Shifting Issues

[Pomp]

I have a 98 F-body with a 4L60E tranny that is not shifting properly. The 1-2 shift is fine but when it comes time to change from 2-3 it goes of the rev limiter twice before shifting into 3rd. The rev limiter for the engine is set at 6800 and the shift points for 1-2 is 6000, 2-3 I lowered to 5600 and it still hit the limiter. Any help with this would be appreciated and I have attached the tune. Can't figure it out unless my tranny is bad but I just had it built with heavy duty inners.

Attachment 1767

[Russ K]

Your 3-2 shift speed is HIGHER than the 2-3 shift speed @ 100% tps.
Don't zero the shift times, .250 sec. would be the lower limit.

Russ Kemp

[Pomp]

Your 3-2 shift speed is HIGHER than the 2-3 shift speed @ 100% tps.
Don't zero the shift times, .250 sec. would be the lower limit.

Russ Kemp

I fixed the shift times to .250 but as I see it 2-3 shift is at 76 and the 3-2 shift is at 72. Anything else??

[Bill@HPTuners]

37.00000
76.00000
125.00000
31.00000
86.00000
123.00000

thing is I've seen this stock in some fbody calibrations...not sure why. As far as why its hitting the rev limiter even with the commanded rpm at 5600 im not sure...what mph is 6800 rpms in 2nd gear in your car?

[klymaxr]

Hey Pomp i just posted the exact same thing!!! shows we both had the same issue at the track. Iwent throught my tables on friday before i left Autoworx and die find a cell that was higher kick down then up shift, but i fixed that and every thing was ok untill i di a pass on the nos. then it hit the limiter on 2-3 again, so at the trailer i lowered it even more and it just barely hit in 2nd. then on the drive home I kicked it down at about 40mph and it hit the rev limiter again in 2nd.... naturally aspirated...what the hell gives. Hope someone has an answer. we might have to increase line pressures or something???
Max

[Pomp]

I did some revamping so can you guru's pls have a look and tell me if I need to make changes or if you have any suggestions.


Attachment 1783

[klymaxr]

hEY POMP, I JUST GOT SUITE 2.1.12 HP TUNER AND I CAN'T READ YOUR SCRIPED, BUT I'VE BEEN SURFING FOR THREE DAYS TO FIGURE THIS OUT. i LOOKED AT YOUR SHIFT PROFILES AND THEY LOOKED OK. i THINK OUR PROBLEM LIES IN THE FORCE MOTOR CALIBRATION, YOURS DROPS FROM 151 @ THE FAR RIGHT COLUMN TO ZERO IN THE NEXT,USUALLY I.VE SEEN THE FORCE MOTOR SCALE GO FROM 8-900 OR SO IN THE LEFT COLUMN TO 96 IN THE FAR RIGHT THEN THE MAX VALUE IN THE BOX MATCHS THIS. AND WITH YOUR PROGRAM YOU HAD YOUR SHIFT TIMES AT ZERO, WHICH IS OK ONLY IF YOUR OTHER PRESSURES ARE CORRECTLY SCALED. THEY ARE NORMALLY AT A MIN OF .2-.250. SOME PEOPLE ARE SAYING THAT IF THE SHIFT RPM AND THE MPH ARE TO FAR OUT OF WACK FROM THE ACTUAL SPEED V RPM, THAT THIS COULD CAUSE OUR CONDITION.i THINK FROM READING ITS MORE TO DO WITH OUR PRESSURAND FORCE MOTOR SCALING CHECK OUT ALL RUSS'S POSTS ON THE TRANS SIGHT
MAX

[Pomp]

Max I hav HP 2.1.13 beta so if you want it I can send you the link to download it. Send me pm with your address in it.

[Pomp]

TT for more help please.

[usd2sing]

subscribed. same problem

[Bill@HPTuners]

what gears? looks like 3.73's maybe?

[Bill@HPTuners]

just an FYI I had a mint 00 with bolt ons today with a VERY similar shift point setup that was shifting at 6450...this setup looks quite a bit stronger from the looks of just the idle settings...its very possible your just overpowering the tranny enough to make it shift another 300 rpms late. Maybe consider setting your shift rpms & mph especially a bit lower on the 2-3 shift.

[Pomp]

Yes the car has 3.73 gears in it and the tranny has hardened and internals all upgraded to handle 600hp. I did lower it to 5500rpm and is still bounced off the limiter twice and then shifted. My engine is a 385 LS6 stoker that is putting down 425 hp and the wheels so traction on the street can be a bit of a problem. I tried to see if the shifts worked lastnight but just couldn't get enough traction to hold the road.

Any other thoughts and thanks for the help so far.

[MMGT1]

Mine was shifting nuts because of an air leak(Hitting the rev limit when should have shifted about 650 rpm lower). Just a thought, check around the throttle body, esp the IAC motor. Just a guess none the less

[Special K]

I've got a '03 Vette. It would not shift when commanded. I had to zero out all MPH upshift settingsi in Normal. Hot and Performance.

I also had to zero out the MPH in 'Part Throttle Shift' from 69% to 100% throttle position. I did this in Normal, Cruise, Hot and Performance. It now shifts exactly when commanded.

Hope this helps.

[Pomp]

Thanks Special K.

Would this work if I just took it too zero in full throttle and not in Part throttle?

[Special K]

Thanks Special K.

Would this work if I just took it too zero in full throttle and not in Part throttle?

Mine wouldn't work. Damn things have a mind of their own. Yours may react differently. I figured if it went to 69% I was gonna be on the floor anyway.

[klymaxr]

pomp, got mine working ok now, just revamped my whole shift patern and lowered my mph settings a little. but i also found for somereason my gear ratio got changed to 3.73 from 3.15??? don't know how that happened, i never went in to that file. Iknow i will have to lower it more when i do a nitrous pass thou.
max

[Billiumss]

I've got a '03 Vette. It would not shift when commanded. I had to zero out all MPH upshift settingsi in Normal. Hot and Performance.

I also had to zero out the MPH in 'Part Throttle Shift' from 69% to 100% throttle position. I did this in Normal, Cruise, Hot and Performance. It now shifts exactly when commanded.

Hope this helps.

Do you mean setting it to actual zero or 255?

Care to post the file for us to look at?