Automatic transmission problem

[onzippy]

My unprofessional gut opinion is still telling me rev limiter, which would be good because it would mean your transmission is fine.
If you deliberately plow it right up to redline you'll see what I mean.

If your buddies with your tuner talk to him about it and discuss raising the limit ~200rpm and test again in D.

My current theory is the momentum from the extra power is spinning up the engine just past redline during the AT shifts?

[Styx]

Originally Posted by onzippy

My unprofessional gut opinion is still telling me rev limiter, which would be good because it would mean your transmission is fine.
If you deliberately plow it right up to redline you'll see what I mean.

If your buddies with your tuner talk to him about it and discuss raising the limit ~200rpm and test again in D.

My current theory is the momentum from the extra power is spinning up the engine just past redline during the AT shifts?

Okay but why does it do the same when in drive ? So it cant ba a rev limit thing

[onzippy]

Originally Posted by Styx

Okay but why does it do the same when in drive ? So it cant ba a rev limit thing

What I said. You've got a more powerful engine the TCU doesn't know anything about. TCU has yet to be cracked.
Even in D the TCU says: "Shift Now!", but the engine is still riding that extra FI through redline as the transmission is working on the shift.
Then the ECU is like "Oh Crap, what just happened? Better cut the power to keep from blowing".

I don't know bro....My comments are all theoretical.
Here's some chat about the same with some stock, high HP cars.

http://www.challengertalk.com/forums...69/index2.html


http://www.corvetteforum.com/forums/...-one-else.html

[WHITE]

Originally Posted by Styx

We keep our foot planted in the video we never take it off it just engages when it wants too.i do have logs with ecutec software but that is at the guy that does my reflashes.

Apologies, i must've miss read something or confused myself with a different thread.


In any case, you should definetly look at the logs before jumping to any conclusion from us here. As you can see some are saying granny problem and some are saying engine/ecu, so your not going to get a clear answer.

Do you have an afr gauge in the car?

[KoolBRZ]

The a/t doesn't have the same rev limit as the manuals have. It hits hard. The OFT guys change it by copying the limit from the m/t tunes to make it a "soft" limit. I strongly recommend having your tuner at least copy the rev limit from a m/t tune to your tune. That could fix the problem right there.

[HaloFRS]

Originally Posted by Styx

Okay first of all the car has a Sprintex stage two on and then normal headers with de-cat and then just a normal cat-back exhaust.It has a stage 2 flash from delicous tuning and we have swapped 3 diffrent tunes so we know it is not the tunes.

Now the problem is when i give it the beans,the car seems to select the next gear but doesn't engage it almost like a manual has it's clutch in and revving it.

So did you get it fixed?

[Weapon86]

I have a vortech SC on A/T as well. I was running on delicious tuning remote tune and after 3 revision, i started to have the same problem with whats happening on the video. But after getting the car dyno tuned, shifting went really smooth and they squeezed out more HP.

So unless youre certain that theres a problem with the transmission, i would get it dyno tuned. I THINK theres something to do with the shift points as stated above post. Its like getting a tuxedo tailored exclusively for you (dyno tune) vs buying a ready made ones (remote tune/ off the shelf tune) lol

[KoolBRZ]

When I had my SBD turbo, I was using OFT tuning, and I had a very similar problem. I talked about it with Chris of SBD and he said something like "All the other automatics used Ecutek tuning and didn't have any shifting problems." From this and other inferences, I would deduce that neither Delicious tuning, nor Open Flash tuning have access to certain tables or inputs that Ecutek has, and since it only happens with FI, it probably has something to do with the MAP sensor, or with manifold pressure limits. Dyno tuners usually use Ecutek, so that's why dyno tuning usually fixes the problem.

[Weapon86]

I forgot to mention when i got my SC, i was asking openflash if they can give me the tune for the OFT300. They were concerned about the shifting smoothness so they end up not sending me the tune. Although OFT is really convenient and it can monitor lots of parameters. I had to switch to ecutek to get the most out of the FI setup. DD drivability and flexibility when it comes to tweaking your setup, ecutek is the way to go.

[Wingnut537]

I'm experiencing the same issues with my auto trans and FI, kraftwerks c-38 running E85. Anytime I'm above about 8 PSI it feels like the clutches are slipping. I'm Ecutech turned (remote by motoeast).
I'm thinking about replacing the valve body, clutches, and torque converter with SSP but that's a lot of money to find out it is an electronic issue not a mechanical one.

[liquidsky44]

I'm having the same problems as well. I'm running the AVO kit and under hard driving the rev would climb but the wheels are not moving and the shifts are really slow. Need to back off the throttle before the gears are engaged.

[Tiz]

1.
"Kris @SSP has been seeing a lot of A/T failures lately under boost. The bad part is that some of the failing parts aren't available anywhere but from a donor tranny."

Do you have any more details? What parts have failed?

2.
I have an Ecutek-tuned GTX28 AT with map switching. The first map has approximately 370nm of torque. All is fine. The other maps have more than 400nm of torque. If I accelerate hard, it seems that the clutch is slipping. Moreover, check engine lights are shown. I read out the error codes:

C1294 = ECT System x Function
P2757 = Torque Converter Pressure Control Solenoid Circuit Stuck

Does anyone have experienced the same issue (including check engine lights)?

3.
Initially, there were reports from tuners that they run their AT with 450 whp. They did not report any problems. Does anyone know how they solved/avoided the problems mentioned in this thread? Or did they simply not tell us about these problems.

Thanks.

[skye67]

[FRSBRZGT86FAN]

Originally Posted by Styx

Okay first of all the car has a Sprintex stage two on and then normal headers with de-cat and then just a normal cat-back exhaust.It has a stage 2 flash from delicous tuning and we have swapped 3 diffrent tunes so we know it is not the tunes.

Now the problem is when i give it the beans,the car seems to select the next gear but doesn't engage it almost like a manual has it's clutch in and revving it.

I will say this though, it sounds awesome