Originally Posted by FeetDry
I copied the PT/kickdown tables into a program called DPlot, and then played with the shading feature... attached is the .grf file if you're interested.
I copied the PT/kickdown tables into a program called DPlot, and then played with the shading feature... attached is the .grf file if you're interested.
Last edited by joecar; August 16th, 2012 at 05:05 AM.
Digging up old but helpful thread, have a hanging 1>2 shift that sometimes requires me to lift in order for it to shift, usually when I am peddling it out of the hole or starting from a roll and on and off the gas to get the tires under control. 100% across the board on the next tune and we'll see if it cleans it up. I like my valvetrain intact...
Hi JM, if you get it working, post the before/after tunes.
No Such Luck, did it again last night but didnt catch it in the act. I have a log a couple weeks old, not the same tune as posted but basically the same. here is a log of it doing a full throttle shift good and then missing the shift.
Note, my set-up is a turbo blow through carb 99 c1500. The TPS I use only goes to 88% when it is at wide open throttle. 30% throttle is very light cruise, 50% throttle is a good hard pulling out into traffic type of acceleration, 85-88ish is wot. I currently have my kickdowns at 100% which should be unattainable but it still acted up last night.
Problem seems to be rolling hard acceleration or when tires spin out (raising mph on the vss) most likely doing a 1-2-1 shift when I pedal it and get it back to wot. Oddly I noticed delivered engine torque drop to 0 at 5600 rpm, though it should never have been there in the first place (should figure that out for when I raise my shift rpm).
Any suggestions would be appreciated.
Hi JM,
the problem is this:
your WOT downshift speeds are above the WOT upshift speeds... they should be below (at least 5 mph lower)...
set D0925-7 below D0910-2,
set D0930-2 below D0915-7,
set D0935-7 below D0920-2.
Same applies to the part throttle downshift/upshift tables (the downshift should be below the upshift at each corresponding throttle position) .
Last edited by joecar; August 17th, 2012 at 12:54 PM.
BTW those WOT upshift speeds are quite low...
Awesome, easy to fix! I didnt even notice the wot downshift speeds, I did make the upshift speeds low so it would always be satisfied easily and use the rpm for the shift point. Need to sit down and fix a bunch of this stuff, I rushed the trans in and kept changing stuff on the truck and never took the time to hone the trans tune.
Is it easy to figure out why my torque number drops to zero at 5600, it sent shift pressure down to 43 which will not be good when I start shifting this thing higher...
Thank you so much for figuring this out for me!
I see you have all the fuel cut offs set to 5600.
ahhh-Ha! Awesome again man, that would have taken me days to figure out (if I ever did...). Thank you!!!!!
Hi JM,
the problem is this:
your WOT downshift speeds are above the WOT upshift speeds... they should be below (at least 5 mph lower)...
set D0925-7 below D0910-2,
set D0930-2 below D0915-7,
set D0935-7 below D0920-2.
Same applies to the part throttle downshift/upshift tables (the downshift should be below the upshift at each corresponding throttle position) .Joe you know I'm in no way trying to step on your toes as you are the master with this stuff but those shift tables he posted are stock. And every truck based 4L80E tune I've ever seen have the downshift speeds higher than the upshift speeds so I wouldn't say that is the issue. Suppose it makes sense too. It can't downshift unless it already upshifted first, correct?
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