Diesel leak.Hi folks

[gloworm]

Hello folks, we have a 2007 2.3 ducato,
Sometime ago i noticed a fuel leak so started to investigate and i found its the fuel pipe that delivers fuel from fuel filter to injector pump halfway between the two there is a snap connector and that where it leaks,
Now the strange thing is it only leaks when the van is being driven and it only leaks when engine is on overrun, ie going down hill or approaching a jcn or roundabout anywhere where foot is off gas pedal,
It seems there is something pushing diesel back up fuel supply pipe and the weakest joint is snap connector,
I have renewed said pipes, fuel filter including housing, fuel tank cap,
The van runs & starts no problem, no smoke, no warning lights, i have spoken to 3 diesel specialists and all are baffled, anyone here got any idea's, TIA

 

[pagey]

the fuel is under pressure and it returns to the tank when not required ie on the over run when the engine under load it is using the fuel

 

[gloworm]

Hya Pagey
Thanks for reply, the problem is its leaking from the supply pipe, return pipe is ok,

 

[SandraL]

We had a diesel suzuki with a bosch cp3 high pressure pump. It had a solenoid valve operated on the overun to disconnect the 3rd piston in the high pressure pump to reduce pressure since fuel was not needed on the overun.
The valve sometimes did not operate, removing the solenoid allows the O ring on its shaft to be changed, the new soft O ring allowing the solenoid to operate. This fault brought up a fault code on the overun on our engine.
All diesels have a return to the fuel tank of unused fuel, easily seen by the second rubber hose on the injectors. The high pressure pump also has a return pipe for surplus fuel.
Suppose this return line was blocked, engine is not using fuel on overun so where does fuel go?
Possibly forced back the supply pipe?
I have little, ie next to no, knowledge so this is really a wild guess!!!!

 

[pagey]

Hya Pagey
Thanks for reply, the problem is its leaking from the supply pipe, return pipe is ok,

mmmm mis read the post

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[gloworm]

Hi SandraL.
Thank you for your reply, i think your idea of solonoid valve could be my problem and needs a looking at, the fuel return lines are all clear back to fuel tank,
Thanks again
Eric.