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Bad TPS???

2935 Views 25 Replies 8 Participants Last post by  cheappower82
Well further testing shows that the TPS is cosntatntly putting out 5 volts. I do not understand why but I just assume its broken. At leist I hope. Im hoping thats its not doing that because of some type of constant ground somewhere or something. Im going to try and replace it and if that doesnt work then Ill now I have to chase some damn wires down. Thanks much...

PS- I wonder what this is doing for my fuel trims...consdiering the EFI runs the injectors and timing according to TPS, and the AFM. Although the AFM is functioning fine I wonder if the TPS is making things screwy. If anyone knows of anythign that this might be please chime in. THanks,


Austin
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Well if you still want to keep the S-AFCII, the hardest things to come by is the harness and the ECU ('85).

The throttlebody and TPS that came with my 6M-GE will work. So if you can locate the '85 harness and ECU, I'm sure that someone will sell you their 6M TB and TPS cheap (I may have extras laying around in storage).
if you have an on/off type of TPS, you can add a MAP sensor from just about any car and use the vac to zero reading as the TPS input.. this way you can have varying conditions instead of off/on.
How similiar is the MAP readings compared to the TPS readings. Is it close enough, to use to tune easily?

Also I have an 83' Celica with the old school analog ecu system from what I understand. It is a really simple ECU, but I just wanted to make sure the SAFC II would still work with it. Since the ecu still tells the injectors how much and when to run. Would the SAFC II still work for me?
Any clues or ideas guys :lol:

Ohh yea how would you get the MAP sensor to work with boost pressure, read a little about probs and how to get it to work but still not sure. ANy help is appreciated :)
I am trying to get my head around this TPS problem for the SAFC, is the main problem for the older ones, 82's, 83's that the voltage is too high off the TPS?
Couldn't you just make a voltage divider to drop the voltage into a range that the SAFC understands? As the voltage still varies right?
SlimFastSupra said:
if you have an on/off type of TPS, you can add a MAP sensor from just about any car and use the vac to zero reading as the TPS input.. this way you can have varying conditions instead of off/on.
What he means about the on/off TPS is this: 85 and newer uses a variable voltage (true throttle position) tensiometer type TPS. As you depress the gas pedal, the sensor sends a different voltage per position (prorated). Some TPS's go from low to high voltage (0-5V), and some decrease with TP (5-0V).

The 84 and older (square TPS) act as an on/off switch. As the pedal is depressed, the TPS goes from no voltage to max (usually 5V).

That's the way it was explained to me.
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