need comfirmation of bad iac

[mustracetsi]

helllo guys. im need to the forum but lurked for time to time when i had a 420a motor. no after couple years im proud owner of a 97 talon tsi awd. 4g63 97k body about 1k on the motor. when i bought the car car ran fine. i had check engine light on. discounected the battery and cel pop right back off. noticed the rpms was high 1500rpms at park. so took the tb off and clean it up to see if it had carbon build up. clean out side of the tb filthy on the inside. clean it up. put all back together. started the car rpm ran up to 2k rpms. so i loosen the biss all the way retighten and rpms dropped back to 1500rpms. just need comfirmation from the pros that is the iac. with the biss loose would'nt the car stualled out. now my car is sputting. when i go mid way it hesitates. no i think my tps went or something cuase of the iac i beleave. any tips or insight i gladdly appreciate it.

 

[Captn]

Test the voltage on the iac. I think more problems with the iac include idle surge.

Do you have any tuning device or is it completely stock?

Try running the car with it unplugged and see what happens if you cannot test the iac.

 

[mustracetsi]

from what i can see looks stock motor wise except for the turbo x b.o.v, atmosphere not recerculated came like that when i bought the car, also 3a carbon fiber muffler, and rims

 

[eagle93tsi]

If you still have the check engine light get the code read. It could be the engine temperature sensor being shot and the computer thinks the engine is cold.

Otherwise it is probably a surge issue. This post has good set of tests to do to narrow down possible issues

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

If you do not find something with these tests it is time to do a boost leak test.

This post has some details on a boost leak test.

http://www.dsmtuners.com/forums/art...st-how-boostpro-net-tester.html#post152554139

Was you timing correct when you tried to reset the BISS. If not then your timing belt may need to be checked or the CAS needs to be adjusted.

 

[LiquidX]

Start with a proper boost leak test and test your IAC coils. There are some videos on YouTube with this information.

 

[mustracetsi]

thanks guys for the tips. i do have a cel for the aic. quick question about boost leak. i dont have the tool for boost leak. is it possible to do soap test to check for leaks without the tool meaning while the car idels or it has to be under boost.

sorry im don't know some of the abrevaitions. what c.a.s as for the biss. i lossen the screw and moved it all way to towards the tb to give it all its slack expecting to drop cause car to staul out but didnt rpms just kept on the 1500rpm.

 

[Captn]

You would suck the soapy water in if you did it with the car running because of vacuum.

Ask a friend if they have one or you can make one with a simple coupler and gauge.

 

[eagle93tsi]

There are various methods for checking for vacuum leaks with the car running.
using flammable items like carb cleaner or a propane torch (unlit) expecting the idle to go up when the leak is filled by the flammable fluid. Or spraying water that will fill the leak as well, again causing the idle to go up, much safer but not quite as effective.

This is similar to a boost leak test, but not quite the same, Vacuum leaks are big boost leaks that need to be addressed.

The boost leak is much safer as the engine does not need to be running and some leaks only show under boost.

Making one is not too tough using a PVC cap, rubber coupler, a low reading pressure gauge and a tire valve. Assuming you have a compressor and use quick disconnect fittings you can put the quick connect fitting in place of the tire valve. If you add in line something like http://www.harborfreight.com/brass-air-inline-regulator-68220.html you can use to not over pressure things while you are spraying soapy water to find the leaks.

If you choose to use the tire valve then you probably want to use a tire chuck like this http://www.harborfreight.com/tire-chuck-with-lock-on-lever-68267.html as it will stay put as you look for leaks.