Z32 What is correct MAF voltage reading

Discussion in 'Technical' started by madkiwi, Sep 5, 2020.

  1. madkiwi

    madkiwi New Member

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    So as part of dealing with my 93 TT constantly going into safety boost (with no codes) I am now communicating with Jim Wolf Technologies (ECU is one of theirs with a JWT POP-charger, standard JWT boost jets, producing 12 psi at wot).

    In my back and forth with them they were wondering about my MAF.

    4 years ago I checked the MAF, the shop manual says the signal wire should be at 0.8 volts with key on (engine not running) and 0.8 to 1.5 volts at idle with a warmed up engine.

    Mine was showing 0.44 volts with key on, 1.245 volts at idle. I purchased a used one on Ebay and swapped it out. Virtually the same readings. Both were cleaned with MAF cleaner, no change.

    Last weekend I tested a few things for JWT, including the signal at the ECU. My readings were 0.438 volts key on and 1.185 at idle. Identical readings probing the back of the ECU connector.

    The engineers at JWT are leaning towards "Your MAF sensor is bad". So either the manual has a misprint or everyone in Z-dom is driving around with a MAF that's out of spec, yet no-one else is reporting the safety mode gremlins I have experienced.

    Question is- what is the correct MAF voltage spec? Because if you search the internet (including 240sx forums which adapt Z32 MAFs for turbo conversions) you will see many people reporting key on voltages around 0.4 which is half of what the Service manual says it should be.

    I hate to just buy a new part (US$248) to R&R if the new one is going to have the same voltages and not solve the problem.

    If you have a working, no problem setup and you know what your MAF voltages are can you share them with me? If you have a factory MAF that actually has 0.8 volts (or thereabouts) with the key on please pipe in.

  2. zx299

    zx299 Well-Known Member

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    As I told you when you posted on TTnet ........ the voltage readings you are getting with the engine not running are normal.

    If your AFM was faulty, you would be going into limp mode (2500rpm limited), you should be looking at your detonation sensor or the antique JWT ecu you are using :rolleyes:
    MickW likes this.
  3. Harleynissan

    Harleynissan AussieSpeedingFines

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    Put the resistor across your det sensor.

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