Just got sent home from tuner saying i have an issue. need advice

[01yellercobra]

A leak post MAF wouldn't affect the counts. But it would cause the motor to run like crap since metered air is escaping.

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[Mysticsnke]

^ +1

 

[workmangc]

A leak post MAF wouldn't affect the counts. But it would cause the motor to run like crap since metered air is escaping.

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Ah, admittedly, I was overlooking the FI.

I was thinking a vacuum leak that would allow additional airflow through somewhere else, causing the MAF to read low.

Since I'm still thinking about it, this was at idle, on a blow thru system. Let me explain what I am thinking, perhaps it's negligible, but may be good for discussion.

At idle, my car ,which is turbo, still draws vacuum. A leak post MAF, would (in theory) cause additional airflow to the motor lessening the amount of air flowing past the meter. I'm tempted to pull a vacuum line on mine and datalog just to see. I'm not saying it IS his cause, but I believe it could have an effect on AD counts. How much, of one would have to be seen.

Thoughts?

Another thing perhaps, although I have no firsthand experience with "calibrated" mafs, is that as I understand it, they skew the readings to trick the ecu to thinking less airflow has went past. Thus the car changes the pulsewidth to a smaller window so that less fuel in introduced into the motor.

So, wouldn't a calibrated MAF have to show less AD counts to trick the ecu?

 

[b00stin]

I swapped mass air flow sensors with a ba2400 sct meter .. Maf ad counts were around 150-160 at idle with a baseline tune for the meter

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[encasedmetal]

I swapped mass air flow sensors with a ba2400 sct meter .. Maf ad counts were around 150-160 at idle with a baseline tune for the meter

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that's where you should be.

 

[jmstekguy]

are you recircing your bypass valve or is it vented to atmosphere and where, do you have a pic of it?

 

[b00stin]

It was recirculated...I have switched to blow through now. What pics do u need?

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[b00stin]

are you recircing your bypass valve or is it vented to atmosphere and where, do you have a pic of it?

its in the passenger side fender now

 

[williesgt]

in a draw through maf sensor isnt the maf senor inbetween the air filter and the turbo inlet...if so if you have an air leak after the maf sensor you will have low maf counts due to the turbo will be sucking in unmeaterd air after the maf sensor...witch will make the car run lean not rich...

 

[b00stin]

we switched to a different Maf and the Maf counts were correct. I'm guessing because the pro-m is "calibrated" . Now I find out the tuner had a software issue when I was there so now I'm rescheduled for June 26th. Stay tuned lol

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