1991 FJ80 3FE TPS Readings, Troubleshooting

Joined
Nov 13, 2017
Messages
39
Location
CA Desert
Got a 41 code the other day on my '91 along with rough running/loss of power followed by sudden return of power. Pulled TB to clean (fair amount of carbon build up), and TPS to test. Set up TPS according to manual (was about a hair off at 0.93mm between IDL-E2 - set, tightened screws, and marked), and re-checked my work. All readings in spec except VTA - E2 at WOT. Manual calls for 3.5-10.3 kOHM. I read 3.2-3.3 kOHM. Is that enough variance to cause concern?

What do the three letter acronyms stand for? I assume IDL=idle. What about VTA, VC, and E2? Vehicle electronics and measuring resistance blows my mind. I have no idea what exactly I'm measuring - just what numbers to look for.

While I was in there, I also replaced the VC gasket, VC stud seals ("doughnuts" on top of VC), and PCV valve/seal. All the people here who say the VC gasket is easy either know some sort of black magic wizardry to get it on, or are liars. That thing was a bear to get on. Took me longer to replace that than anything else.
 

TrickyT

Hate that mud...
SILVER Star
 
Joined
Apr 1, 2006
Messages
1,488
Location
Mill Valley, CA
Code 41 is an open or short in the TPS signal. Your TPS readings seem within normal limits, so maybe it's a corroded or intermittent contact in either the TPS connector or the ECU connector or perhaps a frayed or broken wire in the harness. Reset the code and see if it comes back again. There's also a section in the FSM that describes testing for voltage on the back side of the ECU connectors. So if the code comes back you could try that, since this will test not only the TPS but also the harness and connectors.
 
Joined
Nov 13, 2017
Messages
39
Location
CA Desert
Code 41 is an open or short in the TPS signal. Your TPS readings seem within normal limits, so maybe it's a corroded or intermittent contact in either the TPS connector or the ECU connector or perhaps a frayed or broken wire in the harness. Reset the code and see if it comes back again. There's also a section in the FSM that describes testing for voltage on the back side of the ECU connectors. So if the code comes back you could try that, since this will test not only the TPS but also the harness and connectors.
Thanks Tom. I've got a CEL again (going to check in a bit what the code is - likely 71 due to de-smog). I'm going to chase wires down this weekend to check for frays/breaks, too. Will report back with results. So far, I've only experienced the symptoms one time very briefly since adjusting the TPS, leading me to believe that's not the issue like I thought/hoped. Oh the joys of owning a 27-year-old truck.
 
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