Dead spot in TPS/FIPL

[60av8tor]

Adjusted my FIPL to about 1.15 idle - 3.8 WOT (as high as I can get) after new IP install. Now pulling code 62 (transmission 4/3 circuit fault) and won’t downshift out of 4th even with peddle to the floor. I noticed when sweeping the throttle from idle to WOT, I have a real quick blip around 2v where it goes to 0. Wondering if this may cause the 62 code and lack of downshift? Everything else is normal.The TPS is new as of last year, but I don’t remember seeing the blip/0v when I adjusted it then. Cheap part; may just replace it to trouble shoot.

Thanks guys!

 

[IDIBRONCO]

With my lack of transmission experience, it does sound like that may be the issue.

 

[60av8tor]

With my lack of transmission experience, it does sound like that may be the issue.

Thanks. I ordered a new one. It’s at least a relatively inexpensive troubleshooting step.

 

[DirtyWood]

Dead spot = New TPS time. Also make sure TPS ground is 0v and reference voltage is 5v. After much fiddling with the TPS I find that the recommended idle setting of 1.2 is really just about perfect in terms of holding a gear longer before shifting. Less likely problem to check for but I like to verify the throttle cable has not stretched and that I'm actually getting WOT with pedal to the floor

 

[60av8tor]

Dead spot = New TPS time. Also make sure TPS ground is 0v and reference voltage is 5v. After much fiddling with the TPS I find that the recommended idle setting of 1.2 is really just about perfect in terms of holding a gear longer before shifting. Less likely problem to check for but I like to verify the throttle cable has not stretched and that I'm actually getting WOT with pedal to the floor

Thanks for the info! Good info on the throttle cable, as I can only get 3.8v at WOT. I just posted this on another forum where someone posted a graph with the allowable voltage variation:

I wonder about only getting 3.8 at the top end. I understand about being below 5v, but I’ve read a lot that say idle is key, top end doesn’t really matter - get as much as you can. But that graph makes me wonder

 

[DirtyWood]

Thanks for the info! Good info on the throttle cable, as I can only get 3.8v at WOT. I just posted this on another forum where someone posted a graph with the allowable voltage variation:

I wonder about only getting 3.8 at the top end. I understand about being below 5v, but I’ve read a lot that say idle is key, top end doesn’t really matter - get as much as you can. But that graph makes me wonder

Some good info here, https://www.ford-trucks.com/forums/...-and-adjustment-diesel-applications-only.html

I agree that the idle setting is far more important than WOT voltage. The TPS setting is super sensitive. I currently have my TPS set to about 1.2-1.21, WOT is about 4.19, idle RPM at about 685, and I'm pretty happy with the shifting. I've also cleaned every transmission related connector and replaced every sensor except for the barometric pressure and swapped for an updated transmission control module specd for a '93-'94 turbo diesel.