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Too many variables..


Ridgeracer

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Hello all....I had a theft incident with my car which required me to replace my FMIC, MAF sensor, BPV, and AVO intake. The car was dial in perfect and my fuel trims for A +-5% B - D +-1 percent. Now when I pull up my LV for fuel trims after 50 miles of driving, the car is adding 10% more fuel across the board. Is it possible for the fuels trims to be this far off with a new MAF sensor (0 miles vs old one that had 131K miles) and a new clean filter (same intake the original tune scaled for)? I can't really see the new FMIC causing this since the car is adding fuel across all ranges. I checked for possible post MAF leaks, confirmed that MAF sensor is not loose in the housing, all clamps are tight. Only thing I can think of is that the old MAF and filter were both dirty and old. I had not cleaned them in at least 20K miles.
"Gimme mines Balboa...Gimme mines".....Clubber Lang - Mr. T
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Well I don't have any leaks. Checked the car over and over and over. Checked ALL vacuum lines and sensors. Everthing is fine. I suspect I just will have to rescale the MAF again. I think just like the AEM intake, there are manufacturing variations between AVO intakes as well in relation to the MAF sensor position in the tube. +10% across the board on the fuel trims.

 

Just spoke to one of the techs at Rallitek and they suspect its a variation from the old to new sensor.

"Gimme mines Balboa...Gimme mines".....Clubber Lang - Mr. T
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I see that all the time at work. Sensors change and degrade over time causing readings that will drift. There are also differences in manufacturing that can cause one to read differently from another.

I think you are on the right track by re-scaling.

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Hopefully by this Monday. I need a new cable for datalogging/flashing. My old Tactrix cable is intermitently working with LV and RR datalogger. However is will not work period with ECU flash. Just driving in CL for now.
"Gimme mines Balboa...Gimme mines".....Clubber Lang - Mr. T
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Sorry to hear about the theft. :(

 

I haven't actually heard of variation between MAF sensors, but with electronic components in general there's always a tolerance of some sort. 5% either way is pretty typical and +/- 10% isn't unusual. After ruling out boost leaks / vac leaks I think I'd just go with it.

 

Check the turbo inlet for leaks too if you haven't already. Sometimes they tear and/or slide off of the compressor inlet. I spent an hour or two re-aligning mine today, it was hardly touching the compressor on one side.

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Totally agree with you both since all the trims are in the same direction. On the bright side I guess I have a little more head room up top now if I can get E85 since MAF/V is lower than before...

 

NSFW....I use the more robust 08-09 OEM turbo inlet. No tears there either.

"Gimme mines Balboa...Gimme mines".....Clubber Lang - Mr. T
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