High idle speed problems ( possible causes )

[Jobi Joba]

got two separates problems on my R:
car warm or hot: nevermind, the engine iddles gently between 900 and 1100 rpm which I think is fine for a highly modified engine.

first problem:
engine hot, I blimp the throttle or I release the throttle pedal, on neutral while decelerating or braking and before the engine rev is lower than 1600rpm. Then the revs falls to approx 600rpm, the engine hesitates A LOT, is closed to stall, afr reads approx 10:1, and finally after a few seconds (5 to 10),the revs goe back to 1,000rpm and the afr becomes normal again.
Possibly due to mechanical adjustment?

second problem:
engine hot, I floor the throttle, rev up to approx 8k rpm, shift gear, floor it again, etc... In other words, I use my R as it should be. When the engine comes back to iddle, it can't get any lower than 1,500rpm or so. Nevermind what I do,it can't get any lower. The only thing to get things back to normal is to open the hood and back off the throttle actuator manually of just a very little bit. It seems it doesn't want to close completely by itself, like stucking open a little bit.
Can it be due to adjusting screws?

 

[hmmm]

Check the MAF connection.

Had this on a mate's car where it would nealry stall at times. Turned out to be the pins in the connector plug to the MAF had gone in a little.

 

[GTIR-LOZ]

is the manifold new/tinkered with the throttle stops maybe incorrectly setup also check the tps sensor voltage at idle

 

[Jobi Joba]

is the manifold new/tinkered with the throttle stops maybe incorrectly setup also check the tps sensor voltage at idle

TPS sensor voltage is above its normal value when I have the high iddle problem. So at least my TPS is fine and correctly set up.

Thinking about the stops too...will check soon.

 

[GTIR-LOZ]

another question about this idle malarky i disconnected the lambda sensor and saw no change in the revs, is this a good check to see if the lambda sensor is causing the idle prob or does the ecu raise the idle to compensate for no lambda signal

 

[GTIR-LOZ]

jobi i would say either your tps sensor is faulty or the throttle linkage is sticking open on mine the tps reads normal when i have high idle

 

[slammed_gtir]

mine idles at 1500rpm wether its hot or cold? is this most likly to be base idle adjustment screw?

 

[Braveheart]

In responce to antgtir issue regarding "Hesitation between 3k to 4.5k rpm + Fueling issues??" I had a similar problem.
I picked up a GTIR last month and felt it was running a bit funky. It seemed to pick up ok at low revs but stuttered and hesitated badly between 4.5 - 5k rpm. When I layed off the gas the damned thing wanted to go. Not good when you are entering a corner looking for engine breaking. It was also idling high (1100rpm) and just felt a bit unwell.
The car it's self is bulk standard except for a mongoose exhaust (without cat) and sump guard but with a poor service history (jap 18k service). I bought it off a farmer who had owned it for 4 years and done 2k miles in that time. It has 60k on the clock, it was imported in 2002.
Anyway, given the service history and poor performance, I booked it in for the full boona.
Falkland performace changed all the fluids, plugs, point, air filter (now K&N) front disks and pads and rear pads. (disks and pads were well shot.... it was grinding along)
I was full of hope but the car was still running poorly.
It turned out to be the knock sensor (error code 34) This sensor they explained was there to pick up pinking etc and when triggered would retard the ignition timming by 6deg. It's meant to reset it's self but did not and I thing I will source a new sensor.
They reset the ECU and the error was gone. The car is now running fine. Much smoother, pulls all the way through the rev band and thankfully enters engine breaking now when I gas off. I did refrain from taking it out on the track at knock hill last sunday however as I have a sneaky suspition the problem would return plus I did not want to buy another set of brake pads so soon.

Hope this information helps and I may post it in a couple of other places on this web site.

Lang may your lumb reek... all the best Braveheat (Scott)

 

[rx jamie]

mine had been idling high recently around the 2k-2.5k mark.i tried everything and couldnt fix it. eventually i just opened the bonnet while the car was running and made sure the butterflies where closing properly, by forcing the throttle closed with my fingers. couldnt believe the result. must have been dirt/oil under one of the butterflies as the throttle clicked back slightly and now the idle runs spot on.i have had no problem for two weeks. runs 8-900 now.

 

[djdoc360]

Do yuo know what the hole on the ECU does? I did play around with it and my idle did change.

 

[Fusion Ed]

Yes it affects idle co emissions.

 

[djdoc360]

oh ok. there have been times were my battery was very low and when i tryed to crank my car over, you could here the screw spinning. so i took the ECU with it still plugged in to see and it was moving it when i was trying to crank it.

 

[britishrallying]

Hi all,

Currently I have a prob with tick over! When I start up from cold it revs at 1500 then after a few minutes falls off to around 1000 - 1100 there abouts. but as soon as I touch the throttle slightly it idles at 1500 again. If I turn the ignition off then start it up, it goes to 1500rpm for a few seconds then back down to 1000 - 1100, again if i touch the throttle its back up again !

Checked my timing woth a gun this morning, and at idle without touching the throttle its slightly behind 20, only very slightly!! should this be adjusted for running 1.3bar :-0

Checked the idle air screw, was about a turn out, screwed all the way in and didnt change the idle, screwed it out and it did increase the idle, adjusted it to turn out.

I even put my stock dump valve back on to.

Im running 1.3bar with a front mount, walbro 255, hks filter, custom exhaust, apexi avc-r....

Any help appreciated

Thanks

gaz

 

[Booney]

mine wud idle at approx 1600 rpm and hold there on idle, so adjusted IAS screws too make it tick over at 1000rpm now.. but feels like its bogged right down npw on a run between 2000 - 4000

 

[ollydj]

Hi all, i spent months and alot of sleepless nights trying to cure mine. I tried everything on the list above when one day a wise man from gtir-us (BOB) said to clamp off the the breather pipe on the top left hand side of your rocker cover the goes to your throttle bodies. It apears that there is some kind of a valve in there that fails and allows air past it on idle, therefore increasing idle. You can always tell a good one from a bad one by sucking on them, you can feel the valve open and close as you suck on a good one. Go on give it a little sucky. Worked for me boys!

 

[PobodY]

That's the PCV - quite a few people just take it out. Steve sells the kits to blank it off.

 

[Fusion Ed]

Yep air is supposed to pass through this, but its for emissions purposes, and so can be blanked off if your not bothered about that kind of thing. Along with that you will often see a drop in idle speed as more often than not that pipe with other problems will cause a high rpm. But blanked off it 'cures' it.

 

[Tim]

Would a leaking exhaust manifold cause high idle speed?

 

[pulsarboby]

I tried everything on the list above when one day a wise man from gtir-us (BOB) told me to fook off

:lol::lol::lol:

Would a leaking exhaust manifold cause high idle speed?

possibly as it could be drawing air back into cylinders

 

[stifler1603]

since i installed my walbro pump my R idles at 1500rpm and is killing me in petrol should i install a fuel pressure regulator?