TPS Voltage

[Tonyrodz]

He said he just drained the converter. No flushing.

 

[sefiro]

Hhmm, convertor can't be drained without some disassembly. He may have drained it during the rebuild.

Tps is a potentiometer - variable resistor. You can ohm to verify the variability , but do it with pigtail in various positions. The rebuilder probably looked at the tps thinking (per gm tsb) that since the pcm uses tps, rpm and engine speed to identify shift points, the tsp signal or dirty butterfly would confuse the shift points. However, the transmission should enter 1st gear and have full tanny/engine power there as the shift points would only affect getting into 2,3,,,,. Try putting the gear shift into 1 only to see if power result changes.

The power loss could be
1) drive train impeding (brakes, tranny, tire friction)
2) engine work load (ac, Hill climb)
3) bad pcm control due to bad tune or signal confusion.

1) since the tran was rebuilt, valve, solonoid, servo problems could cause bands to grab too early.
2) not much to search here
3) make sure no codes are set. Get a decent scanner/reader and monitor the various sensors 02, tps, rpm,temps etc to see if any if these are out of whack.

Sent from my XT1053 using Tapatalk

 

[Tonyrodz]

Hhmm, convertor can't be drained without some disassembly. He may have drained it during the rebuild.

Tps is a potentiometer - variable resistor. You can ohm to verify the variability , but do it with pigtail in various positions. The rebuilder probably looked at the tps thinking (per gm tsb) that since the pcm uses tps, rpm and engine speed to identify shift points, the tsp signal or dirty butterfly would confuse the shift points. However, the transmission should enter 1st gear and have full tanny/engine power there as the shift points would only affect getting into 2,3,,,,. Try putting the gear shift into 1 only to see if power result changes.

The power loss could be
1) drive train impeding (brakes, tranny, tire friction)
2) engine work load (ac, Hill climb)
3) bad pcm control due to bad tune or signal confusion.

1) since the tran was rebuilt, valve, solonoid, servo problems could cause bands to grab too early.
2) not much to search here
3) make sure no codes are set. Get a decent scanner/reader and monitor the various sensors 02, tps, rpm,temps etc to see if any if these are out of whack.

Sent from my XT1053 using Tapatalk

I think #3 might be my issue here. I'm thinking it was drained also during the trans rebuild. This guy has rebuilt the trans in my work van and it shifts amazingly crisp. It actually leaps when I'm on it, so I'm confident he knows what he's doing. I've put it in gear with my foot on the brake while pressing the gas while holding my phone to get a video of it. It jumped so hard that my phone went flying, so that felt good. I'm going to try what you said, leave it in 1St and hit it. I'm guessing it'll wind out but keep pulling. Now it shifts at around 5,000 or so, which it was tuned to do after the can, engine work and tune. Thx for your input.