2001 Volvo Penta 5.0 sporadic no fuel

[Daniel048225]

I have a 2001 Volvo Penta 5.0 that will run fine and then all of the sudden sputter and die and upon checking the carb it will be dry. I had this happen Saturday after only running the boat for 20 minutes and then yesterday it happened again after running the boat about 3 hours. Yesterday I took the incoming fuel line to the fuel pump off and had gas, removed the line from the pump to the carb and nothing (even while trying to start the boat). I used a test light and couldnt find any power going to the fuel pump relay but I also didnt have a schematic so I am not confident in where I was placing the light. During the downtime event yesterday the boat sat about 1.5 hrs and then started and ran fine. Since this problem is so sporadic can anyone help me out on some things to check next time this happens?

 

[Alaboat]

This sounds much like the situation with my boat that I think I resolved yesterday. Read the the thread (long one) on 4.3 starving for fuel. I finally pulled my fuel tank yesterday and found one of those round cardboard seals from the lid of fuel treatment bottle in my tank. It was sucking up to the fuel pickup tube and stopping fuel flow randomly.

 

[alldodge]

used a test light and couldnt find any power going to the fuel pump relay

Sounds like your loosing power to the pump relay. Being a carb motor I'm assuming its a GL something model, please confirm.

Below is for a GL-C/D and the fuel pump relay is turned on while cranking by the Yellow/Red wire coming from the start relay thru a diode. Once started the relay is then powered by the Green wire thru another diode.

When the relay is energized it transfers power from the Red wire which comes from a 7.5 amp fuse, thru the contacts to the pump.

Your issue may be as simple as the relay has gone bad. You can verify this by checking for power while the motor is cranking on pin 85. If you have power and the pump is not running its the relay.

Can also jump across pins 30 and 87 which will turn the pump on if the fuse is not blown. Could also be a bad connection, but in any case yours sounds like an electrical issue with the pump

 

[Daniel048225]

Thank you for everyones response. I had fuel to the pump just not to the carb and the easiest thing to try is the relay. Since this comes and goes whenever it wants I know I wouldn't be lucky enough for it to happen in the yard.

 

[Bt Doctur]

the fuel pump is powered during starting thru a diode in the start circuit.Once the motor is running the power comes from the alt to power the pump thru the diode.There is no direct battery connection to the fuel pump from the key switch
Main power is from a fuse or circuit breaker directly to the relay. You could also have the ground from the fuel pump or relay getting corroded.
The part I hate is the alt supplying the power instead of the ign switch, alt goes bad you lose the fuel pump.This can be corrected by installing a oil pressure switch and powering that off the ign on wiring

 

[Bt Doctur]

 

[Daniel048225]

Okay it's done it again. I replaced the relay just hoping that was it but I have no power on terminal 85 when attempting to crank the boat. If I jump 30 and 87 the pump will run. So when the boat is cranking I have no power from ignition.

 

[alldodge]

There is another thread may just be the ECM, but first try checking the 12V power and the 5V powerad similar to yours going on with similar problems. muc goes thru some very good troubleshooting methods and how to figure this one out. Need to measure your 5V and 12V power to see if it is what's causing the ECM not to energize the pump

Since yours is intermentant I don't think it's the ecm, but a bad connection or sensor

https://forums.iboats.com/forum/engi...n-t-fire/page3

 

[Daniel048225]

So I wasn't using a volt meter but a test light since I was on the water and didn't think about my meter.

I was curious so I took the fuel line off going to the card, jumped the relay and the fuel pump ran but no fuel for almost 5-8 seconds. Once fiel cam out I connected the line, jumped the relay again to run the pump, and hit the accelerator lever a couple times and all good. No problems the rest of the afternoon. Does this sound familiar?

 

[alldodge]

Oh crud, my mistake sorry, you have a carb and I got it mixed up with the MPI

Sounds like the typical electrical gremlin. Your loosing power to the pump so just takes so long before you run out of fuel in the carb. Need to clean the connections and look close at the diodes, then replace the relay, there fairly cheap. If that doesn't fix the issue it will take more wire and connection tracing.

Note, to keep the pump running once started comes from the alternator thru a diode

 

[Daniel048225]

What don't make since is as soon as I "primed" the fuel pump everything worked great. Really makes me doubt what I saw with my test light. If it was a bad connection or electrical problem that wouldn't have fixed it. The tank was also full so I plan on running it down and start the day just below 3/4 to see if that helps. Any ideas?

 

[alldodge]

Test light doen't provide much info,it just says some power is there, but may not be enough to do the job.

Need a meter to trace power

 

[kenny nunez]

If after all the electrical checks have been made and the problem is still there then there may be something lodged in the suction line in the tank. There might be a fine funnel shaped filter inside of the suction line. It does not take much to clog it up. If there is one pull it out and pitch it.