Good Morning everyone I hope you are doing well today.

I have been having an issue with my cobalt SS since I have changed the Supercharged LSJ to Turbo LSJ. I essentially put my own turbo kit together and it is having some issues. I will break it down though for those to help.

The car is having an issue where the Mass Airflow Sensor is reading its highest reading on the scale and getting pegged under initial throttle blip, or tip in. It also happens if I let go of the throttle and then get back into it while the car is moving.

I am not sure what the issue with this could be, but it could be a number of factors since it only happened when I did specific modification changes after I initial turboed the car.

When I initially turboed the car I left the injectors and tune that came with the car in it and it ran fine, I even had the blow off valve in the wrong location past the MAF letting air escape and dump fuel under deceleration but it still ran fine.

I then in one sitting changed the Fuel pump, the injectors with some used siemens deka 80lbs and changed the BOV location as well as started using e85. We began to tune from there, and that is where we started seeing this maf pegging right away.

Please keep in mind this car is not meant to have a blow through mass airflow sensor either and that is what is running now. But either way I am not sure what is causing this issue, it could be that I messed up the wiring to the fuel pump causing an internal electrical issue where the maf is pegging due to incorrect readings under initial throttle. Or the injectors having an issue, or even something else. Other then that the car runs fine, AFR's are where they need to be and im unsure as to what is going on.

Any thoughts are appreciated and im here to help with any questions regarding my issue or providing any additional information.

Thanks again,

 

my only thought would be something electrical, id guess its EMI causing it. where is the maf located in the car, is it or the wiring anywhere near the alternator or coils?

might help if you can post a log

 

Is it tuned? Lol

 

You say you moved the BOV to before the MAF, how much before? Maybe there is a surge of outside air over it when the BOV changes state initially, i've seen them pull open at idle and then snap shut as soon as you touch the throttle.

Is the MAF spike at the same value? Meaning, if the slope goes 1200-1400--10000--1800--2000... is it always in the same part of the ramp? I would suggest just a bad sensor if that's the case.

 

lol yeah it's tuned. we thought it was a turbulence issue, so he redid the cold side where the maf is and same issue, I haven't much time to diagnose it but he swapped maf sensors and no change.