AE Tuning trouble and question

[Jesse]

All,

I am trying to get my AE dialed in and I keep coming up with a problem. (BTW, I am using MSnS-E code 029q2 w/ MT 2.25 Release).

When I put the pedal to the metal from a stop I am getting a stumble which lasts a fraction of a second. According to the evidence I am going lean for a split second and the AE isn't set high enough to compensate.

However, I have been trying two things:
1) Keep the duration static and just adjust the v/s and ms values to suit
(and)
2) keep the v/s and ms values static while adjusting the duration.

When I try #1 I can get the low to med acceleration engine responses dialed in pretty well, but when I really get on the throttle it seems that the mixture is fine but the duration is lacking, causing a stumble.

This led me to #2. Altering the duration allowed me to dial in the high acceleration engine response, but at anything lower the engine goes pig rich due to excessive amounts of fuel.

(I am actually having an epiphany right now which is telling me that, as I increase the duration, I should reduce the ms values in the lower acceleration settings to compensate for the extra fuel...)

Anyhow, the point I am trying to go for is that I wanted to see if I could mimic the pump-shot circuit of my old Holley 4-barrel which seemed to handle the acceleration enrichment requirements quite well.

The AE circuit of the Holley works like so (for those not acquainted with the Holley carbs). There is a small "arm" or bracket that is rigidly attached to the shaft that the butterfly valves are mounted on and moves in proportion with the application of the throttle. At the end of this arm there is a spring-loaded "piston" (or rather a floating, spring-loaded bolt) that pushes on another arm just below the fuel bowl of the carb - this is the accelerator pump lever.

When someone quickly pushes on the accelerator pedal the arm/bracket attached the throttle shaft pushes the floating piston onto the accelerator pump arm, and in conjunction with the pump-shot nozzles on the top of the carb extra fuel is delivered. The nozzles have a fixed orifice through which the fuel is delivered at a constant rate, but given the nature of the floating piston/bolt - which is allowed to move in proportion to the pressure excerted on the acceleration piston (so one doesn't pop the accelerator pump diaphram with the application of too much force) - the duration of the "pump-shot" is variable.

This allows for small duration accel shot durring light acceleration, and a long duration accel shot durring heavy acceleration. (The rate of fuel delivered and duration of the accel shot can be altered on these carbs by swapping in/out certain mechanical components and nozzels).

My question is this - is it possible to set up the software with a variable duration vs. a fixed duration? I.e.: Duration = function(TPSdot) or TPS position (TPS raw ADC).

This might simplify the AE tuning stage by allowing one to have one AE ms value while altering the period of time that this value is in effect - duplicating the behavior of a Holley carb.

(Please be nice - it is not my intention to make the MSEFI ECU system similar to a carb as this defeats the purpose of switching to the EFI system. I was merely making a comparison between a particular function of the MSEFI system and a proven mechanical AE strategy that has worked for decades on the Holley carbs.)

Thanks all!

- Jesse