[Richard748]

Hi guys i am having an problem with my ducati 748S i cannot get it to fire because the fuel pump wont prime i have checked the pump buy connecting it direct to the battery and it works fine i have checked the relays buy connecting them to the battery they click and beep on my tester . the bike cranks but with out the pump priming not joy no ridding . my dads 996R has a similar problem it runs perfect but every once in a while the pump does not prime then you leave it on for 15 20 min and it primes . pls help dying to ride my bike

 

[garylkendall]

check fuses and relay under seat. just a quick not prime if stop switch isnt in the run position

 

[Richard748]

My relays under the seat are working and put new fuses and the kill switch works I am pulling my hair out with this bike

 

[34566]

tttt

 

[MarkDCordell]

I'm having a similar problem about which I just posted. I have the Haynes manual and it appears that switching for the fuel pump relay is done by the ECU and on the -vdc side of the relay coil. That would explain why it runs for a few seconds then shuts off until the bike is started since there dosen't appear to be any pressure switches on the fuel system. I'm hoping someone may know of a better solution than replacing the ECU. I know this doesn't solve our problem but maybe head us in the right direction.

 

[cb4265]

As Gary said, firstly eliminate bad fuses and relay's.

These things aren't that complicated, we all just think the worst.

Craig

 

[MarkDCordell]

Having Same Fuel Pump Issue

Check my posts on "748 Fuel Pump Woes in KC". Looks like we have the same problem and I've just about decided to replace the ECU. This old girl is a demanding mistress.

 

[VtwinDave]

I had a problem with my 748s for years and i couldnt find what was wrong with it , i checked everything ecu/pump/relays under the seat and cleaned wire connecting blocks and nothing . You would turn the key and sometimes the pump would prime and sometimes it wouldnt , it had a mind of its own . I then changed the side stand relay down at the battery and now it works perfect .:dance:

 

[[email protected]]

We had a 748 in the shop with a similar problem and it turned out to be the kickstand safety. Check it out.

 

[Nick Doll]

Richard, what year is your 748? If it is pre 200 then it does not have a sidestand switch. Here is something I would try. Coming off the fp relay you will see two brown with white stripe wires. One will be larger in diameter and one smaller. Grab the smaller wire and splice a piece of wire into it and ground it to the ECU box or chassis. By doing this you are bypassing the ECU's control of turning on the FP replay from priming/running. Thus, the FP should run at all times. If this works then it is most likely the ECU that has a bad resistor in it. You can open it up to look for obvious issues, but if you don't see any then it is best to replace the ECU. Good luck.