Chrisso
Senior Member
The Systems Operation for your Tier4 final/Euro IV fuel system states:
The valve is opened and closed by the ON/OFF of energizing the PCV [Pre-stroke Control Valve - fancy way of describing the fuel pump controller], which is controlled by the Engine ECM. The ON/OFF timing is controlled based on signals from various sensors to provide optimal rail pressure.
If you applied continuous current this explains why you got the "overpressurising" event. According to this description, you should be able to toggle your rigged-up external power source on and off to keep your fuel rail pressure in the 'happy' band. This probably isn't doing your brand new pump any good, but tell me... can you see the rail pressure responding to your 'toggling', if that makes sense? This could help identify a rail pressure sensor issue.
Silly question... Is ET showing cranking speed while engine is cranking? See if you can verify both crankshaft AND camshaft speed sensor signals. While your in ET, spend 5 mins and check there's no crazy parameters for....
Troubleshooting these really sucks. There's nearly always guesswork involved since specifications seem to be highly classified due to emissions regulations... which leads me to think replacing the fuel rail is the better option (gives you a new rail pressure sensor and discharge valve, and is cheaper than an ECM). The fact that it runs when you apply external power is promising... could possibly rule out debris blocking your injectors if anything.
I guess at this stage we're looking for any reason why the ECM would NOT command the fuel pump to 'pump'.
The valve is opened and closed by the ON/OFF of energizing the PCV [Pre-stroke Control Valve - fancy way of describing the fuel pump controller], which is controlled by the Engine ECM. The ON/OFF timing is controlled based on signals from various sensors to provide optimal rail pressure.
If you applied continuous current this explains why you got the "overpressurising" event. According to this description, you should be able to toggle your rigged-up external power source on and off to keep your fuel rail pressure in the 'happy' band. This probably isn't doing your brand new pump any good, but tell me... can you see the rail pressure responding to your 'toggling', if that makes sense? This could help identify a rail pressure sensor issue.
Silly question... Is ET showing cranking speed while engine is cranking? See if you can verify both crankshaft AND camshaft speed sensor signals. While your in ET, spend 5 mins and check there's no crazy parameters for....
Troubleshooting these really sucks. There's nearly always guesswork involved since specifications seem to be highly classified due to emissions regulations... which leads me to think replacing the fuel rail is the better option (gives you a new rail pressure sensor and discharge valve, and is cheaper than an ECM). The fact that it runs when you apply external power is promising... could possibly rule out debris blocking your injectors if anything.
I guess at this stage we're looking for any reason why the ECM would NOT command the fuel pump to 'pump'.
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