throttle position sensor

[xenocath]

i have been searching for a procedure that explains how to set the throttle position sensor on the side of the ip however i cannot seem to locate a reference to it in the tms or haynes manuals either the diesel manual or the chevy truck manual. does anyone have a clue where to find the procedure? would greatly appreciate it.

 

[doghead]

Removal and replacement is covered in TM 9-2320-289-34, Chapter 3-46. 3 pages. Also in the -20, Chapter 3-21.1

BTW, I have new valves for sale in the classifieds( CUCV Vacuum Valves ), I include a copy of the TM pages, and a home made gage block, used to set it correctly.

Also, Warthog has posted a great thread on how to adjust the valve, here on SS. http://www.steelsoldiers.com/cucv/50568-cucv-throttle-vacuum-valve-adjustment.html

 

[xenocath]

ahh no wonder i could not find it. not sure i need a new one yet but it was the one thing i could not find any info on so therefore could not check its operation and its been bothering me. thank you for the info much appreciated.

 

[doghead]

Be sure to check or replace all your rubber vacuum hoses, if you are having inconsistent shifting. Also, after setting the vacuum valve, if your shifting is still inconsistent, you may need to replace your modulator valve, on the transmission.

These trucks should shift as smooth as any other normal vehicle.

 

[xenocath]

vacuum lines and modulator have been replaced as well as alll metal lines cleaned out with air pressure and carb cleaner truck hits shift points about right and it jerks very slightly so i think i have it dialed in. i was more just curious if adjustment of the vacuum valve (what i thought was tps) would change anything as far as get up and go. i have nobody near as far as i know to check my truck against as far as how they are supposed to run and operate normally. this is my first diesel truck so unsure exactly how its supposed to run and accelerate.

 

[mr.travo]

Would a bad TPS keep the transmission from downshifting as well? I can't get mine to downshift no matter what.

 

[TGP (IL)]

Downshifting is controlled by a electric switch mounted on the accelerator pedal bracket under the dash.
Controls a solenoid in the transmission on the valve body.
Make sure the single wire plug on the left side of the Trans, case above and behind the selector linkage is connected.
Can be pulled off easily.
Tom

 

[mr.travo]

I did a continuity check on the switch under the petal and got it to work. Wasn't solid tone at first but got it to start giving me a solid tone. I then checked and cleaned the kickdown plug on the side of the transmission. It will downshift now but not as good as my old CUCV at work did. It will downshift if you are below 33ish miles an hour and then again if you are under 45. It too bad. I imagine that the modulator needs adjustment, but I don't have the tools or know how. I DID notice that when I took off the rubber piece on the TPS and plug the lines straight in that the short rubber lone that goes to the hard line wasn't even hooked up so I imagine that's why it wasn't even downshifting. By having that one piece disconnected, do you think I caused any harm?

Also-- Where is the best place to get the Crankcase Depression Connectors at? One of mine is almost ripped in half, so I might as well change them both.

Thanks!

Travo

 

[engineman2]

My M1008 has a firm but consistent shift. It certainly isn't as smooth as my Chevrolet Tahoe. Doghead has the right idea with the vacuum lines. I replaced all of mine as well as the vacuum modulator when I changed the fluid. It certainly tightened up my shifts and helped with consistency. I live just South of you Xenocath if you need to compare, assuming mine is also correct.

 

[Warthog]

I know this is an old thread but here are some pictures on how to adjust the Throttle Vacuum Valve using the TM instructions.

http://www.steelsoldiers.com/cucv/50568-cucv-throttle-vacuum-valve-adjustment.html

The Throttle Vacuum Valve only effects the Upshifting and not the downshifting.

 

[engineman2]

ohh yeah I didn't even notice how old this was. lol

 

[ryan77]

Check your vacuum pump mine wouldnt shift out of 2nd! Turned out vac pump was weak!