HELP! Can't figure out my high consistant idle.

[j_ro0703]

Hey guys. im looking for some help. i"ve got a 2g gst and i cant figure out my high bidle problem. i've been doig alot of research and and pulling my hair out. ok the deal im having is when my car gets to normal operating temp i get a high idle. varies from 1400 to 2500ish. when i start it after it cools its fine but as soon as it warms my idle turns to crap. ive replaced the tps,iac,fiav,ect and most of the most of the vacs. im not sure if i should try to replace the egr or block it off. ive scanned the ecu and it throws a CEL saying its a system idle controll malfunction. And saying a code of P0505. the IAC. it also said that the egr system is ok. oh ive tried to adjust the BISS too. Ive cleaned the throttle body and the throttle cable is not in a bind. So i really dont know what else to do... im still a nOOb so any advise would greatly be appreciated. thanx

 

[Smokin80]

If you have cruise control the little box to the right of the battery can be out of adjustment and cause this as well. Take the cover off of it(2 bolts) and losen off the cable on the right. I did this and it solved the same issue.

Also,
loosening the cable at the TB a little bit is good too. You dont want it tight because it will tighten a little sometimes and cause a high idle.

Easiest way to check if it is a sensor or ecu problem is to see if when it is idling high you can just manually turn the throttle plates back and it idles back down...then you have a too tight cable...adjust at one of the two points mentioned above and see if that helps.

Cheers guys,
Garrett

 

[j_ro0703]

ok ive looked in the FAQ's and the only thing i found that was close to what you were explaining was about terry's idle surge write up. ive read it before and it never said anything about grounding anything so im so confused. i apologize for any inconvience.

 

[j_ro0703]

can i see some pics of what you are talking about?

 

[j_ro0703]

i ment pics of the grounding, not the cruise

 

[meliketoball]

If it starts surging, then its your ISC! After, adjust the idle thru your BISS screw.

 

[j_ro0703]

i dont have an isc. i blocked off the bottom of my tb.

 

[romeen]

Did you try loosening the throttle cable like previously suggested?

 

[j_ro0703]

ok i will try.

 

[turboglenn]

My friend has this same issue so far we've tried

1.)Cleaning TB
2.)rebuilding TB
3.)New ISC
4.)Replaced TB with one from a known good running car - **** see thoughts on this at bottom
5.)replaced coolant temp sensor to ECU (his was bad causing an overfueling because it was reporting a coolant temp of -40) this only solved it for the warmup period of the car.
6.) checked and blocked all vacum lines that connect to the TB to test for oneof them leaking
7.) Made sure there was slack in the cable at the intake manifold
8.) Cursed at the car repeatedly and drank beer to cope with the stress of the previous 7 steps of failure


*** Notes on # 4 ... since we replaced teh whole TB ( ISC AND ALL) with one from a car known to idle good, i think that for some of you the problem does not lie in the throttle body but in some other part of the intake system or in the ECU it's self.

The things the owner hasn't tried that i keep telling him to do

1.) Plug off EVERY vacum line one at a time (including brake booster) to determine if the extra air is entering through some other un-found source

2.)Stop f&^%ing with the cooling system and concentrate on the first thing i said to do and that's # 1 above .

He thinks because it doesn't do it when cold that if he can make the motor run colder all the time he will get a lower idle (i don't get this, he's a smart guy but some of stuff he thinks will work is just plain "silly" to be nice about it ) I told him this would only be a band-aid if it did work, but he still want to try adn make it run cooler...not the answer IMO

Anyone ever found a bad brake booster on a DSM to do this same thing? I've seen it on some older V8 cars, but never on an import.

Either way, my point is i think we need to stop staring at the TB like something magical is going to happen to it and start looking in other places, if you took your car to the dealer for this they would have to get it fixed, and this would probably involve the use of OEM parts, NOT blocking off the FIAV (which i still don't understand why so many people do instead of just fixing what's wrong int he first place...with the exception of those who actually are doing it to get the HOT coolant away from their TB and drop those extra few ounces of weight that's needed in serious competition) but there's no reason your avrage jow should have to block off the FIAV just to get a normal idle, it just aint right i tell ya

 

[j_ro0703]

I finally found the problem. it was my throttle cable coming from my cruise to the tb. thank god. i happened to find it by luck tho. okay heres the story. took my car up to the local car wash. started idling high. go fig. so i came home and it was idling at 2300k. i popped the hood and jus looked at it for a min in disbelief. so i was looking it over and i happened to put my hand on the metal jacket that the cable goes through to the throttle body and, the idle immediately dropped! i was like woo hoo! then i got pissed ### of all that time i f'd with it and the embarassment i went through pulling up to stop lights and having people jus look at me like im an ass ### im holding the throttle. i want to give all ya'll a big thanx for helping me out!!!!

 

[romeen]

Good.

Now loosen the cable just a bit to keep it from recurring. There is a bracket bolted to the backside of the intake manifold held tight by two bolts (10mm heads). Loosen the bolts and move the bracket a hair to towards the drivers side of the car. If any questions about how to best adjust the cable refer to the post that I referenced in post #18.