Fuel pump issues

I have 1996 crusader 454xl engines. They have served me well with 2000+ hours on the engines. Recently I was cruising at 3600 rpm when my starboard engine quit. I could not get it to restart so I limped back to the marina on one. I did a quick diagnosis and found the my fuel pump wasn't cycling and my ignition alarm was sounding when I turned on the key. We traced the problem to the relay and swapped that out. The engine alarm sounded and the engine fired up. I thought all was well. I left the marina and ran about 30 minutes and boom the engine died again. This time I was able to get it to restart and then it would run and quit then run and quit again. I brought it back and we discovered that if I jumped the wires at the 10 am breaker in the box the engine would start. so we swapped out the 10 amp breaker. Again the engine started and the next day I left the marina. I ran about 45 minutes at cruising speed and turned back for the marina thinking problem solved. Just as I was doing my turn to back into my slip yep the engine killed again. In the slip I can get it to restart and run for maybe 3-5 minutes then it dies. I paid close attention to my oil pressure gauges thinking it my be an oil pressure issue but I noticed no change in oil pressure when the engine died.

Any ideas? Suggestions would be appreciated.

they have the electric fuel pumps, right?

if so, it could be the pump is dying or the infamous oil pressure safety switch is on the way out. best way to figure it out is to monitor the +12VDC wire feeding the fuel pump. if the engine dies and the +12VDC supply has disappeared, its likely the switch...if the supply is constant, I'd say it is the fuel pump.

After a bit of pondering, I think there is also a fuel pump relay...they are known to have finite service lives as well...

makomark said:

After a bit of pondering, I think there is also a fuel pump relay...they are known to have finite service lives as well...

Click to expand...

Thanks for your input. We swapped out the relay first. We were thinking the oil pressure sensor also so I think we will address that next.