Different take on Fox idle issue

[Andy@PrimeTuning]

The ECU works quite well

A simple answer to your problem is. There is a learned idle airflow number at idle but not while moving

[Andy@PrimeTuning]

Timing effects it as well

Idle timing vs coasting low load timing

[Diabolic]

I didn't realize fox ecms had that. Never messed with a fox ecm. So do you have to lower the values allowed by the IAC? Do you need to lock out the timing for the times when conditions for idle flag are met? Is there something that allow you to chose the mph for which idle mode is activated? I've had several fox cars with heads and a big cam but never had the idle hang like that. Now my 94-95 cars all did it. Why would his fox be doing it?

[FastFox]

Andy @ Prime Tuning

Thanks for the comment about no memory when rolling. I did install the Ford IAC Bleeder plate, and it did help some. When warmed up and sitting still the car will idle at about 750 RPM's which is OK. During coasting withe clutch in, it still idles at about 1200 RPM's. I am set at 15 Degrees as base timing. I get no pinging, and I run 93 octane fuel. My motor is an 8.7 motor which is lower than most. So, am I timed too high as base ? Also, does the vss do anything on an A9L ECU ?

[Skidonenko]

From the eecIV probst boke the vss is part of the cruise, and idle control. Specifically on the iac:

"Important to oporations during deceleration from cruise or WOT. When you take yoir foot offthe accelerator, the unit allows extra air intake. This reduces emissions during deceleration, and prevents engine stalling"

Stalling issues, might be taken care of with the idle bleed. I dont see where it could hurt to dissconnect the vss and take it for a spin. Do you sill use the cruise control? If you had a newer aode then you'd run into shift/converter clutch issues but with an aod/manual its not an issue.

[FastFox]

VSS on a Fox car

I hardly ever use the cruise control, but it does work. I thought about just unplugging it like you said. I owned an old Nissan 280 years ago that had an on and off switch for the cruise along with the set and resume ans stop controls. If unplugging the VSS solves the high idle, I might splice in a toggle switch so you could use the cruise with the switch in the "ON" position. Like I said, I hardly ever use cruise in any vehicle I own. I guess I just like to be "In Control".

[FastFox]

Disconnect the VSS on a 93 Fox

I unplugged the VSS last night and now when you coast with the clutch in, the idle drops back to about 900 RPM. I think the problem is solved. Tonight I will go back and re set the base idle, and I bet the idle will drop to 750 RPM. I guess I might just live without the cruise control. Or, I may splice in a toggle switch that will complete the circuit in the on position if I decide to use the cruise. And, before anyone suggests a new VSS, I already installed on. I will admit that it is not a genuine Ford part though. I think it is a Borg Warner. I am a believer in genuine Ford parts whenever possible. I may go ahead and buy a real VSS and at least give that a try. They are not high. But, the drivability at low speeds is a lot better. There is no bucking because the idle is high enough to pull the car. I guess we just have to admit that Foxes are strange.

[Skidonenko]

That is the strategy t is supposed to have, dont swap the sensor again. Pickup a copy of the probst book for some good ecc iv info.