1995 5.7 tbi hard shift

[Kylebg94]

Please Quote my post like this if you'd like me to respond as i dont get alerts and just happened to see a new reply here.

Scan the PCM and post the code(s) stored. Harsh 1-2 shift, which is what it sounds like you're describing, is usually valve body (tcc regulator valve) or broken accumulator piston spring in the 1-2 acc housing.

Ok, so I got two codes. 22 and 34. Throttle position sensor and map sensor

 

[NickTransmissions]

Ok, so I got two codes. 22 and 34. Throttle position sensor and map sensor

Makes sense, given the variability of your symptoms. Replace both with OEM equivalents once you confirm they are in fact bad and it's not a poor electrical connection or something else triggering those codes...Once you have new sensors in place, your harsh shifting symptoms should go away....The MAF influences the PCM's management of transmission internal line pressure so if it's over reporting or under reporting air flow, the AFM will also be off and consequently, the line pressure curve will also be out of phase. The TPS data stream is also used by the PCM to control the transmission, including playing a part in line rise response by the EPC to throttle input...same deal, if the TPS is reporting inaccurately to the PCM, well - garbage in, garbage out.

Let us know what happens once you have done the repairs.

 

[Kylebg94]

Makes sense, given the variability of your symptoms. Replace both with OEM equivalents once you confirm they are in fact bad and it's not a poor electrical connection or something else triggering those codes...Once you have new sensors in place, your harsh shifting symptoms should go away....The MAF influences the PCM's management of transmission internal line pressure so if it's over reporting or under reporting air flow, the AFM will also be off and consequently, the line pressure curve will also be out of phase. The TPS data stream is also used by the PCM to control the transmission, including playing a part in line rise response by the EPC to throttle input...same deal, if the TPS is reporting inaccurately to the PCM, well - garbage in, garbage out.

Let us know what happens once you have done the repairs.

So I replaced the tps sensor. And the old one was broken. However now the truck is idling high on startup. It did idle beforehand at around a 800 to 1k. Now it's 1500. I'm not sure why

 

[PlayingWithTBI]

Do you think it could be something simple like the maf sensor needing cleaning?

TBIs don't have a MAF sensor, they run strictly on Speed Density.

You really need to find a scanner or computer that can log and watch all data going to and from the PCM.

 

[sntrym]

Your MAP sensor may also be bad, or the vacuum line to it has a hole. Inspect and replace as needed. that will cause the high idle

 

[NickTransmissions]

So u replaced the tps sensor.

I replaced it or you (not "u") replaced it?

TBIs don't have a MAF sensor, they run strictly on Speed Density.

You really need to find a scanner or computer that can log and watch all data going to and from the PCM.

^^^^ This. Too many DYIers are working in the dark. Without a proper scan tool, that's essentially the position you're in.

Invest in a good scanner that can render live data to help you see what each of these sensors are actually doing given driver inputs/operation. There's several that have OBD-1 live data capabilities...Here's an example, you can research..

 

[Kylebg94]

This past week has been rough for me. I lost my great grandmother on Tuesday. The truck does have multiple issues. My car was hit by a deer not long ago as well. That's why I'm trying to get this truck right. So I'll have something to drive while my car is in the shop getting fixed. So if I'm all over the place or sat something wrong. It may be that I'm also trying to understand and learn while being under alot of stress right now.

 

[Kylebg94]

Your MAP sensor may also be bad, or the vacuum line to it has a hole. Inspect and replace as needed. that will cause the high idle

That was a typo. Yes the map sensor triggered code 34

 

[Kylebg94]

I replaced it or you (not "u") replaced it?


^^^^ This. Too many DYIers are working in the dark. Without a proper scan tool, that's essentially the position you're in.

Invest in a good scanner that can render live data to help you see what each of these sensors are actually doing given driver inputs/operation. There's several that have OBD-1 live data capabilities...Here's an example, you can research..

Yeah, I got it scanned at O'Reilly's. I

 

[Kylebg94]

Your MAP sensor may also be bad, or the vacuum line to it has a hole. Inspect and replace as needed. that will cause the high idle

The high idle went away after disconnecting the battery terminal for a few minutes after replacing the TPS. The idle seemed normal. I'm going to drive it for awhile and see how it does before I post anything else here.