Idle Adjustment

[Blackmount]

So I have this Idle problem..

car insists on idling 1500-2000 rpms...when warm. cold its sometimes higher.

I've checked for vacuum leaks and I have found none.
I have the Biss Screw turned all the way in.
I've adjusting the Idle Timing, and can get the car to idle at 750rpms nicely but driving the car is next to impossible because it runs like complete crap set to low.

I thought if you ground the The Brown Terminal in the engine bay that is suppose to put the ECU in Basic Timing Adjustment mode. which it does (during this time the car idles in the 1000rpm range)

So I set my Base ignition timing to +9.5*
Shut the car off, undo the Terminals start the car again. Back to high idle.
So I ground that Terminal again AND pin 10 under the Dash which is suppose to set the car into Basic Idle Speed Adjustment Mode. So I set then adjust the CAS accordingly and get the car to idle 750 rpms..

but the problem is its adjusting the cars overal; performance too which I thought it wasn't suppose to do when you had both terminals ground? Am I missing something? Please help.

I've gone through many threads similar to this and clicked on many links about idle speed adjustment and most of the threads end without a answer, or the links r dead.

EDIT: I feel dumb, I found a thread today that I have yet seen, and figured out my problem right away... ever since Day 1 I have done Throttlebody Coolant Bypass's on all my cars, but I lived in TN, severe cold was not that big of a deal, so never much thought about it...

Till I found the FIAV/ISC Discussion thread and read this

"As far as I can tell, the FIAV works just like a thermostat. The valve expands with temperature (engine coolant) to close an orifice (air passage that bypasses the throttle body).

When you disconnect the coolant lines from the TB, like I did, whether you uncap them or not (I didn't), all you're doing is depriving the FIAV the heat it needs to close the air passage. With that orifice open, it doesn't matter what the ISC does, it cannot control the amount of air that flows around the closed throttle plate. The result? A normal cold-start idle and an uncontrollable idle surging at operating temp. At least, uncontrollable with my primitive e-manage blue (I can adjust timing and fuel)."

I noticed its not as bad when I park in the garage over night where it stays 20-30* warmer then it does outside, or on the nice days where its 35-40* Outside vs -10* Like today. So now reading that it makes perfect sense.

I' already went ahead and ordered the FIAV Block off plate so we will see what happens.. Hope this can be useful to anyone who has this problem in the future!

[Greg E]

Great job!

[dbest671]

Is this on the N/A TT conversion? Did you use a TT throttle body or N/A throttle body?

[Greg E]

Is this on the N/A TT conversion? Did you use a TT throttle body or N/A throttle body?

Both have provisions for the throttle body coolant lines.

[dbest671]

Both have provisions for the throttle body coolant lines.

Yes I know this... but I though he had a TT conversion and was using a N/A TB. The N/A throttle bodies don't have the reinforced shaft seals and cannot hold boost. Their shaft seals are nothing more than a rubber oring.

[Greg E]

Yes I know this... but I though he had a TT conversion and was using a N/A TB. The N/A throttle bodies don't have the reinforced shaft seals and cannot hold boost. Their shaft seals are nothing more than a rubber oring.

Ah I see.

[Blackmount]

I'm N/A with a TT Plenum, N/A TB

[Blackmount]

2nd time ive heard that and ive seem alot of cars run TBs from cars not meant for forced induction with no issues. high boost too. like 35+ psi

[dbest671]

I've bought N/A throttle bodies for parts, they have the same shaft, throttle plate, FIAV, and TPS... the shaft seals literally fall right out once you take off the spring plate and TPS plate LOL. They are very flexible, nothing more than an o-ring.

[R/T93]

Depending how the o ring is in there.... I have seen a simple o ring seal 7000+ psi.

From the phone.