Are these MAF readings messed up???
04-27-2010, 10:30 AM
#1
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Are these MAF readings messed up??? I got this car tuned recently and was trying to set the shift points where I want them.... I noticed what looks strange with the MAF numbers in my Data Log. Is this normal or is something messed up on my car????
The MAF readings below are are in 2nd gear in an A4 6.0L with EPS cam and 85 mm MAF. Obviously they go up as rpm goes up, but is something wrong that is causing them to roll up and down as rpm increases???? I would think that they should continue to just go up and never go down as RPM increases???? These values are from 5000 rpm to 6243.
32.77 5000RPM
35.68
35.7
38.96
37.49
34.83
38.76
40.78
39.23
36.35
36.35
42.79
36.06
42.79
38.33
38.81
38.09
43.55
44.42 6243 rpm
thank you!
The MAF readings below are are in 2nd gear in an A4 6.0L with EPS cam and 85 mm MAF. Obviously they go up as rpm goes up, but is something wrong that is causing them to roll up and down as rpm increases???? I would think that they should continue to just go up and never go down as RPM increases???? These values are from 5000 rpm to 6243.
32.77 5000RPM
35.68
35.7
38.96
37.49
34.83
38.76
40.78
39.23
36.35
36.35
42.79
36.06
42.79
38.33
38.81
38.09
43.55
44.42 6243 rpm
thank you!
04-27-2010, 11:06 AM
#3
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I don't have the tune file on my work lap top, so I will have to post later. I have the log in excell. I turned it into a text file and attached. I deleted most of the extra junk from the file and left the couple WOT pulls.
THere is some kind of KR issue when i firts get on it. I have to roll into the throttle so I don't blast off the tires. I also noticed that it is now in the low oct table...... Not sure what kicks it in there, but I am sure it has something to do with the initial huge amount of retard that I see. I need to figure out if it is in the tune or mechanical....... The car still runs strong even with this low *** timing.
THere is some kind of KR issue when i firts get on it. I have to roll into the throttle so I don't blast off the tires. I also noticed that it is now in the low oct table...... Not sure what kicks it in there, but I am sure it has something to do with the initial huge amount of retard that I see. I need to figure out if it is in the tune or mechanical....... The car still runs strong even with this low *** timing.
04-27-2010, 02:00 PM
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Would take quite a while to make that table make sense other than you've clearly got no problem hammering it. If you don't trust the equipment enough that you need to ask us, I sure wouldn't mash the gas as you do.
04-27-2010, 02:39 PM
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Nothing is falling appart mechanically and the KR issues were not present during the dyno tune. However, the same loads were also not present. There is no audible noise. I will have to log my GTO and see what the MAF looks like on it to compare. I have only driven it 15 miles since the tune, so it is not like it has gotten dirty or things have really changed. The MAF question came up as a result of me seeing it when looking at my logs trying to set the shift points.
04-27-2010, 03:40 PM
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What is your opinion on the KR??? I am going to do some messing around with pulling timing from the tables and see if it goes away to try and identify real or false KR. I will also look at the knock learn and see what it says.
thanks for your help. I will try to post my tune tonight.
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04-28-2010, 08:23 AM
#8
Similar problem here I am having a similar issue that you are having with your tune. I had my car dyno in Dec (in stock trim). Came up very lean 16 - 17 : 1 A/F ratio. Could do any hard pulls beyond 4500rpm - just too damn lean. I sent the ECU out for a mail order tune and the tuner said that I had a stock tune present. So my lean condition was probably caused by a faulty MAF (working , but reading inncorrectly). I picked up a used one and I'm not sure that my problem is resolved. It maybe bad as well. I will keep you posted if I find a solution.
Later,
Later,
04-28-2010, 09:00 AM
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I have a known good one that you can try if you want. Your other mods could have leaned it out a little, but not that much... Do you have stock injectors? With 90k on the pump, how is your fuel pressure?
I spoke to one of my friends and he said that the rolling MAF numbers are normal. I am still planning to log my GTO and compare. I need to mess with the shift points on it as well anyway.
I spoke to one of my friends and he said that the rolling MAF numbers are normal. I am still planning to log my GTO and compare. I need to mess with the shift points on it as well anyway.
04-28-2010, 12:33 PM
#12
Well, let me just clarify so you don't get too stressed. You can get fluctuations. MAF signal does like to bounce up and down a little depending on the pre-MAF air tract. In between shifts it will of course dip as the rpm's drop. I just think you need more or better tuning. Its not as bad as you think it is.
