I built this 80e for a friend. Fti 3400 stall. Trans shifts great on upshifts. If u try and make a 30-40mph wot hit it stays in second. Try and make a 60mph hit It stays in second no 1st gear kickdown with ecu controlling it. I've been a tuner for 10yrs so I've played with all tables for speed etc no fix.

Hear is the thing. If i open hptuners scanner and command a 1st gear at around 30ish mph it will go to 1st and will shift to 2nd when commanded. Its got me puzzled never had one do this. Any suggestions?

 

Sound like a question for the tuning section. But what does logging data say is being commanded. but based on your force command if the PCM commands it then it should happen.

 

It shifts great through all gears. Everything in scanner looks fine just no 1st as it should. Scanner shows 2nd like it's doing thin 3rd like it feels. At this point I think bricked ecu

 

My question is did you do anything to the AFL valve? AFL oil can effect downshifts. I ream every 4L80E's AFL bore for a larger valve..

 

If the scanner is showing 2nd then that is what the PCM is commanding. The PCM has no method to determine what gear the trans is in, No feedback or pressure switch for that.
It does have a manifold pressure switch but that only shows the manual valve position not the actual commanded gear.

 

I did the Reem the afl with a transgo valve. This thing has stumped me. I just tuned a 03 truck with a 60e yesterday. It was doing very similar things. Doesn't want to downshift at wot etc. I think I may have a issue with my hptuners or software. That's crazy 2 vehicles diff combos, diff trans etc doing similar things. Never seen this before.

 

I used to laugh at people that suggested bricked or bad ecu for stuff like this. ceramic film capacitors and silicon wafers should theoretically last 50+ years without issue. but i'm seeing this kinda thing more and more often on stock PCM's

I had my personal daily truck trans apart 3 times last summer chasing a lazy 2-1 at stoplights. AFL right? nope, after much horsing with it, I swapped in a different P01 and the problem was solved. Same OS, Vin, Serial etc...same TUNE FILE. just a PCM swap.

I know I'm crazy but I'm not *that *crazy.

 

https://www.sonnax.com/tech_resource...a-bad-computer