Volvo 5.0 GL Fuel Pump Troubleshooting

[schwa75]

1998 Volvo Penta 5.0GL, Fuel Pump P/N 3858261.

Ran the boat last week for a few hours, took on 40 gallons of fuel from a marina I have purchased from for years. Put the boat on the lift and flushed the engine. Came back this week and the boat started on the first crank and ran for about 60 seconds, before sputtering out. Recranked with no results. No fuel coming out of the jets when exercising the accelerator pump. Pulled the fuel filter. It was full to the brim. Dumped it in a glass jar - clean and water free. Checked voltage at the fuel pump when cranking, 12V present. Disconnected the fuel line from the carb and directed it to a catch vessel. Cranked twice for 30 seconds + each time, no fuel at all discharged. Pulled the pump and ran 12V to it on the bench. It is humming away! Submerged the intake in a cup of water, nothing discharged from the outlet. Poured water down the intake to prime the pump and it discharges! Dropped it in the cup and it continues to pump. Flushed the pump with WD40 in hopes it would rust out tonight...

Does this pump need to be primed? Why would it have lost prime after one week? Before last week, it had not been run in 8 weeks and still started on the first crank. Do I need a new fuel pump or do I just need to prime this pump from the outlet fitting?

Thanks all for your input,

Jason

 

[Don S]

Re: Volvo 5.0 GL Fuel Pump Troubleshooting

Was the screen on the inlet side of the pump clean?
You should never test with water. Diesel fuel, alcohol, parts cleaning solvent, but not water.
Was the pump actually running when you cranked the engine over?

 

[schwa75]

Re: Volvo 5.0 GL Fuel Pump Troubleshooting

Was the screen on the inlet side of the pump clean?
You should never test with water. Diesel fuel, alcohol, parts cleaning solvent, but not water.
Was the pump actually running when you cranked the engine over?

Inlet screen was clean. I know water was a bad idea, but I figured the thing was dead and would not pump, so that was just going to be a science experiment for the kids to work with this afternoon.

I could not hear the pump running when I was cranking the engine, but I did not get any fuel output from the line to a the funnel/jar arranagement I set up. I am planning to put the pump back on the engine tomorrow, but have to replace the 12.5A breaker as one of the posts broke when I was removing the wires (didn't realize the breaker and relay were on their own bracket). Thoughts on jumping this broken breaker by just mounting both rings on the good post? Should eliminate any chance of a spark, but leaves me open to an overcurrent situation.

What is the proper process for returning this pump (or a new pump) to service? Other than priming the fuel filter, is any further priming necessary?

Thanks again,

Jason

 

[Don S]

Re: Volvo 5.0 GL Fuel Pump Troubleshooting

When you install the pump, just make sure you use new orings. You do not want air leaks, or the pump WILL suck air and not gas. Item 2 in the link below.
http://www.volvopentastore.com/Fuel...*****.696730793--store_id.366--view_id.770805

You can also run the pump without the engine, by jumping the 30 and 87 terminals of the relay socket shown below.

It's also possible the relay or relay connections are faulty and the relay is not turning the pump on when cranking.
Here is a thread that covers troubleshooting that issue.
http://forums.iboats.com/showthread.php?p=2715541#post2715541

 

[schwa75]

Re: Volvo 5.0 GL Fuel Pump Troubleshooting

Thanks for the detailed guidance Don. I am ordering a few sets of O rings for testing and a new 12.5A auto fuse to replace the one with the rotted post. I should have everything by next weekend and will perform the troubleshooting as described in your post.

Jason

 

[schwa75]

Re: Volvo 5.0 GL Fuel Pump Troubleshooting

Don,

Turns out a bad battery cell was holding my relay voltage below 10v, not enough to pull the relay in. Switched batteries and the pump appears to be working fine, except for the huge crack in the outlet nipple that is now spraying fuel everywhere. Looks like an old injury that someone tried to cover up. Could have been a disaster on the water...waiting on a new nipple to arrive and then we should be back on the water. Thanks for the excellent troubleshooting guide.

Jason

 

[Geniusatlarge]

Re: Volvo 5.0 GL Fuel Pump Troubleshooting

I have a Volvo Penta GXI-G and I have blown 5 relays in the last week. The relays are extremely hot when I pull them to replace. All my connections are clean, just replaced the High pressure fuel pump just to be sure it wasn't that. It runs great for a while, then when I am at very slow speeds, I get a warning beep, then the relay goes out and my pump stops sending fuel. If I switch out the relay, it works fine.

 

[schwa75]

Re: Volvo 5.0 GL Fuel Pump Troubleshooting

I have the low output, carborated version. You have the high output injected version. I would start a new thread to get some help.