1-2 upshift problems at 100% throttle

[gofish7]

The 1-2 shift at 100% throttle is not upshifting...however, it will upshift at 90% or if I let out of it a little bit....I put the stock settings back in from the rpm/mph shifting points. I lowered the shift time...I put it at .200 and wasn't a problem before I changed the rpm/mph shift points. 2-3 shift is fine.....just the 1-2 is messed up for some reason. Any help would be appreciated.

Note: 2002 Silverado Z71 265/75R16 tires with 3.73 gears. Fuild in transmission and filter was just changed and looked good on the inside. Fuild level is back were its supposed to be. Haven't tried the stock tune yet but wanted your opinions. Also note that I reduced WOT mph shift points down from 36 to 34 in the modified tune to help it shift...maybe.

[Russ K]

Try this trans tune, you had your force motor table higher than stock=LESS trans pressure. I set up your shift pressure tables & set up the torque management table to be 50% of stock. If you install a Corvette servo, the 1-2-3 shifts would be improved so you could zero the upshift torque reduction.

By the way, you have way too much spark timing. Note that the AFR spark table is adding spark to the already too high main spark tables. Then you lowered your base retard table a lot. With a 13.0 AFR, the most spark timing would be 24*.

Why are you commanding up to 11.33 AFR in PE?

Russ Kemp

[gofish7]

I read where 1.300 is 13:1 but mv wise its 920 mv at WOT with my VE table modified. So, a higher force motor = less pressure...I thought it was the opposite...which could be the cause.

Spark timing feels good with 0 knock..I can lose traction at a 20 mph roll in 1st but I've been going up and down...I know Nelson Performance put 36 degrees of timing in a LQ4 one time that made the max hp. But, I tried 28 and that tune that posted was 32...I need to G-tech it and see which one is better but I want to get this tranny thing fixed first.

This is on 93 octane with AEM Brute Force CAI and Corsa Cat-back.

I'll report back in a few hours with a tune update....thanks Russ.

[Russ K]

Commanded AFR in PE=Stoich/EQ Ratio vs. RPM. And you need a wideband to check/tune the WOT AFR. Your probably too rich, allowing more spark timing. First get your commanded & actual AFR to 12.75-13.0, then tune the spark timing.

Russ Kemp

[gofish7]

Yea I know about the wideband...I have one that I'm going to put in one of the rear o2 slots...I know the cats will mess with the A/F about a .5 of a point but if I can get it to read about 13.2 after the cats then that's roughly 12.7 at the engine for a good tune to move the wideband in front of the cats for a run or two just to confirm what I have and to correct if necessary.

Thanks for the PE tip by the way.

Russ, I have my 1-2 shift again....you are the man. I'll report back tomorrow with more results....I'm going to change my PE table tonight and lower the timing back to 30 from 32 for right now and then I have electric fans to install tomorrow as well then I get to tune away for a little while.

[gofish7]

Ok...PE is set to 1.13 for a 13.0 command A/F.

[Russ K]

If you really want to firm up the WOT 1-2 shift, install the Corvette servo. When I tune a vehicle, I install the wideband in place of the stock RF O2 sensor. This puts the pcm in open loop.

I would back your timing down to 24* before you melt your ring lands.

Russ Kemp

[gofish7]

Yea....I'm planning on a vette servo.

So, wideband in the front right o2 sensor....sounds good to me...I'll do that tomorrow for a few WOT pulls b/c performance mods are done for a while besides the fans.