4.3 Volvo/Penta fuel pump not priming

[commander100]

I have a 1997 Glastron 185 fish/ski boat with a 4.3L V6 Volvo/Penta.<br /><br />When I first turn the key on, the fuel pump is supposed to run for 2 seconds to prime the motor. This doesn't happen. I read only 1.4 volts at the fuel pump relay coil, probably induced from turning the key on.<br /><br />If I jumper the pump to get gas into the motor, then disconnect jumper and put relay back, it will start and run normal. This tells me the relay and fuel pumps are OK.<br /><br />What would cause the relay not to pickup when first turning the key on, yet allow the engine to run fine once started? I don't have a scan tool, and my dealer mechanic ordered a fuel pump relay based on what I told him (still waiting for it), but I don't think that is going to fix the problem.<br /><br />My guess is some kind of sensor error telling the computer not to prime the engine, but what sensor to look at? And why if it is a bad sensor reading would the engine run once manually primed?<br />Appreciate any help.

 

[rodbolt]

Re: 4.3 Volvo/Penta fuel pump not priming

by the 1.4 volts I am guessing you have a bad connection someplace. the ECU will turn on the pump for 2 seconds or so then off. it should use the ground side to complete the circuit for the relay. I would carefully check all connections for corrosion. is this a TBI,MPI or carbed motor?<br />only the EFI motors have the 2 second pump run modes. do you have a harness diagram and an understanding of what the relay does and why? without it your sunk and tossing parts at it.