2007 Volvo Penta 5.0 GXI Fuel Pump issue

[kkennedy34]

Like most Volvo Penta owners, I have been dealing with a fuel delivery problem. I removed and disassembled both fuel cells and thoroughly cleaned both the high and low pressure pump screens, fuel resivoir etc. I also cleaned the fuel pressure sensor and anti siphon valve at the tank. I am getting 50psi at the fuel rail but get low or no reading on the low pressure fuel pump. I isolated the low pressure pump and it does get voltage and seems to run (makes pumping noise). The engine fires up fine and idles fine and holds 50psi as I increase rpm. My question is, would I be holding 50psi if the low pressure pump was not working? Could the low pressure release valve be giving me a false reading if it were defective? Any thoughts are appreciated..

 

[Scott Danforth]

low pressure pump draws from tank to fuel cell. high pressure pump pushes from fuel cell to motor. the pump either runs or it doesnt.

the pumps are airtex/carter units in a fuel cooler made by a heat-exchanger company.

 

[kkennedy34]

low pressure pump draws from tank to fuel cell. high pressure pump pushes from fuel cell to motor. the pump either runs or it doesnt.

the pumps are airtex/carter units in a fuel cooler made by a heat-exchanger company.

This is what is confusing me. If the low pressure pump is showing zero psi when tested with a fuel pressure tester wouldn't the boat be starved for fuel? Could there be an air leak in the pump or somewhere on the low side? There are no fuel leaks that I can detect.

 

[ESGWheel]

Not sure I 100% understand. With 50 PSI at the fuel rail thru the range of RPMs what is the fuel delivery issue you are experiencing? I.e. what caused you to post? Was it that you were simply curious about what your pump was outputting, and you see zero on the low pressure side so how can that be?

And to be sure you are measuring the pump correctly here is an excellent link on how to: link.

Please (1) post the symptoms you are experiencing and (2) let us know the pressure testing you are doing is same as video (I assume yes, but what to be sure…..) Thanks.

 

[kkennedy34]

Not sure I 100% understand. With 50 PSI at the fuel rail thru the range of RPMs what is the fuel delivery issue you are experiencing? I.e. what caused you to post? Was it that you were simply curious about what your pump was outputting, and you see zero on the low pressure side so how can that be?

And to be sure you are measuring the pump correctly here is an excellent link on how to: link.

Please (1) post the symptoms you are experiencing and (2) let us know the pressure testing you are doing is same as video (I assume yes, but what to be sure…..) Thanks.

Sorry I didn't provide more background. I initially had hard starting and rough idle issues. Eventually the engine would stall about 10-20 seconds after start up. I actually found the ManCave videos and followed the exact proceedure you linked with a fuel pressure tester. I went further and pulled the pump apart and checked and cleaned everything back to the tank. When I re installed the pump assembly the hard start/stalling issues went away but I am still getting 0 psi at the low pressure pump with the fuel pressure tester.

So I guess my main question is, If I'm getting 0psi on the low side would it even be possible to get 50psi consistently on the high side. Is it more likely either a false reading or an air leak somewhere that could cause the high pressure pump to be overworked and will eventually cause fuel delivery issues to the injectors?

 

[ESGWheel]

I cannot attest to if the HP pump would pull thru all the way back to the tank but sounds like it does - at least a little bit. Bottom line is you need a new pump.

Here is my suggestion and assumes you have an OEM fuel pump. Buy one of the AfterMarket (AM) pumps available at places like Amazon (link) and install. My experience with these has been positive but it’s not my long-term solution. Let me explain > with the AM pump installed and now all back to normal can enjoy boating while you send your OEM pump to Troy (mancave mechanic) for rebuilding. He will go thru it, replace the LP pump and remove the internal paint which may be part of your issue. His service is excellent, and you will get back a good OEM pump. Install that for the confidence it brings since its OEM and hang onto the AM one as a spare.

Also make sure you are cleaning out any paint debris from the pressure regulator, fuel rails, and even potentially from your injectors. IF you have little back specks / blobs in the regulator you can bet it’s in the injectors. Thus, servicing them is warranted. Read this thread (link) on the internal paint these pumps had and how to service the regulator (i.e. replace).

 

[kkennedy34]

thanks for the de

I cannot attest to if the HP pump would pull thru all the way back to the tank but sounds like it does - at least a little bit. Bottom line is you need a new pump.

Here is my suggestion and assumes you have an OEM fuel pump. Buy one of the AfterMarket (AM) pumps available at places like Amazon (link) and install. My experience with these has been positive but it’s not my long-term solution. Let me explain > with the AM pump installed and now all back to normal can enjoy boating while you send your OEM pump to Troy (mancave mechanic) for rebuilding. He will go thru it, replace the LP pump and remove the internal paint which may be part of your issue. His service is excellent, and you will get back a good OEM pump. Install that for the confidence it brings since its OEM and hang onto the AM one as a spare.

Also make sure you are cleaning out any paint debris from the pressure regulator, fuel rails, and even potentially from your injectors. IF you have little back specks / blobs in the regulator you can bet it’s in the injectors. Thus, servicing them is warranted. Read this thread (link) on the internal paint these pumps had and how to service the regulator (i.e. replace).

Thanks for the rundown on getting this solved. I think you're right on biting the bullet and getting the OEM pump refurbed by ManCave. I'll check out the aftermarket pump as a way to stay on the water until I get the OEM back.