AC/Idle Problem

[sLADe781]

Originally Posted by Igovert500

So, if you don't turn the AC on at all, it holds a steady warm idle at ~700?

Unfortunately not. If that was the case then I'd just keep my AC off as I hardly use it anyways.

I was wondering.....when people mention testing for boost leaks, is that only for GTs with turbo engines or can N/As have boost leakst too? I mean....do you pressure test an N/A engine? Because I always thought that was for turbos only when people talked about boost leaks...

[Musashi3000GT]

That same crap happend to me a few years ago. I messed with the IAC and cleaned the throttle body, resset the computer a zillion times! nothing worked. I took it to the dealer and they did a reflash on the ECU, set me back 350 bucks but never bothered me again. oh and they didnt replace anything on the car, just reflash.

[sLADe781]

Reflash? The hell is that??? And damn bro, where ya been? LOL Too busy on the GTO forum that you can't come back over here??? Just giving you a hard time man....but seriously, what's a reflash? And would you happen to know the boost leak questions I asked?

[Musashi3000GT]

Our cars cant boost leak but yes they can have compression leaks and if the head gasket, intake manifold gasket, header gasket is worn then it will leak air, HOWEVER, those types of air leak will not cause the trouble you are having.
The reflash is to wipe the ECU clean and set it back to total zero. in other words it like reformatting a computer. Since the ECU tends to learn certain parrameters its not uncommon for it to learn a bad parrameter and then not override it, as a ressult comflicting codes will cause these little headaches.
Apparently just pulling the battery terminals or pulling the ecu out wont completely reset the computer on these cars.
Mitsubishi has a comp. they plug into the diagnistic port and reflashes everything, gets rid of all the codes and set the parameters back to stock.
My symptoms where a bit more extreme then yours though, It started out just like your car but then it simply would not hold idle. If you stopped at a red light it would drop all the way and die. I had to hold the revs manually with my right foot on the gas and brake with the left foot.
Good thing my dad is an ex rally driver and taught me left-foot-brake techniques
I almost crashed it a few times but i got the hang of it.

I cant go to the GTO forums! they hate the new GTOs, all they care about are the 70s models.....bastards!

so yeah I come around here once in a while.

[sLADe781]

Ah I see. But damn, $350??? I need to rule out every other possibility before I go and get that done. Any other ideas? I'm beginning to hate my damn car man....wtf is the point of having it if you can't even drive it???

[Musashi3000GT]

your just pissed cause you cant fix it!

What do you expect from high maintenance Japanese sports cars of the 90's?

I say do rule out every other possibility but you jumped the gun on getting that new IAC, should of cleaned it first man. I hope you dont have to take it to the dealer though. I dont trust them but in my case I was dessperate.

[sLADe781]

UPDATE: Here's something weird...my car began to hold idle today after I fumbled around with it a bit more. I took off the new IAC I got to check the resistance between the coils to make sure they were good. After that, my car eventually just started to hold at a low idle after having it on for a bit--around 500-550. So I turned the BISS to about 800 and that's where it stands now so I'm thinking that it might be okay. I do have a couple questions though:

1-is it normal to have to adjust the BISS after you install a new IAC to get your idle back to where it's supposed to be? I mean, if the IAC was the same then I don't understand why the BISS would need be adjusted?

2-I don't understand why after I put in the new one my idle was still so sporadic? I must admit that my car didn't die this time but the idle was still very sporadic. I know it takes some time for the ECU to relearn everything but I had my car on for at least 30 minutes and it was still idling crazingly.

3-after I turned the BISS, whenever I gassed my car it seemed as if I would have more power in the pedal now. Umm...is that normal? Is my gas mileage going to suffer because of that?

Well, I'll be driving to work this coming week so I'll let you guys know how it goes. And of course if I'm having problems again then I'll be back. Thanks to all who helpped with this problem. I really appreciate it so much...and a special thanks to Stealthee as I am constantly picking at his brain through AIM. Thanks bro.

[Linebckr49]

i've never heard of flashing the ECU. sounds like it should work. not that it will solve your problem, but it seems there's a high probability that it would. i guess if you replace a bunch of parts, you could have the ECU flashed as a last-ditch-effort.

anyways, i would just call around to different dealerships and ask them how much it would be to flash your ECU. i bet differen't dealerships charge differently. i know that when i buy parts from mitsu, they are never the same prices at different dealerships.

so that would be your best bet, now that Musashi has enlightened all of us, as he tends to do quite often . i don't think they'd charge $350 for it, unless it takes 5 hours to do. basically, when they do a computer diagnosis, all they charge you is labor time to hook it up to the computer. generally, to hook it up to their computer to check a CEL, they'll charge you the going labor rate of 1 hr (usually 60-75 bucks), b/c they just hook it up to the computer, then they are done with it. so unless they have to hook it up to the computer for 5 hrs to flash it, i don't think it would (or they SHOULDN'T) charge $350.

[Igovert500]

Hmm, interesting

1) possibly, I'm not sure, but it's possible

2) ECUs take at least 15 minutes to relearn, sometimes more, so a half hour, isn't unbelievable

3) Don't think you have more power, it might just feel that way. If you are idling a bit high, you will use a tad more gas, not much. Normal idle is around 700, so 800 isn't too bad.