1G High idle, smoke tested, no leaks

[edged1g]

I am trying to chase down a high idle problem(among others). I got so fed up with it, I bought a smoke machine leak detector. I pumped the intake FULL of smoke(I could tell by disconnecting the PCV hose and see it pouring out) but saw NO leaks. I am stumped at this point. The BISS is all the way in and only gets the idle to about 1000-1100 rpms.

I also tried applying vacuum to the brake booster using a hand vacuum pump with the car off to see if it was a problem. I pump it up to 20in/hg and it held there strong without dropping off.

I am looking for ideas or suggestions at this point if anyone can help. I can't get the idle down!

 

[BurrowZ]

Well based on your tests you have narrowed down your problem to not being a vacuum leak.

Clearly you have air getting past your throttle body plate, which can only come from a couple places on the throttle body itself.

Make sure your ISC is properly working, check your throttle plate itself for dirt or anything keeping it open, or make sure it is not damaged. Also, have you messed with the FIAV at all?

 

[edged1g]

I tested the ISC and it seems to be operating normally. If I log ISCPos in link, its always zero, I am assuming because of the high idle the ecu is trying to bring down. The FIAV is blocked off using a blockoff plate. The TB was rebuilt by FFWD but i was not impressed by the quality of the work. But it is clean.

 

[92AWDHX40]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

 

[edged1g]

I am very familiar with that link. But I have tested my ISC, my FIAV is blocked, my EGR valve is blocked, the BISS in turned all the way in and I just looked at my throttle plate with a bore scope and there is barely a crack there, if at all. i also did a BLT. So I have basically eliminated everything i can think of that would be causing air to pass the throttle plate and it still wants to idle high. I am open to other suggestions or other ways to test. Thanks!

 

[92AWDHX40]

Throttle cable too tight maybe, idle isnt a easy fix it may take time.

 

[edged1g]

Throttle cable too tight maybe, idle isnt a easy fix it may take time.

I agree, this problem has been a massive pain. I really need to get it figured out adn am willing to spend the time checking things, I'm just out of ideas.

 

[mizak82]

Tell me about it man.. I am so annoyed at my intermittent idle issue.. idles fine on cold starts, but once i start running errands, turning the car on and off the wideband stops reading and is wicked lean and the car starts to almost stall, I have to keep turning the steering wheel to keep the revs up.. I guess Im taking apart my throttle body..

 

[Lou98GSX]

blocking your FIAV might be causing your high idle.

 

[edged1g]

blocking your FIAV might be causing your high idle.

How could blocking the FIAV cause a high idle?

 

[92AWDHX40]

http://www.dsmtuners.com/forums/newbie-forum/177292-fiav-blockoff.html

 

[edged1g]

http://www.dsmtuners.com/forums/newbie-forum/177292-fiav-blockoff.html

I read the thread, but I already understand how the FIAV works. Blocking it off can not cause a high idle. Idle is determined by the amount of ait allowed to bypass the throttle plate into the engine. Blocking off the FIAV eliminates one path that air can bypass the plate. There is no way blocking it can raise the idle, unless it was done incorrectly.

Also, just wanted to mention, i performed the 3 tests in the FSM to test the brake booster and they all checked out fine. I did this for two reasons, one to see if it was leaking and two, because of ANOTHER issue I am chasing down with the brakes.

 

[eagle93tsi]

When you adjusted the BISS did you check the timing before you started?

Was the timing correct? If not, you may want to check the timing belt to make sure it is all set correctly.

You have hit all of the intake issues I can think of. Valve timing was my next thought as causing your issue.

 

[elterror]

Let me know the results PLEASE im having the same issue! Would really appreciate it!

