PDA

View Full Version : 98 Pontiac Firebird WOT Shift



dmaxjm
August 14th, 2014, 03:46 PM
So my buddy has a 98 firebird formula. I ran a few scans on it because his trans was unable to shift from 2nd to 3rd at WOT. After looking at the cal, I reduced to timing for shift & took out torque reduction (he's planning on racing at the strip). We were still unable to shift. I checked the rpm shift, then set it to 5700 rpms and adjusted the vss to 77mph (vehicle was reporting 80 at 5700). Still no luck. Finally I adjusted the parameters for using the WOT shift tables, to have a lower and user threshold of 100%. I basically forced the trans to use the partial shift tables even at WOT. It shifted.... Anyone have any ideas on this and why it won't shift using the wot tables? The values were almost identical to the partial throttle shift tables. Anything helps! Thanks!

statesman
August 15th, 2014, 03:23 AM
Is his TPS reading 100% at WOT?

dmaxjm
August 15th, 2014, 03:27 AM
Yes it is.

statesman
August 15th, 2014, 03:46 AM
The 98's use a different operating system to what I'm used to... but if it has a {D0918} and {D0919}, then try changing those values to the speed you want to shift at. It might not help, but I don't think it will hurt anything.

dmaxjm
August 15th, 2014, 03:51 AM
I attempted the D0918 yesterday. Didn't seem to affect anything. I don't have the D0919. At first before I started messing with the cal, we threw the stock cal on it to see if the trans was fried. Funny thing stock cal didn't allow the shift. After messing with D1201, changing the upper threshold and lower threshold for wot shift mode to 100% (fooling the computer to use the partial) it worked. It was weird that a stock tune didn't fix the shifting. Almost like the PCM is just messed up somehow.

statesman
August 15th, 2014, 04:02 AM
It is possible that your operating system got messed up. Try downloading a stock file from Holden Crazy (tunefiledepot.com) and do a full flash with that file and then cal flash your calibrations back in on top of it. Again, might not help... but probably wouldn't hurt trying. If it doesn't help, then at least you'll know what's not causing the problem. :laugh:

dmaxjm
August 15th, 2014, 04:10 AM
Hahah. Yeah I have no idea what's causing the problem. I researched it a little bit more and it seems as if people say the PCM has something wrong with it and the way it handles the code between the mph and the rpms at WOT. Are there any negative aspects to use partial throttle shifting tables for WOT? I mean it works, but I feel as if it's just the wrong way to do things.

statesman
August 15th, 2014, 04:17 AM
I really don't know... I've never set up a transmission to shift that way, but if it works then it works. It's got to be better shifting on part throttle table than not shifting at all. He could always upgrade to a 0411PCM and use a later OS... which might be money well spent if he's going to run it at the strip.