VolvoBoater
New member
I have a 2005 Volvo 4.3 GL-A engine that has a starting problem. If I turn the key the engine will turn, but it won't start. It doesn't appear to be getting any fuel.
Diagnostics
I pulled the green wire (L post) on the alternator and jumpered it. The pump sounds like it's running, so I think that much is OK. Because the fuel relay is also switching properly when I did this (pump runs) I think that's OK too.
Because there diodes involved that can potentially go bad I also tested the wire from the alternator. I used a VOM set to ohms and put the hot lead at the alternator side and the negative probe in the 85 connector. It shows low resistance. I reversed the probes and it shows resistance at 1.0, so the diode is OK.
In reading several other posts on similar problems I learned that while starting, the pump gets power from the starting relay. On my engine this is located in the electronics box attached to the starboard riser. I tested the yellow/red wire the same way I did the alternator (green) wire. It shows low resistance from the starter relay to the fuel pump relay and 1.0 on the reverse, so it's also good.
I pulled the fuel filter off and poured its contents into a jar to check for water and sediment. It's clean, and the filter is new, so I doubt there is an issue there. The Holly 2bbl carb was just rebuilt and when I tested the engine it started and ran great, so there shouldn't be any issues there.
Just for grins I pulled the fuel supply hose and put an outboard priming ball and a section of clear hose on so I could see what was happening. I also checked all connections in the fuel system from the carb to the tank and they're tight, so no air leaks.
If I prime the system using the ball, I can start the engine and if I play with the throttle a bit I can keep it running. Once the engine has been started I can restart it without doing anything else. Although this worked, I don't really want to have to open up the engine compartment every time I start the engine.
This has me really frustrated and I've run out of stuff to try. The pump runs when it gets power, so the pump is good. The wires (and diodes) from the starter relay and alternator are also good (if my test was valid). The fuel pump relay seems good since it runs the pump when it gets power from the alternator (I didn't test power from the starter relay).
What else is there to test? Any ideas for things I might have missed would be appreciated.
Diagnostics
I pulled the green wire (L post) on the alternator and jumpered it. The pump sounds like it's running, so I think that much is OK. Because the fuel relay is also switching properly when I did this (pump runs) I think that's OK too.
Because there diodes involved that can potentially go bad I also tested the wire from the alternator. I used a VOM set to ohms and put the hot lead at the alternator side and the negative probe in the 85 connector. It shows low resistance. I reversed the probes and it shows resistance at 1.0, so the diode is OK.
In reading several other posts on similar problems I learned that while starting, the pump gets power from the starting relay. On my engine this is located in the electronics box attached to the starboard riser. I tested the yellow/red wire the same way I did the alternator (green) wire. It shows low resistance from the starter relay to the fuel pump relay and 1.0 on the reverse, so it's also good.
I pulled the fuel filter off and poured its contents into a jar to check for water and sediment. It's clean, and the filter is new, so I doubt there is an issue there. The Holly 2bbl carb was just rebuilt and when I tested the engine it started and ran great, so there shouldn't be any issues there.
Just for grins I pulled the fuel supply hose and put an outboard priming ball and a section of clear hose on so I could see what was happening. I also checked all connections in the fuel system from the carb to the tank and they're tight, so no air leaks.
If I prime the system using the ball, I can start the engine and if I play with the throttle a bit I can keep it running. Once the engine has been started I can restart it without doing anything else. Although this worked, I don't really want to have to open up the engine compartment every time I start the engine.
This has me really frustrated and I've run out of stuff to try. The pump runs when it gets power, so the pump is good. The wires (and diodes) from the starter relay and alternator are also good (if my test was valid). The fuel pump relay seems good since it runs the pump when it gets power from the alternator (I didn't test power from the starter relay).
What else is there to test? Any ideas for things I might have missed would be appreciated.