I would post the results of my logged AFR, but my laptop took a turn for the worst...

Here is what I am seeing and I was wondering if someone could explain the proper way to approach the problem.

Most likely I will not mess with the fuel for this engine, but will definately need to know for the new 406 that is gonna be getting placed in the car.

OK here is the situation:

Through the 1/4 mile my AFR in 1st gear goes from ~11.4 up to 13.1 then after the second gear shift the AFR drops back down to ~12.2 and climbs to 13.1. For 3rd gear it stays dead nuts almost flat at 12.7.

My question is why wouldn't 3rd gear do the climb too? Is it because it takes longer to go through the RPMs there, or is it due to the fuel pump not being able to keep up in the first couple of gears? For the 406 I will definately be upgrading to a better pump.

The car ran a 12.8x all day long saturday at e-town. The rings are leaking up to 50% on the one cylinder, that is why I am gonna be getting the 406. I would however like to hear what you guys think about the climbing AFR, so if the same AFR is seen on the 406 I know how to attack the problem.

Guess I was thinking the AFR for all 3 gears should look the same. Let hear what you think!

thanks guys!:hail:

 

About every car I've put my wide band on I've noticed that at shift change the f/a ratio will dip by about 1, then climb right back up to where it was and stay there till the next shift.
I have seen some small differences in the amt of f/a ratio drop at shift change between the gears but; yea, why does it do that?
Your changes sound like a bit more than I've seen, but the trend sounds pretty typical from what I've seen on a real world wot pass.
Lots different looking from a dyno one gear pull.....

 

Probly has to do with a load change on the engine for that split second when the shift occurs, unless maybe its hitting a leaner WOT area in the % table? Say your wrapping the motor out to 6200rpms and after the shift it goes back to 4800 or 5xxx rpms, maybe a lean spot there?