 

[speed_limit_5]

Have you tried checking the camshaft posistioning sensor couldve come loose causing your high idle jus suggestion also im needing help with my 1g dsm myself but stuck to probate member for now so if anyone could help me be greatly appriciated I have a 1994 Eclipse Stock turbo 4g63 that jus bought flywheel shattered trans got trans to replace but dont have top dirt guard and dont know where to begin to find one or the appropriate name for this part hunted ebay & craigslist any help again would greatly be appriciated


Thnx Jo§h

 

[umbralspace]

My Idle was high for a while, but it ended up just being a dirty throttle body that got stuck open from time to time. I hate Idle issues.

 

[Solace Lost]

Might be some debris keeping your tb from fully closing..

 

[nicks tsi]

have you checked your throttle position sensor?Is it throwing any codes?

 

[elterror]

i changed the FIAV on it with another one so i will update soon on the results, hopefully with goodnews!

 

[nicks tsi]

@ speed limit 5. do you mean the inspection plate?

 

[edged1g]

When you adjusted the BISS did you check the timing before you started?

Was the timing correct? If not, you may want to check the timing belt to make sure it is all set correctly.

You have hit all of the intake issues I can think of. Valve timing was my next thought as causing your issue.

No, I haven't checked the timing because I was trying to get the idle down before i set it.

Have you tried checking the camshaft posistioning sensor couldve come loose causing your high idle jus suggestion also im needing help with my 1g dsm myself but stuck to probate member for now so if anyone could help me be greatly appriciated I have a 1994 Eclipse Stock turbo 4g63 that jus bought flywheel shattered trans got trans to replace but dont have top dirt guard and dont know where to begin to find one or the appropriate name for this part hunted ebay & craigslist any help again would greatly be appriciated

Thnx Jo§h

The CPS isn't loose, i checked it. As for your parts problem, go to

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and download ASA-USA. Its the parts lookup program. Find the part you need, and call JNZ Tuning and order it.

My Idle was high for a while, but it ended up just being a dirty throttle body that got stuck open from time to time. I hate Idle issues.

Might be some debris keeping your tb from fully closing..

have you checked your throttle position sensor?Is it throwing any codes?

The last time i posted I was able to idle the car at around 900 or so, but this was with the BISS screwed all the way in. i hadn't worked on the car in a week or two, and my brother started it this past Saturday. He said it was surging again. It went from being "OK" to surging without being touched.

I put a new TB on this weekend with a welded shut FIAV, and all new shaft seals from Throttlebodys.com. I started it up and it was idling at 2000. But i noticed in link that the Idle switch wasn't working. This was late last night and i didn't get a chance to try and simulate it.

With an idle this high I don't think it can be timing related(correct me if I am wrong). There has to be a leak somewhere, but i can't find it. I am open to other ideas.

Also, I am sorry for not replying with more frequent updates, but i was frustrated and thought the thread was dead. I have subscribed now and will get emails on updates and I will respond. I am also willing to help anyone however I can.

Just a quick list of things I have done:
smoke tested the intake at TB elbow - NO leaks
Turned BISS all the way in
Applied vacuum to the brake booster -held 20in/hg
New ISC from DSMISC
New TB from TB's.com with new seals
Welded FIAV shut
Blocked off EGR valve
Replaced injector seals

 

[yfjumper]

I know you can use a small propane torch that's unlit and put it up to all the vacuum lines and hoses to test a leak while it's running. But if you've already done a smoke test then I don't know what to do. I'm having the same problem my 1991 GST is idling at 2,000rpms rights now! sometimes it will lower to like 1,300rpms.

 

[BIG boost tech]

Do you guys have cruise control? I found one of my cruse cables loose. After getting is properly adjusted i had to reset my throttle cable. Does the idle change is you "pull back on the throttle body butterfly (light pressure in the other direction of the way the throttle cables would pull)

 

[1gslotsi]

I know on hondas adjusting tps will change idle could this help

 

[BurrowZ]

This is going to sound stupid, but how much slack is there on your throttle cable? When the engine bay heats up, it tightens the cable causing it to retract on the TB a little bit.

This is strange. You really shouldn't be getting an idle that high without air getting past the throttle body.