Idle Surge

[StR8sPo0Ln]

OK, i was having idle surge. I switched ECU's and problem went away for a little while. Problem now comes back a little bit. I went under my hood because, my idle was sitting at 1500 most of the time. I turned the idle screw and dropped RPM's down to 800. This is all during freezing cold weather. I let my car sit and it raised RPM's back up again until it warmed up, then it dropped back to 950. Idle surge seems to be gone. Do i need to change my TPS?

 

[dsmjay]

check for boost leaks

 

[Echo5Zulu]

There is a good idle surge checklist you may like to read. I believe its on the vfaq.com very good list to go through to make sure you catch the problem. To much info on it for me to retype here. Good luck.

 

[JayRolla]

The TPS pretty much never go bad.

 

[Auto RS T]

Did you ground out both connectors when you adjusted the idle?

Idle adjustment link- http://vfaq.com/mods/BISS-1G.html

Here's the link to the idle surge vfaq. It should get you on your way.

http://www.dsm.org/how-tos/tttt/tttt3.html

 

[StR8sPo0Ln]

Did you ground out both connectors when you adjusted the idle?

Idle adjustment link- http://vfaq.com/mods/BISS-1G.html

Here's the link to the idle surge vfaq. It should get you on your way.

http://www.dsm.org/how-tos/tttt/tttt3.html

Idle surge has gone away now. Car now runs when warm at about 750 to 800 rpms. I think the problems have been solved. Thanks alot guys, and i never grounded the connectors didnt know i had to do so.

 

[merqury]

How did you fix it?

 

[StR8sPo0Ln]

How did you fix it?

I adjusted the idle screw.

 

[DiamondStarAwd]

I'm also having this problem. Car idles at 2k cold, then bounces between 1500-1800 when warm. Unburnt fuel is being dumped out the exhaust, I can see it and smell it on the ground. I have a throttle body off a 1990 car. Will that work. I also have a brand new oxygen sensor. After replacing those both it would leave it to be a boost leak or can the ecu be messed up?

 

[StR8sPo0Ln]

Im not sure if the 90 would work or not. I know you cant use the 90 trans on a 91 or above. and a 90 ecu is only good for a 90 car. but give it a try and see.

 

[Auto RS T]

A 90 TB could be installed...it is a little wider than a 91-94 style. You would have to hardwire the TPS sensor, so it isn't a plug and play operation.

Personally I would fix the 92 TB. Check your ISC coils resistance according to the vfaq link.

http://www.dsm.org/how-tos/tttt/tttt3.html

It sounds like you may also want to check that your IPS switch (Idle Posistion Switch) is functioning correctly too.

To do the tests you don't have to remove the TB, but while doing this you may want to think about replacing the TB shaft seals and BISS screw o-ring. They are most likely worn by now and could potentially be leaking boost.