Mercruiser 5.0mpi fuel pump

[davelarkins1]

Hi all

New to this site seems really helpful congratulations for that, I have a mercruiser 5.0 mpi and hasnt been run since April, I do not have a oil pressure reading or temperature reading and the fuel pump runs constantly any help would be much appreciated

Cheers Dave from Perth WA

 

[Bondo]

Re: Mercruiser 5.0mpi fuel pump

Hi all

New to this site seems really helpful congratulations for that, I have a mercruiser 5.0 mpi and hasnt been run since April, I do not have a oil pressure reading or temperature reading and the fuel pump runs constantly any help would be much appreciated

Cheers Dave from Perth WA

Ayuh,.... We'll need alot more details,...
The fuel pump is Supposed to run, whenever the motor is runnin'...
the temp sensor is in the T-stat housing, check it's connections...
The Oil pressure sensor is beside the distributer, or down low on the portside of the block...

 

[davelarkins1]

Re: Mercruiser 5.0mpi fuel pump

Hey Bond-o

Thanks for the quick response, as soon as I turn the batteries on the fuel pump starts and continues running without the motor running. It just use to run for a few seconds. I have been checking the starbord side for the oil pressure sensor so now I can check again thanks
Davo

 

[Bondo]

Re: Mercruiser 5.0mpi fuel pump

Hey Bond-o

Thanks for the quick response, as soon as I turn the batteries on the fuel pump starts and continues running without the motor running. It just use to run for a few seconds. I have been checking the starbord side for the oil pressure sensor so now I can check again thanks
Davo

Ayuh,... It might be an ignition switch issue,...
The fuel pump shouldn't come on til the key is turned on...
Not the Battery switch...

That's the kinda Info, or back story We need,...

What else have ya done,..??

 

[Fun Times]

Re: Mercruiser 5.0mpi fuel pump

Since this is a MPI engine, The PCM turns on the Fuel pump for a few seconds at key up.

Normally when the fuel pump is stuck on your fuel pump relay is stuck on, Try tapping/hitting on the relays a little to see if the pump will turn off with key on. You may need a new relay, The relays are on top of the engine.

But since you also have no oil pressure reading or temperature reading, That would suggest you may have a bad wire connector somewhere. Depending on year/engine serial number the problem could just be at the ten pin cannon plug wire connector going to the engine from the helm.

 

[davelarkins1]

Re: Mercruiser 5.0mpi fuel pump

Thanks for your help all, the relay was the cause of the pump constantly running, I cleaned the electrical connections on the thermostat housing and the switch for the oil pressure gauge that was the only one I now have an issue with it went up a bit but my dipstick is at the add point, I will give it an oil and filter change and let you know how its all goin.
Gday from WA Dave












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