engine idle issues help!!!!!

[mastadogg2]

Alright I'll start off by saying I have did everything there is to do with the throttle cable, IAC/ISC/TPS Sensors. I tested all sensors and they all were giving good ohm readings. I adjusted the throttle plate behind the intake manifold & adjusted with BISS. Nothing seems to be fixing this idle its either over 1k or when i start the car up it just dies from being to low. And say for instance I get the car running fine then the next day from having it sit over night it will be all out of wack again. Im just getting really frustrated and cant figure this out.. do I need a new throttle cable maybe? and yes a boost leak check was done and there is not 1.

 

[I-luv-em-all]

I don't know if this mod works for 2g's but it's worth a try http://www.vfaq.com/mods/BISS-1G.html.

Also do a compression check, a motor with low or uneven compression can also give it some weird idle sometimes. Also check spark plugs, fuel filter, timing.

 

[mastadogg2]

nah its none of that..

 

[sc2_ct]

Have you cleaned out the throttle body and the throttle plate? EGR? FIAV?

 

[mastadogg2]

yes i had the throttle body completely off and cleaned everything and no i didnt mess with the FIAV cause the screws were to tight to break loose and i doubt its that. i looked under my pedal assembly and i have alot of slack where the throttle cable goes to the gas pedal.. im thinking my cable is worn somehow and when the car sits the throttle shrinks and when it gets hot it expands or something..

 

[sc2_ct]

On my old 91 TSi I had a shorted wire in the EGR harness that ended up causing my idle problems, but mine was an idle surge, not just a high idle. When you checked the ISC, did you actually pull it out and see if the plunger was moving in and out? It's possible that even with the coil impedance testing good that there is something still preventing it from working correctly such as the shaft being seized or something.

Also, sorry if I'm repeating anything you've already tried, but when you worked on the throttle cable assembly, did you hook up a volt meter to the TPS to determine it's position?

To rule out the throttle cable slack, wait until you're idling and the car is warm and showing the symptoms and then get under the hood and pull on the throttle cable to ensure that the throttle plate is fully closed -- if it is, chances are that it's not cable related.

Just guessing on this since I've only done 1gs, BUT -- When I started to look at the vfaq for the 2gs I noticed that it seems to call for the dealer scan tool, so it's possible that the changes you made at the BISS are being ignored... here's the vfaq link:

http://www.vfaq.com/mods/BISS-2G.html

 

[mastadogg2]

Alright with the car warm and i can push back on the throttle butterfly and make the idle go lower and this is with no slack on the cable... almost as if my plate in my TB is leaking when its closed? would that cause issues or no?

 

[mastadogg2]

When i was cleaning the throttle body out i did notice when the plate was fully closed it was still slowly leaking some wd40 out of it like it was leaking around the plate... but would this cause issues?

 

[sc2_ct]

You mean that with the throttle cable completely released, you can still press back the throttle plate and that air is going past the plate? If so, it sounds like the throttle plate is sticking open a little bit. When you press the throttle plate all the way closed via the throttle linkage, does the idle drop to where it should be? If so you could try disassembling the throttle plate and shaft, and clean all the bores really well. You might need to replace the seals:

http://www.machv.com/throtbodseal.html

This link has a repair process for replacing the seals, as well as a test procedure to see if this is the problem.

http://ca.dsm.org/FAQ/tb-shaftseals.html