2002 volvo penta 4.6 gl-j wiring diagram--- no fuel pump!

[fordpwr460]

HI folks, new to the board, see if anyone can help with a wiring diagram or ideas for this. I got a fuel pump that does not work, even after its running, it will run off carb cleaner/gas, for a few seconds then out, (no fuel obviously), this has a small slimmer relay PN 3841366, it gets better though.....this all started when the old fuel pump popped a fuse, so I hard wired the pump thinking it just got gummed up. huge POP, smoked. OK, so I hard wired a locked up pump....it was dead anyway right!....bear in mind no boat wiring was disturbed, this was bench checked. Now with a new fuel pump, I got no power to the pump, while cranking OR already running. So i'm thinking these diodes are popped? (fuses all checked and replaced 1 and has not popped again). Also a big note,,,,when I probe the wires to the fuel pump, it has ground, but when I put the test light on the ground to pickup "HOT" it immediately spins the motor? power going backwards up to the relay and engergizing the start wire? that AND the boats starter auto-engages WHILE its running!! went from a locked up fuel pump to some nightmare!! any help or ideas would be appreciated!! thanks

 

[fordpwr460]

sorry, typo....4.3...fat finger

 

[GA_Boater]

Welcome aboard.

Without being there to see anything, I'll offer the guess that when you hard wired the pump, you smoked the harness and melted insulation on the wires. That's what fuses do - Protect the wiring, not the device.

 

[fordpwr460]

no, I hard wired the pump AFTER removal off the boat, on the bench. No hard wiring has been done at all. sorry if I didn't make that clear in the original post.

 

[alldodge]

Would post a pic of the wiring but iboats has an issue with IE 11 still. :facepalm:

From my diagram I see 2 relays, one main power and the other fuel pump. Also there are 2 diodes, one from Alternator and other from main power relay.

Remove the diodes and measure with a ohm meter. Could also jump across the main power diode to see if it will start to run

 

[fordpwr460]

Thank you sir! I didn't want to tear apart the harness looking for 1 diode when there are 2 like you stated. Defintely has a issue with something in there. I can make it run obviously off gas with 2 people...but the autostart/engage along with this leads me to power going back UP. Thanks again. I'll post the final result for the next poor fellow!

 

[fordpwr460]

SOLVED!!! Thanks for all the ideas and help. After probing and testing per you guys ideas, I did DISCONNECT AND CHECK the BIG round "MAIN" cannon plug to the motor, however on this "GL-J" motor, (not sure about others) but it has a short main harness to the motor (common to the big round one) on this one. About 12-14" long. One end plugs in the back of the main fuse box on top of the motor (smaller rectangle about 10 pin), and then goes has the round connection on the other end. When I pulled the rectangle connector from the back loose to pull the whole 12" harness, I found the rectangle one to be FULL of water, literally ran out. And sure enough the yellow/red "start" wire and fuel pump wire was RIGHT next to the larger RED constant hot. ***this gave me BOTH the problems***, the autostart (shorted across), and the intermittent fuel pump power. not sure why they put both those main wires so close in the harness, butttt.....they did. Cleaned up and all good to go now. No diode or wiring problems. HOWEVER....on a future note for those replacing the ELECTRIC FUEL PUMP PN# 3858261. If you are buying a "aftermarket" one, I tried 2 different vendors and got in the mail HIGH PRESSURE pumps, seems to be a rash of them out there from what I found on the net, I'm not the only one. So I got mad and got a used OEM (which was locked up via ebay), sooooooooo, this just make my troubles worse. 4 fuel pumps later and ton of hours chasing wires, i'm back in business. thanks for all your help! Sometimes it pays to go OEM. Really caused a delay waiting a week at a time for a NEW "correct" pump.

 

[alldodge]

Great and thanks for coming back and letting us know the fix. :thumb:

 

[fordpwr460]

since you had the wiring diagram is there any chance you can see the wiring for the oil pressure system? I have the alarm going off, and light on, and no gauge! I thought that the systems were independent?? when I remove the single wire from the lower "switch" the alarm and light goes out. I checked the "switch" with a test light only, no ground when not running, grounded and lit after its running. soooooo....the switch should be good? its not a variable resistor is it? (the lower one) on the block. Changed the upper one also, no change. Probably needs a separate post....but figured I would ask, and BTW, this has been this way a LONG time, not associated with the initial topic

 

[alldodge]

Gauges have 12V and ground wires. They have a sense lead which goes to a variable resistor so as pressure increases the dial moves.

Alarms and lights have 12V but no ground going to them. To test them all you have to do is place a ground on the lead going to any of the senders (switches). So 12V is on one side and the other goes to a switch mounted on the motor. When the motor is off the switch should show continuity from the post to ground. When motor is started, and pressure builds above 5 psi, the switch opens and the alarm/light will go off.

So if the light or alarm is staying ON, the switch is either bad, a resistor sender was used instead or a switch, or you have a problem