4l60e 2-3 flare and rev limiter bounce

[Mr. Pute]

Hey everyone. Long time lurker that has posted about J-bodies in the past. I've now got a Camaro with the following done to it:

http://www.j-body.org/members/mrpute/cars/5/

Yeah, yeah, I still use a J-body web site to host information about my f-body

Enclosed is my tune and a brief datalog of the problem. I wasn't exactly doing this on a closed course, so it was tough to get in proper runs. About 1/3 of the way through the log is the drop down to 2nd which then flares at the top, bounces off of the rev limiter, and then finally shifts into third. A little further into the log is a 1st gear to 2nd shift with rev limiter bounce, but I had to let off early due to the amount of noise I was making (1st gear is useless with my open diff and street tires).

Also, I'm currently in the middle of finalizing my VE table, so the MAF is disabled and the ECU is in open loop the entire time.

Any ideas? After doing a quick search, I found the following:

http://www.hptuners.com/forum/showthread.php?t=31195

I may try this tomorrow, but if anyone can see anything else wrong, I'd greatly appreciate it. Oh and the problem occurred even before I messed with any of the torque management.

Thanks in advance.

[Google]

you have your 3-2 shift set at 88mph and should be set at 74mph



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[Mr. Pute]

you have your 3-2 shift set at 88mph and should be set at 74mph



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I saw that too, but even a stock 01 Camaro tune I yanked from the repository on here has it at 86mph when scaled for 24.91" tires. It couldn't hurt to try though. Thanks for looking. I'll give that a shot tomorrow and post back my results.

[Google]

When your upsift is lower then your downshift the pcm trys to do both at the same time.



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[Google]

Guess it is Gooood now?







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[Mr. Pute]

Lol, I wish. Sorry for the delay. Here's a new set of logs and my tune. I tried doing what you said, but still the same results. I tried lowering the shift rpms and the 2-3 and 3-2 shift mph, but still no go. I also tried your excel spreadsheet to correct the VSS pulses and trans revolutions.

The 2-3 upshifts are at frames 3460 and 6300. Also, notice how the rpms linger and float down as if the shift isn't engaging completely for a rather long length of time. Normal driving around, it's fine. This makes me nervous...

Any other ideas? Thanks again for the help!

[Google]

for 3.23:1 gears 25.65 tall tires with the converter locked.. your shift mph is set to 5600 in all three gears..

1-2 @ 38mph your rpm will be 4950
2-3 @ 76mph your rpm will be 5250
3-4 @ 129mph your rpm will be 5475

If you flash it back to stock and still have the same problem then it is transmission related or Hard Parts.. If it does not fix it let me know..


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[Mr. Pute]

Enclosed is the "stock" tune that was pulled off of the PCM when I got the car all wired up. The car is actually a 98 with the powertrain and drivetrain out of an 01 WS6. Also enclosed is a stock tune out of an 01 Camaro that yanked off of the hptuners repository. Except for catalytic converter and fan temp changes, the tunes are identical.

Unfortunately, the stock tune was unmolested by me when I did my first runs and the problem was present then as well. Definitely not the news I was looking for, but I'm also not surprised. Thanks again for your help in diagnosing the problem.