possible air lock in 2.5 diesel.....help.please

[Harrison]

Hi can anyone shed some light on this one please.
I recently had a clutch replaced on my 95 m plate 2.5 diesel and while it was up on ramps the mechanic noticed i had a diesel leak coming from one of the fuel lines going to the fuel filter, when i got home i had it up on ramps and removed the fuel line to see if i could repair it to tide me over till the new one i had on order came.
I patched it up and reconnected the fuel line, it started fine and ran for about 30 seconds and then started hunting and finally stopped.
it sounded like it had ran out of diesel but checking the gauge i still had half a tank.
I called out breakdown recovery who said that it was either the fuel pump that had packed up or air in the system. He tried turning it over but nothing.
My question is how easy is it to bleed the air out of the system with minimum fuss and is it easy enough to replace the fuel line that is ruptured?.

thanks very much in advance

[Nighthawk]

I take it that this is a 95 M with the smiley front.

The engine has a mechanical lift pump with runs off the camshaft, that will draw the fuel from the tank and push it up to the injection pump.

These pumps have been know to cause this sort of problem. sometimes they can't re prime after air has entered.

You have put the pipes back on the correct way round havent you?.....i've seen crossed pipes a few times on these. worth checking again.

If it is just air in the pump, you could open the injector pipes a turn or so and get someone to crank it over while you watch for the clear diesel to emerge. there is a bleed point on the bosch pump too, looks like an unused pipe sticking out of the side of the pump with a 14mm spanner size hex on it. unscrew that a couple of turns and crank it over.....beware lots of diesel will shoot out!!!

[Harrison]

Hi Nighthawk,
yeah i only took of the one pipe from the fuel filter and replaced it back the same.
I undone a couple of injectors tonight and tried turning it over but with all the trying the battery was a bit low so nothing really came out. it did look a bit wetter on the top of the injectors, but not much. so couldnt really tell if the pump was working or just not enouigh power in the battery to get a good flow going.

Are the pumps quite reliable or do they have a history of breaking down??
Also do i have to drop the tank to replace the fuel line from that end, it is easy enough to remove it from the fuel filter end

thanks again

[Nighthawk]

If the engine was running before it was in for the clutch repair, it should be ok now, you've only removed 1 pipe....which one?

The pipe work is simple really

Fuel Tank----------fuel pipe--------lift pump------fuel pipe-------filter head----fuel pipe------injection pump

then on the return side

injection pump-----fuel pipe-----fitler head--------fuel pipe*-------fuel tank

The * means that the leak off from the injectors joind this pipe.

They haven't trapped the fuel pipes between the bell housing and the engine have they? seen that a few times because they'll have needed to remove a steel bracket for the pipes on the top of the bell housing.

[Harrison]

Hi nighthawk,
Yeah it was the one with the leak off pipe that t's off from the fuel filter to the leak off points on top of the injectors. I pulled it off and puled it down to inspect the damage to it ,but to be honest i am gonna have to replace it anyway because of the rupture in the pipe anyways so that should iliminate that problem if the pipe has been twisted or bent in any way by me possibly when i had a look at it.
This should be my first port of call yeah before trying to bleed the system?

thanks again

[Nighthawk]

I'm a fan of retracing my steps, so i'd be under the van and having a good look at all the pipes tbh, especially where the go over the bell housing.

Problems on the return don't normall cause non starts unless the fuel has been allowed to drain back to the tank in the other pipes. Get the battery charged, replace the defective pipe......they are only push fit connectors and see what happens when you bleed it up.

[Harrison]

Thanks very much for your help on this night hawk,
I'll let you know how i get on when the new fuel pipe comes from ford and i fit it

cheers fella

[Nighthawk]

no probs m8

happy to help

[Harrison]

Nighthawk...

new prime pump and new fuel line...........result: starts first time every time


thanks very much for the advice m8

lee

[Nighthawk]

Happy to have helped