Hi, Recently, I have been troubleshooting an issue with my fuel rail pressure sensor on my 2012 MCS. A few months ago, I bought the car and is was running fairly well but had a CEL for misfiring and a few other things). I replaced the spark plugs, ignition coils, and fuel injectors. After that the car would not start and I read some where that if the car starts with the fuel rail pressure sensor disconnected then the sensor is bad. So I then disconnected the sensor and the car fired right up but was limited to about 4K RPM, which also prevented the turbo from kicking in. I received a CEL for P0193 (all others cleared) which indicated the fuel pressure was high/sensor failed high. After several weeks finally tracking down the correct sensor replacement it and got the same issue. Additionally, by this time, I replaced the fuel filter, low pressure supply fuel hose to the HPFP and the HPFP (new bosch unit from RockAuto).

For troubleshooting, I placed the key in and on and checked the wiring for the sensor connector and found the three wires were 5v, 0V, and 5v. I was told that the sensor wire should be 0.6v with the car on so I suspected a short of the reference and supply wires. I then disconnected the associated wiring harness bundle from the ECU and read 5V on both A22 and A24 terminals (correspond to the sensor signal and reference lines). I am at a loss now and ready to take it to someone else that can figure this out as it eats up my weekends and kills my bad back leaning over the engine. I don't want to risk causing further issues with the car and not being able to figure out what's wrong with it.
The only way the car runs is with the fuel rail pressure sensor electrically disconnected.

Any thoughts/recommendations?

 

I was getting the fuel rail pressure code and it turned out to be the High Pressure Fuel Pump.

 

Where did you buy the high pressure fuel pump?

 

I purchased at the mini dealership, salty $600 but solved the issue.