jonlabree Posted April 19, 2008 Share Posted April 19, 2008 Stupid question #1. Which wire at the mass air flow sensor on the throttle body can you get the output voltage reading? Link to comment Share on other sites More sharing options...
jonlabree Posted April 19, 2008 Author Share Posted April 19, 2008 Bump Please?? Link to comment Share on other sites More sharing options...
jonlabree Posted April 20, 2008 Author Share Posted April 20, 2008 NO one knows????? Link to comment Share on other sites More sharing options...
D-a-n-i-e-l Posted April 20, 2008 Share Posted April 20, 2008 The yellow or pin "A" is the output signal to the ECM. Black or "C" is ground. And pink/black or "B" is ACC. Link to comment Share on other sites More sharing options...
jonlabree Posted April 20, 2008 Author Share Posted April 20, 2008 Thanks Daniel. I wasn't sure about it.I was supprised that no one else knew which one it was.For a repy, next I was going to ask with multiple choiceA, B, or C.Thanks againJon... Link to comment Share on other sites More sharing options...
2seater Posted April 21, 2008 Share Posted April 21, 2008 The MAF output to the ECM is frequency based. The maximum frequency is 10.4kHz, or 170 grams per second. I have a chart of the frequencies vs airflow around somewhere. Link to comment Share on other sites More sharing options...
2seater Posted April 21, 2008 Share Posted April 21, 2008 I used a Radio Shack VOM with frequency capabilty to test MAF's on my flowbench. This is the chart I mentioned.Hal, here is a list of Hitachi MAF sensor flow rates GM assigned the MAF sensor output frequency in a stock 3800 vin C chip...MAF Vs. Output Frequency Table 1 kHz gm/sec 2.00 3.19 2.13 3.53 2.26 3.94 2.39 4.38 2.52 4.81 2.66 5.31 2.79 5.88 2.92 6.41 3.05 6.97 MAF Vs. Output Frequency Table 2 kHz gm/sec 3.05 7.44 3.18 8.06 3.31 8.81 3.44 9.56 3.58 10.31 3.71 11.31 3.83 12.50 3.97 13.69 4.10 14.88 MAF Vs. Output Frequency Table 3 kHz gm/sec 4.10 13.9 4.23 15.1 4.36 16.5 4.49 17.9 4.63 19.3 4.76 20.8 4.89 22.4 5.02 23.9 5.15 25.4 MAF Vs. Output Frequency Table 4 kHz gm/sec 5.15 25.43 5.28 27.07 5.41 28.55 5.54 30.19 5.68 32.16 5.81 34.13 5.94 36.09 6.07 38.23 6.20 40.20 MAF Vs. Output Frequency Table 5 kHz gm/sec. 6.20 41.00 6.33 43.25 6.46 45.75 6.59 48.25 6.73 50.75 6.86 53.75 6.99 56.50 7.12 59.50 7.25 62.75 MAF Vs. Output Frequency Table 6 kHz gm/sec 7.25 62.5 7.38 65.8 7.51 69.4 7.64 72.7 7.78 76.3 7.91 79.6 8.04 83.2 8.17 87.2 8.30 91.2 MAF Vs. Output Frequency Table 7 kHz gm/sec 8.30 91.2 8.43 95.2 8.56 99.3 8.69 103.3 8.83 107.8 8.96 112.4 9.09 117.4 9.22 121.9 9.35 127.0 MAF Vs. Output Frequency Table 8 kHz gm/sec 9.35 126.3 9.48 131.0 9.61 136.4 9.74 141.8 9.88 147.1 10.00 153.2 10.14 158.6 10.27 164.6 10.40 170.0 Link to comment Share on other sites More sharing options...
D-a-n-i-e-l Posted April 21, 2008 Share Posted April 21, 2008 That is great info. Do yoiu do your own tuning? Link to comment Share on other sites More sharing options...
2seater Posted April 22, 2008 Share Posted April 22, 2008 The information came from Ryan of GM Tuners. The remote MAF's from the 3400 (3") and the 3.5" LT1 MAF's use the same frequency range so our ECM can read the full range, although the air flow at the same frequency is different, of course. I ran a comparison between the 3" MAF and the stock Hitachi MAF from the vin C for Ryan and the flow rate is almost exactly 1.5:1, actually about 1.52 as much air flow, which is a good match for most moderately boosted stock engines. Link to comment Share on other sites More sharing options...
D-a-n-i-e-l Posted April 22, 2008 Share Posted April 22, 2008 That is great info and I may use it when I do my final tune Link to comment Share on other sites More sharing options...
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