2005 350 Mag dropping fuel pressure under load

[Fun Times]

At the end of the day, nice job in your diagnostic testing done.

 

[Scott06]

Update here. There was a 1/4” drill socket used to plug the line during repower stuck in the line. I’d call that a fuel restriction LOL. I’m going to test tomorrow as the north wind was howling today on Lake Huron, gotta think that was the problem. No idea if I or a helper shoved the line on with that fitting still in there. Ridiculous!

Always the simple stuff . Great job finding it

 

[jrglombo]

Second update - no more fuel problems after several trips out. But my ignition kept getting killed again. Checked my wiring again and I started to check move the wiring around towards the coil pack and when I moved the spark plug wires around engine stalled and beeped like you just turned the key off and back on. If I put some rpm to it at the dock and moved the plug wires towards CAN line it would do the same thing. I had the old set of wires still (mercruiser brand) and I put them on that side of engine and rerouted CAN line to not be near plug wires. YIKES. What a crazy thing, I’m hoping my new set of plug wires was bad, but have read and was even told here that plug wires can do some weird stuff.

 

[alldodge]

Thanks for the update but I'm not seeing how plug wires will kill a motor unless its burning thru the jacket of receiving wire

Might be loose/corroded connection on the engine connector