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250 HPDI - no VST fuel pressure
Good morning BBC boards- so after reading many helpful threads on here I decided to tackle the project of changing out all of my fuel filters due to some rough running/surging and abrupt RPM loss at WOT. I changed all 10 of the mystery filters, the low pressure canister filter, both low pressure fuel pumps, the fuel water separator, the high pressure “can filter”, and cleaned/blew out all the injectors. After all this the boat ran flawlessly...for about 4 hours. After the boat sat for an hour or so while fishing I went to restart and had some trouble starting. Eventually got the motor started but couldn’t get over 1000 rpm without major surging and choking out. When I got home I still couldn’t start the motor. I noticed that when I cycled the key I normally hear the fuel pump motor cut on to pressurize the VST- This was not happening. I checked the Schrader and there is no pressure. After that I took apart the VST and bench tested the fuel pump motor… Everything checked out and the motor works fine. I checked the power supply to the pump motor while cycling the key- No voltage at all. I have checked the fuses on the starboard side of the motor as well as the Killswitch. For the life of me I cannot find out why I am not getting voltage. Am I missing something? Maybe ignition switch assembly fault, bad connection, or pinch in the wiring harness. Today I put in another key switch...still no luck and no power to the fuel pump motor in the VST. My last thought might be damage or short to the ECU?
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Born on th Llano Estacado
If you pulled the covers off the rear of the engine, there was a relay you had to unplug. That relay is what powers the VST pump. Make sure you got it plugged back in good. Same thing happened to me when I changed my pressure relief valve. I apparently didn't get the connector latched and it worked its way apart after an hour or so of run time.