Delayed Upshift at WOT, TPS only reading 89%
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From: Harpers Ferry WV
Delayed Upshift at WOT, TPS only reading 89% Hey guys... had the car out this weekend and ran some logs on it since its been acting up. Ive been having a problem with the 3-4 upshift. My tune has target rpm for 3-4 upshift at WOT set to 6200, Motors winding out till about 6500 before it shifts and when it comes in its a very violent upshift. The cars still making good power everywhere else in the band but after 6300 it falls on its face.
When we went back and looked at the log file however wide open is only reading 89% throttle opening. I checked mechanically and can see that throttle is physically opening 100% with the gas on the floor. I also know TPS has alot to do with transmission upshifts under WOT... Any insite here guys? Is there a diagnostic I can do to determine of the TPS is bad or out of adjustment? Any thing else I should look at? I know VSS could play a role here too.
BTW this is a 24x converted LT1 running a 02 LS1 F-body PCM
Cost me a race to a Fox body what was deffinatly beatable...
When we went back and looked at the log file however wide open is only reading 89% throttle opening. I checked mechanically and can see that throttle is physically opening 100% with the gas on the floor. I also know TPS has alot to do with transmission upshifts under WOT... Any insite here guys? Is there a diagnostic I can do to determine of the TPS is bad or out of adjustment? Any thing else I should look at? I know VSS could play a role here too.
BTW this is a 24x converted LT1 running a 02 LS1 F-body PCM
Cost me a race to a Fox body what was deffinatly beatable...
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From: Ann Arbor, MI
First, at WOT, the trans will only shift when BOTH programmed RPM -AND- programmed speed are reached.
However since your TPS was at 89%, the WOT tables probably were not used at all and the shift was according to the partial-throttle speed table.
There is a programmed parameter which specifies the TPS % to be considered WOT.
Sorry, I don't know the details about adjusting the TPS or if the PCM can learn its WOT value. You might start by logging the TPS voltage. IIRC, the closed (0%) voltage needs to be between .15 and .45 volts or the PCM is confused. The tuning section of the is forum has lots of threads on "fixing" the TPS values.
However since your TPS was at 89%, the WOT tables probably were not used at all and the shift was according to the partial-throttle speed table.
There is a programmed parameter which specifies the TPS % to be considered WOT.
Sorry, I don't know the details about adjusting the TPS or if the PCM can learn its WOT value. You might start by logging the TPS voltage. IIRC, the closed (0%) voltage needs to be between .15 and .45 volts or the PCM is confused. The tuning section of the is forum has lots of threads on "fixing" the TPS values.
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From: Harpers Ferry WV
Hmmm. so if the computer isnt seeing WOT or what it considers to be WOT it goes off the regular shift tables? An update: Just ran another log with the engine off and it did actually hit 100%. Im guessing im subconsciously not pressing the pedal down all the way when I'm logging.
So in regards to the fact that under WOT condition... my programed RPM for 3-4 upshift is at 6200, and the speed is at 128... Both these conditions have to be reached to signal upshift? Seems odd to me since 6200 is way before 128mph. So how do I calculate the proper shift speed? 6200 seems to be the sweet spot because above that the performance tapers.
So in regards to the fact that under WOT condition... my programed RPM for 3-4 upshift is at 6200, and the speed is at 128... Both these conditions have to be reached to signal upshift? Seems odd to me since 6200 is way before 128mph. So how do I calculate the proper shift speed? 6200 seems to be the sweet spot because above that the performance tapers.
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From: Ann Arbor, MI
OK, so the TPS issue is resolved and the PCM is using the WOT table.
Personally I calculate the MPH speed at 6000 rpm and set that into the shift tables - both the WOT speed table and the high end of the partial throttle tables. Then I set my WOT RPM to where I want to shift, typically between 6500 and 6900. This way I can quick change the shift RPM at the track without having to fiddle with the MPH tables.
There are various online calculators to determine the speed like this one:
http://www.bgsoflex.com/rpmmph.html
I just do it from logging.
Personally I calculate the MPH speed at 6000 rpm and set that into the shift tables - both the WOT speed table and the high end of the partial throttle tables. Then I set my WOT RPM to where I want to shift, typically between 6500 and 6900. This way I can quick change the shift RPM at the track without having to fiddle with the MPH tables.
There are various online calculators to determine the speed like this one:
http://www.bgsoflex.com/rpmmph.html
I just do it from logging.
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From: Harpers Ferry WV
cool deal, yea the tuner im working with now had me send some log files last night and we went back and forth for a few hours, got things looking alot better now. Car feels the best its felt since I finished the build
