Wonky Idle

[mcfly]

I figured i would ask too see if anyone other then myself had to deal with a weird idle problem.

There are no leaks to be found
Reset the ecu

The car pulls great, for the power it is supposed to have.
For some reason the idle has not been right all winter. When i picked the car up it idled at 750/800, after two months of hard driving it randomly stalled and when started again the idle was magically at 1200-1700.

When the idle hits 1700 it bounces back down to 1000, it sometimes bounces, most of the time it is just high at 1400 or so.


Figured i would ask if anyone dealt with this before, prior to me having to get dirty. I will start swapping parts if it comes down to it.

[kelaog]

Is your Throttle position sensor working properly? I know when mine was disconnected it was messed up like that.

Also try adjusting it so it idles around that point. Should be .50v, but I'd get it closer to .49. Try measuring it to see what it says with the car in the on position.

Ps: I should mention that if yours is busted I have a spare throttle body including TPS for sale.

[judasentinel]

AACV - If the AACV is messed up (needs cleaning or the spring is broken inside), it would idle higher, as I learned from experience.

The other thing is what Andrew said - TPS setting can result in a rough idle, but then it also causes rough rev climb.

Since there are no leaks, I am inclined to think of mechanical things that cause the idle to change - AACV, TPS, sticky throttle cable/spring mechanism (the stuff that gets pulled on the throttle body's side when you press the accelerator) or CAS positioning that increases idle ignition timing and the resultant idle revs.

[kelaog]

AACV - If the AACV is messed up (needs cleaning or the spring is broken inside), it would idle higher, as I learned from experience.

The other thing is what Andrew said - TPS setting can result in a rough idle, but then it also causes rough rev climb.

Since there are no leaks, I am inclined to think of mechanical things that cause the idle to change - AACV, TPS, sticky throttle cable/spring mechanism (the stuff that gets pulled on the throttle body's side when you press the accelerator) or CAS positioning that increases idle ignition timing and the resultant idle revs.

Oh right, forgot about the timing :P. Try bumping the CAS around.

I found I didn't notice any problems with the revs climbing when my TPS wasn't plugged in, and improperly adjusted. It just idled like crap.

[Deus_Ex_Machina]

My car does exactly what mcfly's does to the tee
makes starting in first gear pretty damn easy lol

[BenC]

Mine was idling similar. It went up and down randomly (600-1500) and idled rather high most of the time. I tried testing for air leaks with the propane method but it did nothing.

When I was taking my motor apart I noticed the intake gasket was missing in a few spots. If your bored one day try putting new intake gaskets in. They are cheap and it's worth a shot

[mcfly]

Thanks for the ideas.

tps is .5v, that was the second thing i tired.
I will try swapping out the acc with another one i have kicking around

[Arch]

I had a intake gasket replaced and installed hks bovs, now mine idles all over the place aswell and pulls randomly. Im guessing they havent blocked the recirc to the bovs?

[derbeck]

Get rid of bov our cars hate them lol I've tried also check mafs mine caused a ton of problems

[Arch]

lol, yeah i called around and its just the recirc that needs to be blocked. Ill post back after I get my car back thursday afternoon

[Stuntmonkey]

Mine has a similar problem, only when it's cold she turns over and sputters like she is going to stall, and then catches idle up to about 1k rpm. Everything else is fine after then, power is ok, climbs smooth, with the exception of chugging hard in 2nd and 3rd from 3.5k.

[nelsonmxmarc]

Yea, this isn't from 2008 or anything..

Mine has a similar problem, only when it's cold she turns over and sputters like she is going to stall, and then catches idle up to about 1k rpm. Everything else is fine after then, power is ok, climbs smooth, with the exception of chugging hard in 2nd and 3rd from 3.5k.

IACV under the intake plenum is fudged. It's a swinggate assembly and over time it either seizes or the circuitry fails.

My opinion, just ditch it completely, and tap the throttle on startup to mimic the swinggate opening for that primary boost of air on start. Mines been like this for a year.

[Skym]

Most of the time it's because the start up tables on ECU are too rich and notice it happens after engine is modified.

Just crank engine for longer to get pistons pumping and then let go of key. Engine should start fairly normally. Also check for airleaks around throttlebody and IACV, AACV vacuum hoses.

[Stuntmonkey]

IACV valve eh? I will check that for sure.

I need to get some vacuum hose and replace all the little ones and ziptie them. I figured it was probably an inter cooler piping that has split, that would also explain my 3k rpm chugging.

[nelsonmxmarc]

That would be a boost leak then, so you're right, that would cause the chugging, but wouldn't necessarily affect start up or conditions under vacuum