APP Sensor

[jendougchanxan]

I have a '94 Chevy 2500 6.5 with the 5spd manual. Can the accelerator pedal position sensor affect shifting from one gear to another? The reason I ask is when accelerating fast and up shifting the engine will rev up even though my foot is off the accelerator pedal & not engage the next gear. I replaced the clutch & throwout bearing & the the flywheel stills look good but still experiencing the same problem.

 

[NVW]

Could be a bad PMD, does it do it while the APP is in a steady position while cruising?

BTW, welcome to TTS

 

[jendougchanxan]

Could be a bad PMD, does it do it while the APP is in a steady position while cruising?

BTW, welcome to TTS

Thanks for reply NVW. I replaced PMD and installed heat sync few years back.
It doesn't do it while cruising steady. Just when shifting to higher gear. Downshifting is fine.

 

[JayTheCPA]

A few years old PMD does not mean that it is still good a few years later

Another test is the 2K RPM cycle (http://www.thetruckstop.us/forum/threads/throttle-surprise.44359/#post-503301), however need to rule-out the PMD first (usually with another known good PMD).

 

[Will L.]

Can you post a video of it? Only doing it under hard acceleration has me questioning if it is the APP. I've seen a few fail out of hundreds of high mileage trucks, but they acted sketchy more noticeably under smooth acceleration. Have you removed and cleaned all your ground wires and mounting spots on the engine? This is a crucial thing to do for these rigs. A weak ground feeds wacky info back to the not so greatest electronics system, and odd things happen as a result.

When it comes to pmd, Having a spare pmd in the truck like a spare tire for diagnostics is the answer to many woes. A few hours have gotten a decade from one, then the next one lasts 3 months. Never plug one in that is not hooked to a heatsink. It can burn up in a few seconds. Always use the goop that comes with it for the same reason. The one time your 125 miles from the house and it goes bonkers on you is when you'll really appreciate having made the investment early.