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Thread: are all TPS same value?

  1. #1
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    are all TPS same value?

    have a Lingenfelter super ram, uses a tps that is non adjustable, in that the mount holes are not slotted,
    it is similar to most in the late 80's ( 3 wire connector)
    I tried using a brand new TPS from a buick Grand National, car wouldn't even start,
    they ohm out similar to orig,
    I ended up using orig TPS and only used one screw to adjust/ hold it, to get the value I needed.
    anyone have knowledge of these?

  2. #2
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    No, not all TPS are created equal. Generally the signal going to the TPS is the same (I've only ever seen cars send a 5V signal to TPS, though it's entirely possible there are older cars that use 12V), but the signal coming out is different.

    As an example, on the Chrysler PT Cruiser, the TPS 0% outputs about 0.7V, and 100% outputs about 3.77V. If you use a scan tool that assumes TPS is 0V~5V, this will end up reading on 14%~75%. It's not actually reading 14%~75%, because the computer expects 0.7V at 0% TPS and 3.77V at 100% TPS, it's just the scan tool misinterpreting it.

    So what's important is the range of values that your particular ECM/PCM expects for 0% and 100% TPS. These can usually be found in the Factory Service Manual in the diagnostic section for TPS error messages. Again, as an example, for the 1995 Corvette the acceptable range for 0% is 0.3V~0.9V (and automatically calibrates at key-on-engine-off), and 100% is up to 5V (full range). This is wildly different from the system on the PT Cruiser, and indeed, each system tends to be unique.

    So yeah, first find out what range of values your ECM wants, then you can try to match a TPS accordingly.
    1990 Corvette (Manual)
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  3. #3
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    THX,
    ecm is 90-92 firebird. #1227730
    so will attach scanner and see what it gives me for numbers,
    was looking thru SLP papers, found # for tps there, gm # 17111606, slp # 23042

    so will go from there,

  4. #4
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    Pretty easy to back probe connector with key on to check the output voltage value. Its also possible the pin assignments could be different. Being GM that's not usually the case but try comparing the two respective applications wiring diagrams.
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  5. #5
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    All the GM ones work pretty similar. I think they are all the same resistance. The closed and open throttle output voltages would vary a bit depending on the throttle body they are attached to.

    I don't think the '730 PCM needs an adjustable TPS. It will learn the closed voltage.

  6. #6
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    well, adjusting orig tps, makes a huge difference in drivability, previously, had hard time starting from a stop, car would nose over, or rev ,
    setting tps to listed value, made the car 100X easier to drive,
    also cruise previously was unstable/erratic, would not hold steady rpm,
    now more normal and steady rpm,
    I did order the listed tps sensor, it'll be here next week, so will see what difference it makes,
    thx to all who offered advice ,
    my next task is to check/set the timing, used to be a wire you disconnected (not sure of color)
    anyone remember?

  7. #7
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    On the 7730 ECM it is the "EST Bypass" connector you disconnect. If my sources are correct, the wire should be Tan/Black. This removes ECM timing advance so you can set the initial base timing advance.
    1990 Corvette (Manual)
    1994 Corvette (Automatic)
    1995 Corvette (Manual)

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