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Inconsistent MAF readings - Cobb subaru

Practical Reflash Tuning

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Hello all, I have a built legacy gt with Id1050x injectors and a Cobb sf intake. I have been struggling with scaling the MAF. I can get the numbers perfect on one day, but then they will be off by as much as 10% day to day. For example last night I had the car hitting my target of 11:1 perfectly last night, and today the car is hitting 11.5-11.8:1 in boost. This is not the first MAF I have scaled and I've never had this much trouble before. Any ideas would be appreciated.

Most likely you have some other compensation that isn't correct. Was the engine & air temperature in the normal range where the compensations are zero? What is different between the two sessions (air temp, coolant temp, baro pressure, fuel pressure, battery voltage, etc).

Are you sure the injector characterization data is correct?

I have a similar issues at the moment with 2014 EDM STI EJ257, stock ECU, using Ecuflash for flashing ang Romraider for logging. It has COBB cold air intake and BOV, eveything else is stock. I rescaled MAF with this exact CAI on previous 2014 EDM STI and no issues with fuel correction or open loop fueling. This car was crahsed, but CAI was not damaged and is on a new car, that is same year and with same stock setup. I assumed that MAF scale should be identical or at least close on the new car, but it is inconsistent as hell. Fuel trims at 2.2 MAF volts were +28%, after rescaling MAF, fuel trims at 2.2 volts are -23% (consistent throttle). During driving fuel trims are also inconsistent, it can be +25% at one moment and 5 minutes later at same MAF volts in -5% region.

It really seems to be a mechanical problem, but I don't know what to look for. If there would be leak somewhere, I would assume it's always there and fuel trims are in one direction, not all the way around.