86carbPU

Brother's got 1988 22RE w/new long block & trying to get up & running after install w/original 200k mile EFI. Decided to troubleshoot TPS & this is what I got:

VTA-E2 - registered 0.6k closed & 3.9k open
IDL-E2 - didn't get anything in return w/either feeler gauge
Vcc-E2 - registerd 0.5k

These are the specs I was shooting for as copied from 1988 Factory Service Manual:

0mm: VTA-E2 0.2-0.8k
0.57mm: IDL-E2 less than 2.3K
0.85mm: IDL-E2 infinity
Throttle Fully Open: VTA-E2 3.3-10k
n/a: Vcc-E2 3-7k

*0.57mm: 0.533mm + 0.038mm = 0.571mm
*0.85mm: 0.584mm + 0.229mm + 0.038mm = 0.851mm


After removing the throttle body from the intake chamber so that I could better insert my feeler gauge, I then proceeded to loosen the mounting screws & rotated the TPS body both ways to get any kind of reading between IDL & E2, but nothing.

I tested it again after adjusting the stop screw by loosening the nut, backing off the screw, then turning the screw in to barely contact the lever & finally turning the screw in again a little less than 1/4 turn past initial contact so that the throttle plate wouldn't stick.

It seems to me that the IDL-E2 circuit is shot. Does anyone know if this is a common occurance? Could there be some kind of human error on my part? Hopefully someone can take advantage of the posted TPS(Throttle Posistion Sensor) specs for 1988 22RE.

Believe it or not I found an old TPS in the glove box. I mounted it up & it wouldn't read anything between IDL & E2 either. I wonder if the computer or circuits in between somehow shorted out the IDL-E2 circuit inside the TPS? Maybe I'm just not managing the feeler gauge properly?

dubbsbetty

iTrader: (2)

Sounds like you've done you homework! If you don't have access to a vantage tool or some kind of diagnostic with a scope pattern, trace the wires back to the PCM and look for any irregularities from the TPS signal and ground to the PCM connections. Make sure the connections to the PCM are solid and like you said, not shorted, loose, or damaged. Check the wiring diagram for what could possibly be in connection with the two, usually its the connector terminals, the wiring in between or the units themselves. If your readings are higher than spec on VTA and Vcc-E2 but good on the IDL-E2, I'd say maybe the sensor itself? It's possible that the adjusting screws might be worn down enough that even though they make contact, maybe not providing the right length. Not trying to shotgun solutions here, just a green tech myself, hope any of this helps!

86carbPU

Bought new TPS & tried it out. Showed up the same way. No reading between IDL-E2. Must be doing something wrong w/feeler gauge.

Decided to test the old TPS of the throttle body & rotate the butterfly spindle by hand w/ohmmeter probes connected between IDL-E2. Deflection occured at what seemed a random point along the rotation. It shot up & dropped out very quickly; very sensitive. The IDl-E2 circuit must be OK & just not adjusted properly while mounted to throttle body. Must be the feeler gauge I'm using or something I'm not aware of.

Continued troubleshooting. Couldn't find any shorts in the wiring back to the c
omputer but my search was limited to the harness insulation & fenders.