IDLE problems - low idle, sometimes dies

[alIan]

symptoms: car started dying if i dropped in the clutch after boosting (didnt catch at 750+ rpm, just dropped to zero)

next, it started idling low, but would correct after about 15 seconds. (600 rpm)

now, it idles at 560-630 rpm constantly, and the engine seems rough... i can hear a clicking near the tranny area. i assume this is just because the idle is so low and it's not happy at that rpm (i'm hoping).

things you should know:
-cables and plugs were replaced by roy at RRE about 500 miles ago.
-installing the IC required removal of the throttle body (not completely, just bolts out). i didnt mess with the connections, but it could have thrown something out of adjustment... (IAC? TPS? throttle cable?)
-i have adjusted the BISS, and it did not help. i did not ground it.

basically, i'm asking where i can start to diagnose/cure this problem.

clean the throttle body? test the iac/tps? replace them? clean my MAS?

thanks for any help ahead of time.

ian

 

[alIan]

one more thing... when i'm not idling the car runs fine. it is only a problem down in the idle range.

 

[wingzgsx]

You do not have a lightened flywheel correct? I assumed not since you mod's list didn't not show it.

 

[alIan]

No lightened flywheel. I am going to try to test my ISC (assuming that it is the same as the 1g procedure on vfaq). Then i will try to adjust my base idle. I will need to find a way around using the diagnostic tool... anybody got a link? Just need to know what to ground and the procedure...



thanks

 

[oldman]

Are you venting? What's your vacuum and fuel pressure reading at idle?

 

[alIan]

i'm not venting... recircing greddy type-S back to intake.

my FP is 42 psi at idle (no vacuum line on AFPR... base)... with vacuum it's about 34.

i am pretty sure my ISC is just going bad. it's just a matter of it catching the right idle...

i also need to properly adjust the BISS screw, and really would love it if somebody could tell me how to do it without the diagnostic tool . shops in my town are full of pricks, and i dont wanna deal with asking them to borrow one. they would charge me a lot.

 

[oldman]

i also need to properly adjust the BISS screw, and really would love it if somebody could tell me how to do it without the diagnostic tool . shops in my town are full of pricks, and i dont wanna deal with asking them to borrow one. they would charge me a lot.

2G proper BISS adjustment procedure.

 

[alIan]

yeah i know oldman that's the link that says you have to have the tool . i was asking specifically what to ground to get around that... i've heard it's possible...

 

[alIan]

after doing even more research i tested my IAC (ISC) motor with a volt/ohm meter. The top row resistences (1-2, 2-3) were 22 ohms each, and the bottom row resisences were 20.5 ohms each... well below the 28-33 ohm limit. i'm pretty sure this is my problem. i'll be forking out 200 bucks at the dealer for a new one today

After taking my ISC out, there is extreme carbon deposits on it and in the passageway:

<img src="http://i13.photobucket.com/albums/a283/iseiple/Pre-Xmas087.jpg" alt="Image hosted by Photobucket.com">
<img src="http://i13.photobucket.com/albums/a283/iseiple/Pre-Xmas085.jpg" alt="Image hosted by Photobucket.com">

When i clean the TB with carb cleaner i'm pretty sure that this passageway does NOT get cleaned (duct tape covering the opening). What is the best way to clean it safely?