Stalling issue at autocross

[SSninja]

Participated in my first autocross yesterday. :)

While nothing is permanently broken, I do have a new stalling issue to diagnose:



For those that don't know details on the car:

1987 Monte Carlo SS
SBC 350
Holley Stealth Ram controlled by a tuned '730 ECM
Used GN gas tank with a replacement GN fuel pump, newish (About 15,000 miles) fuel filter, and newish (Same mileage as the filter) fuel lines.
Small cap HEI ignition with an MSD 6A box

The car has NEVER had a stalling issue in the past when driving around town, but it didn't seem to like taking corners hard after the first run of each session.

For each autocross session, the first run always goes well, with the second and third runs resulting in the car bogging down and stalling out (Idle drops and you can "feather" the throttle to keep it from stalling, although that doesn't always work) when accelerating out of a turn/ through a slalom.

Initially thought it was a fuel starvation issue, only I know that the tank was 100% full as I just topped it off. Given that the tank is
a used GN unit and the fuel filter is a few years old, perhaps either one or both was getting clogged by sediment that was kicked up?


The car fired right up (Rolling restart as I lost power assist for the brakes and steering...NOT fun), within a few seconds each time this happened.

Also, the car didn't miss a beat when driving home, and I was getting on it hard once in a while to see if I could get the issue to happen when accelerating in a straight line. No issues there.

Any suggestions?

[anthonys 69]

The first thing I would do is rig up a fuel pressure gauge so you can see it clearly as you go around corners. It may have more to do with the throttle snapping closed after a hard acceleration. Can you check the ideal air control valve. If the throttle butterfly’s are all the way closed the ideal control valve will be nearly all the way open to obtain correct ideal speed.. As you drive the valve closes and as you stop the valve opens again to allow the car to ideal. May be fine for normal driving conditions but not for the auto cross the valve may be moving to slow. If so give the throttle stop a quarter turn, which will open the throttle butterfly’s you may have to go into the set up and adjust the ideal to new throttle position. Now when you snap the throttle closed there will be enough air getting around the throttle plates to stop the motor from stalling. Before the ideal control valve was opening to slow to give the motor the air motor needed and by the time you restart the valve will be open enough for normal operation. Good luck