1G 1991 talon tsi idle problem

[blkmiller]

My idle is crazy. When i start the car it jumps to 2000rpm and then slowly drops til the car dies. In order to keep it running i have to keep hitting the gas. Occasionally the idle is fine but that is very rare. If the car stays running without having to play with the gas pedal the rpms range from 500-1500rpm.. What could cause this?

 

[jimsgsx]

The iac could be bad or needs to be cleaned. Have you checked plugs, wires, and normal things? Check maf and wiring. Mine did that until i checked ecu and it was fried. Have you adjusted the biss at all. What have you checked so far?

 

[1990TSIAWDTALON]

Throttle shaft seals???? Any sloppiness in the throttle, any play up down or sideways. Also have you done a boost leak test? Just suggestions.

 

[Chumpaumpalumpa]

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

 

[shaunaskelson]

If your throttle body is extremely dirty or worn it will cause this issue on its own. Generally speaking though it probably will be your iac. At idle boost leak wouldn't cause this as you would still be in vacuum and the fact that when you give it gas it helps would suggest not boost related.

 

[blkmiller]

what is an iac? idle air control valve? I thought it was a misfire so i did a complete tune up on it plugs wires.. I replaced the throttle body with a new one cause the one that was orignally on it was cracked.. And how do i check the maf? The kid that owned it before me put a 2g maf on it. When i first got it the car was fine. I had to replace the waste gate actuator it was stuck in a open postition.. But now im having this crazy idle problem.. How do i do a boost test? and the kid before me installed a aftermarket boost gauge but didnt do a good job installing it..

 

[Chumpaumpalumpa]

read this
http://www.dsmtuners.com/threads/how-to-do-a-boost-leak-test.138569/

 

[blkmiller]

Is there a way to check if the iac is bad? And what is the biss? And in order to do a boost test i would remove the intake pipe from my turbo inlet and attach the tool?

 

[1990TSIAWDTALON]

There are some directions on how to check a iac I just cant find the the thread right now . BISS - Base Idle Set Screw and yes you would have to remove the intake to the turbo to do a boost leak test with a very easy to make tester, cost about 8 bucks.

 

[92AWDHX40]

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


http://www.dsmtuners.com/threads/how-to-fix-your-idle-surge-problem.191137/

 

[blkmiller]

What kind of adjustments do i have to do on the BISS? Where is the iac located? I apparently lost my repair manual.

 

[Chumpaumpalumpa]

What kind of adjustments do i have to do on the BISS? Where is the iac located? I apparently lost my repair manual.

turn the screw until it is where it needs to be

 

[blkmiller]

just adjsut the screw while the car is running to figure out where it needs to be?

 

[Chumpaumpalumpa]

just adjsut the screw while the car is running to figure out where it needs to be?

pretty much
www.dsm.org/how-tos/tttt/tttt3.html