Attention: TDR Forum Junkies 
I had all nine (yes, 9 ISB's 
) back to the dealer for the 504 free injection/lift pump/sensor/reprogram. Now, my first new lift pump went out. The problem that I can't figure is that the pressure sensor will not set a code (779) untill the sensor sees ZERO psi. Why zero? Why can't the program be set to say, seven psi?
Now I have had this bus on the road for x miles w/zero supply. A mechanical gauge reads 3 psi at 800 rpm and 0 at 3000 rpm no load. It reads 9 psi when the ignition is "keyed to activate"
There is not the manpower at this operation to install an electrical gauge on NINE engines/buses.
The 504 is intended to alert me of a potential low supply issue.
) back to the dealer for the 504 free injection/lift pump/sensor/reprogram. Now, my first new lift pump went out. The problem that I can't figure is that the pressure sensor will not set a code (779) untill the sensor sees ZERO psi. Why zero? Why can't the program be set to say, seven psi? Now I have had this bus on the road for x miles w/zero supply. A mechanical gauge reads 3 psi at 800 rpm and 0 at 3000 rpm no load. It reads 9 psi when the ignition is "keyed to activate"
There is not the manpower at this operation to install an electrical gauge on NINE engines/buses.
The 504 is intended to alert me of a potential low supply issue.
