Tuning question - Please Help!

[92stanglx]

I just got my new setup put together and am trying to get it dialed in so I can start driving it. Here's what I've got

- 92' LX
- 331 (9:1)
- TFS heads
- TFS stage 1 cam
- S-trim (8lbs)
- 24lb injectors (yeah I know way too small, but using for breakin)
- pro-m maf (calibrated)
- Gt-40 intake
- 255 intake w/ BBK inline pump
- APFR
- stock ecu

When I start the car it idles fine for a couple of minutes. After that it will start hunting for the idle (between 500-1100 RPM) and then eventually die. I have the initial timing set to 10 degrees. My fuel pressure fluctuates between 39 and 41 PSI.

What can the issue be? I am trying to get it tuned just enough so that I can drive it around and break in the motor.

[cannibalracing]

Check TPS Voltage, try higher or lower fuel pressure, and raise the idle.

Do you have the idle air bypass thingamajiggy. The one that sandwiches between the tbody and the idle air solenoid. If not, get one, they are cheap. And usually cure the hunting idle, by letting more air in with a closed throttle.

In the meantime, try cracking the throttle open with the throttle screw and resetting the TPS. This will let some air through. You have to do it in that order, the reverse order would give you a high TPS voltage at idle.

Timing is fine.

[92stanglx]

Is the idle air bypass the same thing as the IAC or is it something different? I have the stock IAC installed on the car.

[cannibalracing]

it is the IAC, but there's a little part that sandwiches between it (bypass), that guys use to tame the idle of cars with big cams, etc... I'm not exactly sure of the name and cost since it's a 87-93 part. Haven't owned a FOX in a long time and it's not necessary for SN-95's. The have one built into the throttle bodies, stock and aftermarket.

[wikdfst]

Pull out the plug to your clutch switch. Make sure you have a good ground to the battery. Make sure your battery is fully charged. Make sure your alt. is working properly. Sometimes it will surge as your charge goes up and down to your battery. There are many things that could casue a surging idle and most fox bodies without custom chips have that problem to some extent. (Modified ones anyway) Also did you have that problem before you installed the blower or when did it start???

[92stanglx]

Thanks for all the help everyone! I solved my problem by playing with idle screw and setting the TPS. I just wasn't patient enough :teeth: