it is fine to drive. Have a go at adjusting the FITV before you buy another one. Giving the plunger a tighten may solve the issue.

Post by **vanzep** » Tue Mar 01, 2016 11:21 am

Ive cleaned the fitv before and you just unscrew the plunger - give everything a good clean with carb cleaner screw the plunger back in right the way to the bottom then back it off a quarter to half turn and then refit it

If this doesnt fix it then maybe look at the alternator
Im not 100 percent sure but idle issues can possibly be linked to alternator on its way out. Check the bearings on the alternator arent making any nasty noises etc ....