Hello all,
Hoping to draw some sage wisdom on some strange CJAA behaviors.
I have been having frequent hiccups/jolts in the power band around 2000 rpm very light throttle. I pulled MAF data showing very sharp dips (the same dips induced taking foot off throttle completely) while maintaining light pressure and speed. The car ran about as well on power but smoother with the MAF unplugged so I went ahead and replaced it.
When I drove to pick up the new MAF I left it unplugged for the entire drive and I did not get one single hiccup nor did I get one single deviation in EGR values in 45 minutes. After installing the new MAF, the car behaves a slight bit better (idle smoothed out doesn’t feel like it dips rpms too low when braking to a stop) but it does again have these sharp deviations in MAF/EGR values and has some of the jerkiness associated, although again probably is improved from what it was. My assumption is the EGR value gets confused as my tuner says it calculates the values based on the MAF. I have a dynamic EGR tune and ran logs from cold to confirm it closes off properly.
I’m at a loss for what is happening with the MAF values. I mapped throttle input to make sure it wasn’t losing value from that sensor since the dip looks the same on the VCDS scope. That sensor read consistent values. I also mapped boost and fuel delivery and they’re both equal in requested v. actual.
Hoping to draw some sage wisdom on some strange CJAA behaviors.
I have been having frequent hiccups/jolts in the power band around 2000 rpm very light throttle. I pulled MAF data showing very sharp dips (the same dips induced taking foot off throttle completely) while maintaining light pressure and speed. The car ran about as well on power but smoother with the MAF unplugged so I went ahead and replaced it.
When I drove to pick up the new MAF I left it unplugged for the entire drive and I did not get one single hiccup nor did I get one single deviation in EGR values in 45 minutes. After installing the new MAF, the car behaves a slight bit better (idle smoothed out doesn’t feel like it dips rpms too low when braking to a stop) but it does again have these sharp deviations in MAF/EGR values and has some of the jerkiness associated, although again probably is improved from what it was. My assumption is the EGR value gets confused as my tuner says it calculates the values based on the MAF. I have a dynamic EGR tune and ran logs from cold to confirm it closes off properly.
I’m at a loss for what is happening with the MAF values. I mapped throttle input to make sure it wasn’t losing value from that sensor since the dip looks the same on the VCDS scope. That sensor read consistent values. I also mapped boost and fuel delivery and they’re both equal in requested v. actual.
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