Originally Posted by swingtan

Further to that....

• B3406: Impact Factor
  Is a fuel correction "adder", so it increases the amount of fuel injected. It is calibrated via ECT and MAP to allow for different corrections based on temp and load. This table tends to have greater influence on smaller throttle movements rather than slamming the throttle open.
  
• B3401: Evaporation Time
  Tells the PCM how long it takes for the fuel left on the wall to make it into the intake charge. Again, this is a "correction" factor, not an actual figure for the evaporation time. Higher numbers here will extend the time that B3406 is used for as it indicates a longer evaporation time correction is needed. again, it tends to have more influence on smaller throttle movements.
  
• B3426: Stomp Compensation
  This tells the PCM to inject additional fuel when jumping on the throttle. Think of it as a pump jet in a carby based engine. As would be expected, bigger numbers = more fuel.
  
• B3428: Stomp reduction
  This tells the PCM the rate at which the "stomp compensation" is ramped out. Higher numbers result in a raster ramp out.
  

So for a lean tip in, I would look at....

1. Increasing B3426 to give a slightly rich spike at tip in spike
2. Adjust B3428 to blend the rich spike into the normal commanded fuel. Fir the spike goes, rich-lean-commanded, increase the factor to stretch out the rich spike. If it stays rich too long, reduce the factor to lean it out quicker.

For the rich spike at throttle close....

I wouldn't worry as much, but it can cause issues if you are running CL and the STFT's pull lots of fuel just prior to the throttle being snapped open. You could try reducing the values in B3406 and B3401 for the cells effected. This would normally be in the very low MAP cells, but may need some correction higher up to "catch" the rich spike earlier on.

If you really want to try it out, you can also mess with the Injector timing to mess with dynamics. The basic rule here is...

• the earlier the injector fires, the more time the fuel has to evaporate

So an early injector event results in more of the fuel being used for the intended induction event. ( IE. less fuel left on the wall )

I've done some testing with firing the injector just after the inlet valve closes. Doing this you can pretty much zero out the impact tables, but you may also miss time the throttle stop fueling as the injector has fired before the PCM signals it needs stomp fuel.

I've also fired the injector as the inlet valve opens, it makes the stomp fueling pretty good, but needs lots of work on the impact tables to get things working.

Also remember that at full song, the injectors will be open for longer than the inlet valve is open......

Simon.