1995 Pontiac Trans Am 5.7 LT1 105,000 miles.
Normally, the rpms will stay up around 1200 if the car is at idle and you continue to roll. Once you come to a complete stop, the engine rpm immediately drops to 750 to 800 rpm.
The car operates correctly when it is cold; however once warm, it constantly stalls once I come to a stop. I have an air/fuel ratio guage that indicates no fuel or totally lean condition when it stalls. I can always crank back up immediately and it idles correctly untill I slow to a stop again. I can prevent it from stalling by working the throttle untill I begin to roll again.
I have changed the idle air motor which did not repair the problem. The engine has been built which includes a mild cam, heads, headers, larger throttle body, auxillary fuel pump, MSD ignition, and a pro-charger blower (+7.0 psi max).
Because of space limitations after installing the supercharger, I am using a smaller 13.8v battery. My mechanic has suggested that I install a standard size battery in the rear of the car. The car is getting harder to start and the starter labors to some degree. He believes that the smaller battery is falling below a certain voltage threshold while coming to idle after rolling to a stop which confuses the ECM. Does this make sense? (The battery measures 12.3v when the ignition switch is in the accessory mode).
Would you have any idea what may be causing the stall?
Normally, the rpms will stay up around 1200 if the car is at idle and you continue to roll. Once you come to a complete stop, the engine rpm immediately drops to 750 to 800 rpm.
The car operates correctly when it is cold; however once warm, it constantly stalls once I come to a stop. I have an air/fuel ratio guage that indicates no fuel or totally lean condition when it stalls. I can always crank back up immediately and it idles correctly untill I slow to a stop again. I can prevent it from stalling by working the throttle untill I begin to roll again.
I have changed the idle air motor which did not repair the problem. The engine has been built which includes a mild cam, heads, headers, larger throttle body, auxillary fuel pump, MSD ignition, and a pro-charger blower (+7.0 psi max).
Because of space limitations after installing the supercharger, I am using a smaller 13.8v battery. My mechanic has suggested that I install a standard size battery in the rear of the car. The car is getting harder to start and the starter labors to some degree. He believes that the smaller battery is falling below a certain voltage threshold while coming to idle after rolling to a stop which confuses the ECM. Does this make sense? (The battery measures 12.3v when the ignition switch is in the accessory mode).
Would you have any idea what may be causing the stall?
Aug 22, 2007 at 10:52 AM