Tripped Fuel Pump Circuit Breaker

[whitesharkseeker]

My fuel pump breaker tripped during while launching my boat and I couldn't start it back up. I have a 1996 Volvo Penta 5.7Gi and that problem has never happened before. Discovered the issue after getting home and engine fired right up. Is this a concern? What problem(s) would cause that breaker to trip? I want to place my boat in a slip this weekend and fix any problems before hand.

Thanks, Eric 22' Davis

 

[Don S]

Re: Tripped Fuel Pump Circuit Breaker

Could be nothing more than a faulty breaker. It does happen, and I have replaced many. Before you spend the money to replace it, by a cheap fuse holder and install the same size fuse as the circuit breaker was rated and hook it up in place of the circuit breaker. Then run the engine and see if it blows. Does the pump sound different than normal? It could also be a failing pump. Sorry, no way to say for sure which is the problem.

 

[whitesharkseeker]

Re: Tripped Fuel Pump Circuit Breaker

Don, thanks for the advice and quick reply. I really appreciate it.

-Eric 22' Davis

 

[whitesharkseeker]

Re: Tripped Fuel Pump Circuit Breaker

Ok, used a cheap fuse holder with 20 amp fuse and hooked it in place then started the engine. The fuse blew immediately and engine died. So maybe the fuel pump? Was hoping it was the less expensive fix. Not sure if it was making a noisy sound as the engine keeps dying but my last boating trip I didn't notice any unusual sounds.

Thanks, Eric 22' Davis

 

[Don S]

Re: Tripped Fuel Pump Circuit Breaker

Disconnect the electrical connector to both fuel pumps. Then try it again and see if the fuse blows. If it does, you have a wiring problem, if not, plug the pumps in one at a time and find out which one is blowing the fuse.

The pumps should both run for 2 seconds with just the key on, without starting the engine. Do they blow then, or do you have to actually start the engine first?

 

[whitesharkseeker]

Re: Tripped Fuel Pump Circuit Breaker

Hi Don,

Ok, I disconnected one fuel pump (see picture) and started the engine. It ran with no problems! Then I turned it off, plugged the wires back in and started the engine and the 20 amp fuse blew. Guess that's the troublesome fuel pump? I didn't think it would run with the wires disconnected. My finger on the first picture shows the plug that was disconnected from the fuel pump.

Thanks, Eric

 

[Don S]

Re: Tripped Fuel Pump Circuit Breaker

It was running with the fuel that was in the VST which means you high pressure pump works fine. The pump that is bad is the low pressure pump that feeds the VST and high pressure pump.

 

[whitesharkseeker]

Re: Tripped Fuel Pump Circuit Breaker

Thanks so much Don! Is it a difficult task to change the low pressure pump? Just ran the boat with the low pressure wires disconnected and ran fine. Hooked the low pressure pump wires back up and engine stalled with circuit breaker tripped after 10 seconds. Again, appreciate your fast reply and help! Lastly, if that were to happen off the coast, could I disconnect the low pressure wires and still run the boat?

-Eric 22' Davis

 

[Don S]

Re: Tripped Fuel Pump Circuit Breaker

Your high pressure pump may be pulling fuel through the low pressure pump. That normally doesn't happen, and I doubt you would get enough fuel through the pump to run the boat under load. But it, like anything else, is worth a try when your stranded.

 

[whitesharkseeker]

Re: Tripped Fuel Pump Circuit Breaker

Oh yes, forgot to say that when I felt the low-pressure pump after the circuit breaker tripped and engine stalled the front of it was warm. Not sure if that's a pertinent finding or not. Also noted a ground wire on the top of my engine block nearby that had a cracked insulation coating but otherwise still attached. Not sure if that is a significant finding either. Here's a pic.

Thanks again, Eric

 

[Don S]

Re: Tripped Fuel Pump Circuit Breaker

Warm, Cold, makes no difference. If it blows a 20A fuse, it's junk.

Replace the ground wire before it becomes a problem.

 

[whitesharkseeker]

Re: Tripped Fuel Pump Circuit Breaker

Will do! Thanks, Don.

-Eric

 

[whitesharkseeker]

Re: Tripped Fuel Pump Circuit Breaker

Follow up: boat fired right up and ran well after I installed a new low-pressure fuel pump. The Volvo Penta dealer told me that the fuel pump was an unlikely problem and reported those pumps as bullet proof and thought I had an occlusion in the fuel tank or lines.

Anyway, just want to thank Don for all his help. You are truly an expert and huge help troubleshooting engine problems. Don't think you get enough appreciation.

Thanks again, Eric 22' Davis

 

[Don S]

Re: Tripped Fuel Pump Circuit Breaker

Your dealer must live in a different world than the rest of us, those pumps are far from bullet proof. Even the aftermarket guys found it's a profitable market and sell cheaper (less reliable) replicas.