Hey this is baffling me. Sometimes my 4l80e will shift into 4th early and lock the converter at low speed. The car is a 2000 pontiac trans am, has a pretty big cam, and a 4000 stall midwest converter. I've scanned the trans temp in hptuners scanner and it isn't getting above 140 degrees. Also when the scanner says to shift it shifts very quickly and the scanner commands lock and it locks. Which table do I need to change to get this under control. I'm shooting for not locking up til 65mph. Sometimes it commands correctly and sometimes it locks up early and won't unlock until very low mph.
Just saw your post on ls1tech also and I'm looking into this tonight. So far I've had nothing but problems and I have replaced the tps sensor so I'm guessing this is what the problem was.
Thanks for the help! I tried emailing bill@hptuners without any help and I didn't know where to start.
I just wanted to thank Russ K for the help. That was the problem and now no issues at all. Thanks again! I set the Max kpa in the engine diagnostic airflow tab to 100 and the Min to 0. Eventually i'll scan my values and then make the range closer, but for the mean time I can fully control the trans without the early shifting and early lockup issue. I had the same problem with my old 4l60e but I blamed it on an early version of hptuners. I since bought the new interface and then put the new 4l80e in at the same time. Looking back it wasn't an issue with the old interface but i'm sure this value caused the problem.
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