Pro Mouse

iTrader: (15)

Ok ,I had my tuner calibrate my car for 85mm maf with no problems.Now I went back to my stock maf for a little bit.Now here is the thing ,I used to have a surging issue with the stock maf,None with the 85 mm maf.Now that I went back to my stock maf the surging problem is back.So I left my stock maf on and reflashed the pcm with the 85 maf tune ,(meaning I only changed the MAF Airflow vs. Output Frequency) and surge is now gone but yet with my stock maf How do I read the numbers with HP Tuners?I thought the Maf airflow vs.Output Frequency didnt come into effect until 1500 rpms What do the top numbers mean 1500 1625 1750 and so on up?I thought it was RPM's?If that was the case why is this effecting my Idle ,making it surge in park and drive ????Please help....

Another_User

It sounds like you are having a fueling problem. I have noticed similar things with my stock MAF after my latest round of tuning. Can you e-mail me some stock MAF and 85mm MAF logs and your BIN, and I will take a look at it and see if I can help. Send to someoneelse@adelphia.net. I can probably at least point you in the right direction. You should not be seeing a MAF frequency that low, so that should be RPMs. I am interested to see what you are seeing.

Pro Mouse

iTrader: (15)

Here are my MAF Frequency Tables the first is 85 MM maf
1.99 2.31 2.7 3.13 3.55 4.05 4.58 5.18 5.81 6.54 7.3 8.09 8.92 9.79 10.74 11.78 12.9 14.1 15.37 16.74 18.17 19.69 21.3 22.98 24.76 26.62 28.56 30.59 32.73 35 37.39 39.92 42.58 45.37 48.32 51.4 54.62 57.97 61.47 65.11 68.89 72.81 76.87 81.08 85.44 89.95 94.61 99.42 104.41 109.57 114.89 120.44 126.19 132.13 138.27 144.63 151.18 157.95 164.86 171.99 179.33 186.91 194.74 202.85 211.25 219.96 229.02 238.44 248.24 258.48 269.16 280.34 292.03 304.3 317.17 330.68 344.87 359.81 375.52 375.52 375.52 375.52 375.52 375.52 375.52

The second one is my Stock MAF Frequency Table
2.44 2.84 3.32 3.84 4.38 4.98 5.64 6.37 7.16 8.05 8.98 9.97 10.98 12.06 13.23 14.51 15.89 17.36 18.94 20.62 22.38 24.26 26.23 28.31 30.48 32.78 35.17 37.67 40.31 43.1 46.04 49.17 52.44 55.88 59.51 63.3 67.27 71.4 75.71 80.2 84.85 89.68 94.67 99.86 105.23 110.77 116.51 122.45 128.59 134.95 141.5 148.34 155.41 162.72 170.29 178.12 186.19 194.52 203.04 211.82 220.86 230.19 239.84 249.83 260.17 270.91 282.06 293.66 305.73 318.33 331.5 345.26 359.67 374.77 390.61 407.26 424.74 443.13 442.8 442.8 442.8 442.8 442.8 442.8 442.8
The rest of the pcm is the same,What does the number above these numbers mean?Thanks!

Another_User

Those tables are the amount of airflow (g/sec) @ x frequency in Hz. The numbers above those are the frequency. So with your stock MAF table, the first value is flowing 2.44 g/sec when the MAF frequency is 1500Hz. If your car is surging with the stock MAF, I bet it is running you way too rich. I don't suppose you put in bigger injectors or something? In reality, that 85mm MAF table should be running you way lean (I suppose it depends on how it was calibrated though, I would need to see some readings at idle to get an idea)

Pro Mouse

iTrader: (15)

I am new to the tuning this kind of stuff ,I am used to a timing light and a screw driver(LOL).Will it hurt performance if I use the 85mm scale with the stock maf?and How do I go about getting some readings?Thanks again

Another_User

You may be having problems also if you did not reset your computer and "un-learn" your trims that are saved in the PCM. You really need to log your fuel trims and see what works best. If it is an SLP MAF, I would start with a stock table or a 00 Holden Commodore table (what I currently work from). You can't do too much on these cars without some good logs to work from. Are you using just an 85mm MAF, or an SLP modified MAF?

jimmyblue

iTrader: (11)

Check the axis (Hz) and be sure you didn't copy a
short table into the MAF airflow vector. Later years
start at lower Hz and go out to higher. You need to
start at the proper frequency point which may not
be the leftmost.

Another_User

But doesn't that also depend on whether he has an SLP or not? Didn't they stick some silly resistor in there to fool the PCM?