06 mcx apex in tank fuel pump problem?

[925rotax]

06 apex 270 hp w no secoundary pump. the sled starts and then shuts off. I checked the power to the intank fuel pump. The pump has 12 v power at cranking and when the engine fires. The 12 volt power is lost and the sled dies? Anyone know where the fuel pump harness gets its power from. Its a buddies sled and we are hoping to get out tmrw

 

[mbarryracing]

Are you getting any codes? If no oil pressure then the fuel pump turns off.

 

[925rotax]

no codes

 

[925rotax]

as soon as it fires the fuel pump loses its 12v supply

 

[mbarryracing]

How long is "as soon as"? a second or two, or the engine doesn't even have a chance to make a revolution after you release the key from start position?
Can you just cycle the key a few times and hear the pump run the few moments each time during it's prime cycle?

 

[925rotax]

while cranking there is 12v at pump. When it imediatly fires it runs 1-2 secounds and dies, runs out of fuel.When the sled fires and runs the 1-2 secounds. There is no power to the pump during the engine running ,only at cranking? I can hear the pump while cranking.

 

[925rotax]

I got home and turned my ignition to on and you can hear the system prime. My sled 06 mcx apex 310 w secoundary pump. His sled does not make the initial prime noise. I can hear the pump on his when i add a 12 v seperate source to pump and ground. It doesnt prime the system like mine [noise sound ].

 

[mbarryracing]

Try swapping the fuel pump relay, I think it's one of the ones in the left foot well.

 

[925rotax]

thanks mbarryracing for your time! buddy had pulled out his powerblock. the one that the accessory 12v boosting lead goes to w a 40 amp and 2 10 amp fuses. he cleaned it because of corrosion andPUT IT BACK IN BACKWARDS. gold to negative. Thanks again!!