Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Fuel Pump Problem Has me baffled?

[Jolley]

Do you have a spare pump you can try?.... These are similar problems to when my pump was playing up at Mallory in 2010 (on a 583, but even so). We replaced everything and wiggled every part of loom with engine running.... Eventually cured with new pump (mine had an elec pump on it). Mine would tickover fine and run fine for 5 laps... Then the gremlins would strike.

Or the tank breather?.... Run it with cap left slightly open. It is a long shot.... But just maybe enough of a vacuum could be formed to overpower the pump?

[Chaz]

Neil you can borrow anything you need off my 916 try the complete tank with pump maybe?

[antonye]

I have a spare tank (my trackday tank) you can borrow if you want to eliminate/confirm it's a pump/breather/line problem?

[dunlop0_1]

Thanks guys but I have had two different pumps and press regulators on the bike with no change. All pipes/hoses are clear and intact.

[antonye]

Is your vent valve fitted the correct way round? Are the vent hoses clear? Is the tank breather (the lines in the tank itself) clear? Are the fuel lines kinking when you replace the tank? Is there a kink in a fuel line futher down to the throttle bodies?

[dunlop0_1]

Yep all clear.
If the harness is a possible issue I was considering this.
The pump has a 12v feed when the ignition is turned on. The ECU then turns the earth on until the pump is up to pressure then turns it off. When the ECU gets a signal from the ignition sensor it turns the earth on again so the engine will run. So if I run a seperate fused/switched live from the battery to the pump and a seperate earth from the pump to the corresponding pin on ECU this in my mind would eliminate any of the existing wiring and possible problem?

[chrisw]

Chafing wire. Had the wire on the fuel pump connector chafing on the top the engine on my 999.

[antonye]

Also try a new fuel pump relay?

[skidlids]

Originally Posted by dunlop0_1

Yep all clear.
If the harness is a possible issue I was considering this.
The pump has a 12v feed when the ignition is turned on. The ECU then turns the earth on until the pump is up to pressure then turns it off. When the ECU gets a signal from the ignition sensor it turns the earth on again so the engine will run.

Somebody rewired it then or is the test meter leads connected wrong as normally the pumps Earth goes directly to earth and the 12 volt feed is supplied by one of the engine management relays with the status of the relay controlled by the ECU, the same relay should also put 12 volts on to the coils at the same time as putting it onto the pump

[dunlop0_1]

Originally Posted by skidlids

Somebody rewired it then or is the test meter leads connected wrong as normally the pumps Earth goes directly to earth and the 12 volt feed is supplied by one of the engine management relays with the status of the relay controlled by the ECU, the same relay should also put 12 volts on to the coils at the same time as putting it onto the pump

Cheers Kev, I actually got that inf from ducati.ms. I've just made a temp harness which runs the pump on it's own. If it works when riding the bike it at least points me towards the wiring albeit from the relay's and or the ecu.

The biggest problem is i have to ride the bike for the problem to occur. Sitting the garage it's fine.