D4u1

[tracy_s_1993_atx]

On Saturday, I installed the D4U1 ECU replacing the stock ECU. The vehicle feels the same, but does not shift as firm. I thought that the shift program in the D4U1 computer was supposed to be a little "firmer". I had a shift kit installed at the last rebuild and I can say that the 1-2 shift was real firm, almost harsh with the stock ECU. Now with the D4U1, the shift is softer, but not as soft as stock ( before the shift kit ).

So what are the differences? I had the H3Z1 stock computer.

Thanks,
Michael

 

[Axianator]

As I've noted to many people many times in the past, there are very few signifcant differences between the '93 H3Zx and '94-'95 D4U1 programming. In fact, it might surprise most people to learn that Ford actually softened the shift firmness programming with the '94-'95 D4U1 calibration (yes, you heard correctly - the '93 H3Zx actually commands more line pressure at all shift points than it's younger '94-'95 D4U1 brother). Thus, for a lot of people, many of these supposed "shifting improvements" are acutally in their head.

That said, you are not experiencing anything that is out of the ordinary. If you really want to increase the shift firmness and/or modify the shifting behavior of your '93 ATX, I would suggest that you consider investing in either an LPM or a TwEECer.