Troubleshooting Volvo 5.0 GL-B Fuel Pump

[Jim Wilkins]

My otherwise always reliable 2003 Volvo 5.0 GL-B engine stopped a few days ago while my son was towing some friends on tubes. It stopped at speed, with no warning. Wouldn't start. While getting towed to the dock (only a couple of hundred yards away), it started again, but only at idle, and then quit after about 10 seconds. I changed the fuel/water separator, but no affect. Then I looked down the carburetor (not fuel injected), and saw no evidence of fuel when either advancing the throttle at idle, or when turning the engine over. So...what else should I check, and/or how do I confirm that it is the $235 fuel pump before I spend the $$? What else should I check first? Thanks!

[Bond-o]

Ayuh,...Welcome Aboard,...
Is there Gas in the tank,..??
Is there a restriction preventing the gas getting from the tank to the fuel pump,..??
Remove,+ extend the fuel lne, after the fuel pump into a container,+ crank the motor,.. Get Gas,..??

[Don S]

While getting towed to the dock (only a couple of hundred yards away), it started again, but only at idle, and then quit after about 10 seconds.

Will it keep doing this? I mean starting then stopping after 10 or 20 seconds?

[mikeneal]

It gets voltage from two sources, the starter relay when cranking then alternator when engine is running. There is fuel pump relay at the pump and you can check for voltage there when cranking/running if it will start. If it is getting power then pump is bad. ( not unheard of, but could also be other things) Don S has posted links to the factory manual and that has all the info you need.

[Jim Wilkins]

After two or three efforts to start it at the dock, it would only fire up when the throttle was advanced, and for just a few seconds. No longer started just at idle. Then I removed and drained the fuel/water separator (installed new at beginning of season). Looked fine; no water in fuel. Refilled same fuel/water separator with gas (for prime), reinstalled, and tried to start. No firing whatsoever under any throttle position. That's when I began to look down the throat of the carboretor and found no evidence of fuel. And yes, the gas tank is almost full, both based on gauge and recent filling to full previous weekend. No more than 2 hours on boat after filling tank.

[Jim Wilkins]

Will it keep doing this? I mean starting then stopping after 10 or 20 seconds?

Don S,

After two or three efforts to start it at the dock, it would only fire up when the throttle was advanced, and for just a few seconds. No longer started just at idle. Then I removed and drained the fuel/water separator (installed new at beginning of season). Looked fine; no water in fuel. Refilled same fuel/water separator with gas (for prime), reinstalled, and tried to start. No firing whatsoever under any throttle position. That's when I began to look down the throat of the carboretor and found no evidence of fuel. And yes, the gas tank is almost full, both based on gauge and recent filling to full previous weekend. No more than 2 hours on boat after filling tank.

Jim

[Jim Wilkins]

I've done some more troubleshooting by taking the two-lead electrical connector off the pump and using a multi-meter checking for voltage on the two contacts when attempting to start the engine. I got readings of zero voltage while the engine was turning over. Seems like the pump may be fine, but gets no power. Two questions:
(1) Is there a fuse that provides power to the electrical relay that I ought to check before replacing the relay?
(2) Can I jumper 12 volts directly from the battery to the pump to check if the pump works fine, and if so, should I use a fuse (what amperage?) in the jumper line?

Jim