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  • #31
    See page 165 for resistance checking on the knock sensor. Check in from the white wire on ecu pin 27 with the ecu unplugged ( measure on the harness side of the connector) vs directly at the knock sensor. This will check the wiring and the sensor together. This may increase the odds of misdiagnoses, but eliminates the dissambly required.

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    • #32
      Hm. I'm gunna go through and re do my readings when it's warmer. I'm not sure what's up. But my harness is un touched


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      • #33
        Haven't gotten to resistance checking but I did check voltage. White wire was at 12 volts. Black was at 12.8 volts. Black/white was at 14 volts. All tests were performed on a warm motor. Engine running. Black lead on the negative terminal. Cleaned the maf with maf cleaner. Same results.


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        • #34
          So I did some digging around. Ran a new ground for the maf and now the white wire runs about 4 volts now. Grounds resistance is about .1-.5


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          • #35
            From looking at the FSM the only thing on the MAF that should be grounded directly is the shielding on the harness. Which wire did you take to ground?

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            • #36
              The black ground wire. Looked around on google and some people have had that ground being the problem.


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              • #37
                I don't think that's a good idea. If that's what it takes to fix it, you still ave a problem. Unless you (or anyone else around here) understand the internal architecture of your ECU, grounding that black wire is like applying a risky bandaid to the problem. You could be bypassing internal circuits. I.E. the ECU may measure voltage drop on the negative leg of the MAF to determine fuel metering. IF that was how the ECU was designed, then grounding that leg would drop the ECU's "seen" voltage drop to near zero.

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                • #38
                  Sensor ground must go back to the ECU.

                  I think you might have fried something by putting your meter from a 12V+ leg across the MAF and potentially the ECU circuit.

                  Isn't the MAF on a 5V circuit? I know its max output is 5V.
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                  • #39
                    Power feed to the maf is 12v

                    Output signal is 5v max

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                    • #40
                      Hope I didn't fry anything. I'll hook it back up and see where it goes from there I guess.


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                      • #41
                        Is the MAF output signal 5V from ground or 5V across the MAF high and low terminals? The 12.8V on one pin and 12V on the other would leave 0.8V across the resistive element of the MAF. Which is in the ballpark of correct.

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                        • #42
                          If you fried the ECU, odds are that white wire would have gone to ~12V or 0V. Either shorting or opening the MAF's circuit. 4V would indicate that it did not cause catastrophic failure, but without seeing the ECU's schematics it would be hard to tell for sure.

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                          • #43
                            Originally posted by josh_s13 View Post
                            Is the MAF output signal 5V from ground or 5V across the MAF high and low terminals? The 12.8V on one pin and 12V on the other would leave 0.8V across the resistive element of the MAF. Which is in the ballpark of correct.

                            That's correct but why would black/white be reading battery voltage? 14v with alternator running. Is that the power wire?


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                            • #44
                              The black and white wire comes from a fuse panel through a relay controlled by ECCS. Yes, It is your power wire.

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                              • #45
                                Black is ground. But I'm getting crazy resistance from battery ground to it.


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