Idle Surge and Fast Idle

[B Mad]

Ok so being new I will try to explain this the best I can.

Ok I had Idle surge due to a bad leg on my IAC so I adjusted my TPS until surge no longer happened and just idled at 2k as soon as I put into drive RPMs drop to 1k and seemed to run ok. Not great but ok enough to drive to work. I went and bought a brand new IAC and installed. Now my car Idles at 3k and wont drop. I adjst my TPS and I still get idle surge. And when I adjust my BISS valve it does nothing. Any ideas on what I can do? I should also add when I had my bad IAC valve in my CEL was on and when I installed the new one is in Im not popping any codes. The code I was getting was Idle Air Control Malfunction I believe.

The car is a 95 Eclipse GST.

Thank you in advance for your help.

Ok Im not a mechanic but Im really trying to learn. I just went out and was screwing with the car and when I disconnect the MAF it idles normally but does run rich. This is with the old IAC in. Could my TPS be bad and the MAF need to be cleaned? Someone has to have some advice for me.

 

[eagle93tsi]

There are many things to check and work trough. This post has a good set of starting points. Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

My guess is that the throttle closed switch may have been disconnected and this is causing the high idle.

You may have a boost/vacuum leak as well. Here is a good post on testing http://www.dsmtuners.com/forums/art...st-how-boostpro-net-tester.html#post152554139

 

[B Mad]

Ok so when i disconnect the tps nothing happens. When i reconnect nothing happens when i go to adjust the tps the idle dips down a little then stabilizes right back. When i turn on the AC the idle goes from 2k down to 1200rpm anyone have any ideas?

 

[thereef]

I battled with idle surge for a while until I did the free FIAV block as displayed in this thread (http://www.dsmtuners.com/forums/articles-intake-exhaust/391977-free-fiav-block.html)

My car now starts at 500rpm, and rises to ~850 solid after a good 15-30 seconds of warmup.

 

[300hpbound]

Definitely check for vacuum/boost leaks. My car did the same thing when a plug off of my intake popped out. Rev all the way to 3k and bounce for 10+ minutes. Go through that boost leak vfaq thoroughly and check every vacuum line.

After plugging the leak and (as Thereef said as well) doing the FIAV blockoff myself, idle sits at about 1100 when initially started and warms up to about 900 after 5 minutes.

 

[B Mad]

Thank you guys. I will take a crack at it again this weekend. Is doing the block off difficult to do for a newbie?

 

[300hpbound]

No it's not. Very very simple. I did mine while I was flushing the coolant out. There's two hoses that run to the bottom of the throttle body that contain coolant. If you drain your coolant even just a little I don't think you should have too much come out. When you pull the throttle body just make sure not to toss it around and you'll be fine. The write up is very informative and yes, it really is as easy as it looks/sounds: http://www.dsmtuners.com/forums/articles-intake-exhaust/391977-free-fiav-block.html

Just make sure to seal up the freeze plug with some rtv (If you have access to a Toyota dealership they sell some stuff called FIP that I swear by, seals everything the first time, everytime.) And make sure to grab a new Throttle Body to Intake Manifold gasket before doing it. The one that comes off is usually dried all to hell, and even is the cause of some idle surge itself sometimes.

You also may have to adjust the idle a bit after you do it, which is something that I'm still playing with myself. I don't know the process for the 2g idle adjustment, maybe someone can chime in or do some searching.

If you need a hand feel free to PM me but you shouldn't have an issue as long as you have the guide in front of ya. Only took me about 30 minutes

 

[B Mad]

Awesome. Anyone know where i can buy the block off cheap? And whats better? The block off or bypass? Also after doing this will rhe check engine light come on permanently. And last of all will the car be able to pass emissions test?

 

[Chevy2g3]

Another way to try to fix the surge is to disconnect the IAC and while it's disconnected adjust the BISS until the idle drops and settles. Once that happens plug in the IAC connector and you should be good to go. When I replaced my head a few weeks back I had the same problem. Before you do that though do check for for vacuum leaks and fix those first.

 

[B Mad]

Yea. I tried doing that my biss is all the way screwed in and still no help

 

[B Mad]

Awesome. Anyone know where i can buy the block off cheap? And whats better? The block off or bypass? Also after doing this will rhe check engine light come on permanently. And last of all will the car be able to pass emissions test?

Can anyone please answer this for me.