TPS and Tranny cant get along under load!

Pinger said:

From an earlier post on this forum:

''
Shift timing and converter lockup at part-throttle is purely a function of TPS vs MPH for a given gear except in kickdown mode (WOT) where engine rpm is also referenced. Temperature also has a minor effect on shift points. Load calculation and torque management control the line pressure and is heavily affected by the MAP and MAF.''

Could you have a bad speed sensor? Which gauge(s) is bouncing - speedo?

edit PS. Should maybe have mentioned the above is from a conversation about 4L 80E shifting.

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Funny you mention the speed sensor. When I went to buy the truck the first time, he told me the speed sensor went out... so, he replaced it and then I picked it up later. My speedo is running 10mph faster than it should be... its my speedo and fuel gauge that get weird... RPM is fine, oil pressure and temp arent hooked up, I have externals for those.

Because the speedo is running fast and that is one of the gauges that is acting weird, could this be causing the issue? He put a new one in but, would the speed sensor cause the issue I am having? I never drove it before this sensor was put in.

no more tranny experts out there?

did you test the tps?

How do you do that? its a B&M TPS https://www.holley.com/products/drivetrain/transmission_controller/parts/120002

I have adjusted it tighter/looser at the carb and all it did was jack up my shift points. I also found online how to do it with a voltmeter... will do that today.

thegawd said:

did you test the tps?

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With Key on (not started)
Multimeter at 20V

Red wire: 5.5V
Yellow: .32 at idle, 3.95 at WOT

Can I adjust this? It seems like it's just set low compared to the specs it's supposed to be. I can see the TPS has 2 screws where I can turn it a little both ways.

your in over my head but I'm sure your on track.

I wish I could help more, maybe the truck needs a tune to understand the data? I dont know....

Al

thegawd said:

your in over my head but I'm sure your on track.

I wish I could help more, maybe the truck needs a tune to understand the data? I dont know....

Al

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Well ****.. LOL I am in over my knowledge level on this too... das why I am asking! LOL

I just turned the TPS to get .95 at idle but, when at WOT its 12.9 now... which I think is way too high... the averages I have seen are 1.0ish - 9ish.... it does bounce around when I am not messing with it... which makes me wonder if its the TPS that's bad.


Here is my wiring

TPS Side Red - connected to Blue
TPS Side Yellow - connected to greyish white
TPS Side Black - connected to black

TPS on my Vortec gives 0.6V at idle and 5-5.5V WOT and I think that is typical of most TPSs.

Do a throttle swing with your voltmeter. It should run smoothly from around .5v to 5.5v. If it hiccups during the swing, it's bad.

Erik the Awful said:

Do a throttle swing with your voltmeter. It should run smoothly from around .5v to 5.5v. If it hiccups during the swing, it's bad.

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I did that and she swings pretty smooth. Just the numbers are off based on your readings ... my peak at WOT is in the 3s. when I turn it to adjust, it gets all funky...

My next issue with replacing it is.. it comes in a B&M kit.... called Jegs to see if they stock a replacement and of course they tell me I have to call B&M. They don't have P/N for a replacement that will work with the bracketry... UGH!