PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

ADJUST MAF T ???

Old Aug 3, 2002 | 08:50 PM
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Default ADJUST MAF T ???

Need some help to just get things started.Had my car on the dyno.the air/fuel was 15.9 !! way high. readings went like this: 3900 rpm> 15.7, 4200 rpm > 15.9, 5000rpm > 14.4 and 6000 rpm > 13.8, 6500 rpm > 13.6........... need to get that 15.9 down to the low 12s is what i'm told.WHAT is a good start of an adjustment on an maft? bought one and have it on. but dont know what to start at. dont have an auto tap or ls1 edit to get any readings. so was wondering what would be a good baseline adjust. to start out to set the maf base and the maf wot at??? i belive the 4 switches stay off, and right now the base and wot is at "0". seen some other posts on this subject, but dont have enough knowledge about it to get a start adjust.so it will run pretty good. any help??? thanks lots...... Terry.
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Old Aug 3, 2002 | 09:34 PM
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Default Re: ADJUST MAF T ???

The easiest thing is to send back the superchips for a reprogram <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> That A/F is way too high.
On another note I would adjust base setting to 20 % rich and take it from there.
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Old Aug 3, 2002 | 09:50 PM
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Default Re: ADJUST MAF T ???

After i had my long tubes installed, i contacted super chips..... they wanted an additional 275.00 to 300 $$$$ to reprogram the "chip" said if i didnt do it i would have problems with it running right with the addition of the long tube headers. so i UN PROGRAMED THE super chip, put it back to stock and the readings from my dyon is what you see. SO.... YOU ARE SUGGESTING to go with the base at 20% rich and leave the wot at 0 at this time?? sure can give it a try. thanks.
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Old Aug 3, 2002 | 10:01 PM
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Default Re: ADJUST MAF T ???

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by TERRY:
<strong>After i had my long tubes installed, i contacted super chips..... they wanted an additional 275.00 to 300 $$$$ to reprogram the "chip" said if i didnt do it i would have problems with it running right with the addition of the long tube headers. so i UN PROGRAMED THE super chip, put it back to stock and the readings from my dyon is what you see. SO.... YOU ARE SUGGESTING to go with the base at 20% rich and leave the wot at 0 at this time?? sure can give it a try. thanks.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">If you have to bias the MAF signal to -20,
that says your injectors are too small to handle spiking during WOT, makes PCM believe there is a much higher engine load, thus less timing and costs you torque, if auto trannie, lower line pressure and could cold misfire during certain fuel trim cells where it was closer to 0 LTFTs before making that much of a MAF signal change.
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Old Aug 3, 2002 | 10:21 PM
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Default Re: ADJUST MAF T ???

JOHN, Yes its an a4 trannie. i have the hhpIII BUT ONLY ADJUSTED THE TRANNIE % TO 75% FOR FIRMNESS........ did not use the power programmer part as i will not work well with a ported/polished throttle body. dont know if this helps, the sae #s for my car is 321.9 for power and 330.7 for torque. suppose to pich up around 8-10 hp from getting the air/fuel adjust correct, plus will just preform better. so do you agree that a good start would be to start the base at 20% rich?? terry.
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Old Aug 3, 2002 | 10:46 PM
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Default Re: ADJUST MAF T ???

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by TERRY:
<strong>JOHN, Yes its an a4 trannie. i have the hhpIII BUT ONLY ADJUSTED THE TRANNIE % TO 75% FOR FIRMNESS........ did not use the power programmer part as i will not work well with a ported/polished throttle body. dont know if this helps, the sae #s for my car is 321.9 for power and 330.7 for torque. suppose to pich up around 8-10 hp from getting the air/fuel adjust correct, plus will just preform better. so do you agree that a good start would be to start the base at 20% rich?? terry.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Terry to get the best results using a MAFT you need to do some work using a decent PCM scanner and see really how rich or lean the powertrain is across the RPM/engine load range.

Also with scanner record the injector pulse width for both heads. If you see pulse widths near or above 18 mSecs then your injectors are being driven over the recommended 80% duty cycle and and forcing the PCM ( via lying to PCM via a high change with MAFT) to go so much richer will not give you the best overall tune for part throttle and PE (WOT).

The lower ( less) air the PCM thinks ( forcing richer) there is, the less torque and line pressure.

So if your in the game you gotta do the PCM recording and analyze what truely is going on for the MAKEUP of YOUR powertrain and not what was best for someone elses powertrain for a simple thing as they being a sealevel and you at 3,000 ft means their adjustments are not best for your's

Sorry I do not trust chassie dyno results esp for AFR for some 02 sitting in a muffler tip is not good enough to get true AFR values so use the scanner and judge the part throttle AFR, dial it in ( if it is not overdriving present injectors) and only then work on PE conditions.
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Old Aug 4, 2002 | 05:02 AM
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Default Re: ADJUST MAF T ???

JOHN,,,,,TEAMZR1, YOU ARE TOOOOOO COOL! NOW I understand what you are talking about <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> THANKS so much for taking the time and explaining something to ME!!!!Yes, you could say "I'M IN THE GAME", but most importantly, Iwant my car to preform at its best weather i'm at the track or just driven around. one last question if you please. what type of "scanner" do you recommend i get tso i can get the neded "readings" for adjustment???????? THANKS SO MUCH, Terry.
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