That is very interesting. It's as high as 75 psi
I believe that's the case u literally see puffs of gas vapor come out of the plug holesInspecting that as well as the key fob battery are my next two steps. When I pulled the plugs I did not smell gas in the motor after cranking to test spark. Are the fuel injectors not being commanded to open?
I did get a reduced engine power message briefly when the care barely cranked a few days ago, it generated along with the P228d code.Well closed loop when the car is starting it needs the injectiors to be connected to pcm and that crankshaft position sensor my scanner gives me a little check mark for crankshaft position sensor everything else offline till car/ 02 sensors heats up . crank position sensor also tells injectors when to fire but it should throw a code for that torque to 15lbs. Idk about that code shutting things down but it should run on reduced engine power with a skewered fuel reading would take 10+ seconds cranking to start. Could start but be very difficult with reduced engine power mode.
The GM Repair Manual has a section on this, here are some thoughts.
Key fob bad transponder authentication
Crank Position Sensor
Engine must crank at 200 to 300 RPM
Fuel pressure and volume
Fuel injector nozzles blocked or restricted
Bad engine grounds, negative cab
Are you anywhere near Las Vegas? Happy to diagnose for free if you areI quickly drove to the grocery store and 10 minutes later returned to the parking lot to drive home and the car would not start. I attempted to jumpstart it as well as fluttering the gas pedal while it cranked. Only once did it ever begin to even fire but died seconds later with a P228D code generated, I suspect sense it did not run correctly all kinds of errors were going on and that maybe simply a symptom.
(fuses) checked all fuses
(battery)Battery has 12.4VDC
(fuel)Low pressure side of fuel pump 66 PSI, replaced fuel pump
(spark)Pulled a spark plug and coil and confirmed spark during cranking, although it needs new spark plugs it was running minutes before
(air)Cleaned MAF, replaced MAF
(crankshaft position) replaced crankshaft position sensor
I have attached a screen shot of my OBDII scanner information during cranking.
Some looking has shown there also exists a timing chain defect possibility; two more sensors on the fuel rail itself; injectors; ECM
I am unsure what my next steps should be. Please advise.