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85 mm MAF question!!!

Old 12-24-2007, 04:22 PM
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Default 85 mm MAF question!!!

Does anyone know how I can check the calibration table on a MAF sensor without using tuning software like LS1 Edit??

I am currently running an 85 mm MAF corvette sensor (p/n 25168491) that came with the vehicle when I bought it. I don't know if this sensor was calibrated to run on an LS1 but judging by my LTFT (+11)i believe that it was not. Since the computer keeps on adding fuel(lean condition) even after a header installation.

I had a friend lend me his MAF from his camaro and I notice a considerable improvement on my fuel trims (+3.91). I don't want to have to buy a new MAF is there anything else that I could do to find out what calibration table the MAF currently has???

If I am not mistaken this is a sensor you can buy with the proper calibration from Pace Performance, I will give them a call after the holidays to see if it is theirs.
Old 12-24-2007, 05:38 PM
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Usually adding the 85mm maf will make your vehicle run rich if not tuned. You really need to find someone with efi live to see if your tune is stock. There might somethin else going on here. Are there any codes being throw?
Old 12-24-2007, 06:06 PM
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If it is a stock Delphi 85mm on a stock tune F-body
you will have +25 LTFTs and a SES light.

Two options are, either it's tuned, or this "Corvette"
MAF is really a SLP MAF and the lean fuel would be a
likely result esp. with the " '98 - '00 " version they
sell. A SLP MAF will have a screen (if not molested
after the fact) and it will have a resistor with a heat-
shrink tubing "jacket" which you can see from the
backside. See pic:

Have a look, if it has this resistor then one option is
to swap it out for a higher value and see how that
does. I have played with this before I had tuning tools
and it is effective. 2.4K (red/yellow/red) is used on the
MAFs that "lean you out for more power" (right), 2.7K
(red/violet/red) for ones that are supposed to be
"stock calibration" (yeah, maybe) and if you want to
drive it richer then 3.0Kohms (orange/black.red) will
do that. I went from 2.7K to 3.0K after lightly porting
the SLP unit I had with a rat-tail file and this brought
it back to original (fairly, if not exactly stock) trims.
Attached Thumbnails 85 mm MAF question!!!-slp_resistor_origplace.jpg  
Old 12-24-2007, 08:45 PM
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I am not throwing any DTC codes since I have been running this MAF. I do notice that when at idle the LTFT then to get close to +25 but never reach it. Once the car is moving the LTFT stay below +11 but not below +5.

Here is a pic of the MAF that I have in my car. The resistor on mine is red, blue, yellow, red, brown. Is this the stock 85 mm Corvette sensor??
Attached Thumbnails 85 mm MAF question!!!-000_0193.jpg   85 mm MAF question!!!-000_0194.jpg  
Old 12-24-2007, 11:42 PM
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one alternative is go to a dyno with a maf translator and try to dial it in . only thing is unless you get a good deal on both you will spend close to that of some software .
Old 12-25-2007, 01:40 AM
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Stock Delphi MAFs do not have this resistor. SLP MAFs
are screened too. It may be another outfit doing the
same kind of deal, Pace perhaps. You might want to
try changing out resistor to the more common values
and see, presuming you are good enough at soldering
to keep it from rattlng loose and getting sucked up.
At least until better options come along.
Old 12-25-2007, 08:54 AM
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Thanks JimmyBlue! I will try to get a hold of SLP and Pace tomorrow and see what they have to say.

Does anyone who is using an 85 mm MAF have a similar code engraved on the top of the sensor?? (see pic)
Attached Thumbnails 85 mm MAF question!!!-000_0196.jpg  


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