Ok, so here's the deal. Was screaming across the water when suddenly the motor sputtered out and stalled. Started back up and noticed it was in guardian mode. No overheat, water temp and oil pressure all normal. Limped back to the dock. Here's what we found:

Sea pressure is 1.9 psi at idle
Codes stored: 77 camshaft sensor, 132 crank sensor, 151 fuel pump relay

Motor sends off warning alarm at around 2500 rpm and cuts motor. To eliminate sea pump issues, I removed and replaced the impeller (which was in prett good shape). When I re-installed the psi was still quite a bit lower than the other motor (approx 2psi vs 9psi). I back flushed all the hoses and even checked the heat exchanger for blockage. The fuel filter was pulled and changed as well. I checked all the hoses, vacuum lines and iginition wires. Even replaced the sea pressure sensor on this motor. NOTHING!!

The only other difference I can tell is audible. The fuel pump on this motor sounds quite a bit different when the key is on compared to the other motor. Could it be a fuel pump? Help guys. My knuckles are busted and I've been stuck at the dock all weekend!!!

Thanks!

Chad

how many hours? with a crank and cam sensor i would suspect a timing chain skipped a tooth..do a compression test,that should tell you ...

sea pump,did you have the drive off slipped o ring?, check all hoses, and the one between the transom and the drive, could be pinched or sucking closed.

Find "Crayola Crazy" here on OSO. He knows alot of stuff about 496's and he might be able to help you out. He's got a bunch of spare parts too.

I've seen the cam and crank sensor codes many times but it's almost never the problem.

It's a pain but try swaping the fuel pumps and see if prob follows the pump. I would not even worry about those other codes not even for minute. They are an end result of the computer not liking something else.. They pop up often.

Of course it's a lot easier to check the fuel pressure on both and see if one pump is making better pressure.

Stock setting is 43psi on the 496.

Grab a 13mm wrench and lossen only the two outside bolts on the coolant tank and lift it up just enough to pop the tester fitting on.

Key on, engine off, should be right around 43. If you idle the engine with vacum line conected it's usually about 5 psi lower than key on engine off....

Thats what I am thinking. Gotta be a fuel pump issue, right? Want to find a way to hook a gauge up to the fuel pressure and see what it is reading. Pumps aren't the easiest thing to get accesss to.

Bobby is a good friend...already on the case. Thanks.

Covered in post # 5. Good luck -

You can get a $15 fuel Inj pressure gauge at Advance Auto Parts. Right next to your plastic coolant reservoir there is a valve with a cap on the fuel rail. You can screw it on there and take it for a ride while you have somebody watch the gauge. If the fuel pressure drops it will be obvious...

On the cool fuel system there are two different "screens" that can catch debris. Maybe you are starving it right at the pump?

or maybe

Only other thing related to make the pump act up is the solenoid/relay that is next to the ecu - swap them around and see what happens. (dont know the impact of these while running though) But that might explain the "fuel relay" alarm. They are $25 a piece - replace all of them and forget it...