Thread: Bleeding the fuel system 300TDi

To prime the system, you have to manually operate the lift pump by pumping the lever underneath the pump itself.

Mind you, you don't have to do this as the easy way to do it (provided you have enough battery power) is to just crank the engine until it jumps into life.

As for the original problem...

Have you checked the top end of the injector pump??

• Pop off the cover by undoing the 4x bolts.
• Check the condition of the rubber diaphragm.
• Mark the position of the diaphragm (so that it can be replaced exactly where it came from).
• Lift the diaphragm & check the condition underneath.
• Push down on the diaphragm retaining nut to make sure there is free movement in the unit.
• Reassemble...

Basically, what you're looking for is any signs of corrosion which will prevent the mechanism from moving freely.

If it isn't moving freely, then this will prevent the pump adding the extra fuel required when the turbo is on boost.

HTH

M

Two things worth looking at.
When did you last clean out the fuel sedimentor?
Have you checked the condition of the 2 pipe elbows on top of the fuel sender? They corrode and let air into the fuel lines, result can be no power.

Originally Posted by nicedayforit

Two things worth looking at.
When did you last clean out the fuel sedimentor?
Have you checked the condition of the 2 pipe elbows on top of the fuel sender? They corrode and let air into the fuel lines, result can be no power.

Agree: check the fuel sedimentor for blockage. It is mounted on the inside chassis rail, drivers side next to the rear diff input.
Rob

I've had a similar problem with a 300TDi Defender. It would run but no power.

After hours of investigation we eventually tried feeding the lift pump from a Vegemite jar of diesel and off she went!!

Air was getting in where the fuel line connected to the fuel tank (the one on the side, not the top one, which I think is the return line on a defender). Gunked it up with Araldite, as the plastic connector thingy was a bit dodgy, and that sorted it out.

Would be good if you could put a bit of clear tubing before the lift pump to see if you have a clear feed of diesel, or if there are any bubbles in it. I have not tried this - just an idea to see if there is air in the fuel lines.

HTH
David

Another point of possible air ingress into the fuel system is around the flat rubber/neoprene washer on the sedimenter drain plug. The washer develops a small ridge after it has been in for a while and if caught up when replacing can suck air.

It happened to me at Eighty Mile Beach (WA) and as no replacement was available, I simply turned it over, refitted it and problem was solved.

I discovered the source of the problem after four hours of checking everything I could and finally pressurising the system which showed the leak point.

BTW, I found the drain plug pretty useless for draining the sedimenter and that the best way was to dismantle the whole unit and give it a thorough clean.

Originally Posted by Xtreme

Another point of possible air ingress into the fuel system is around the flat rubber/neoprene washer on the sedimenter drain plug. The washer develops a small ridge after it has been in for a while and if caught up when replacing can suck air.

It happened to me at Eighty Mile Beach (WA) and as no replacement was available, I simply turned it over, refitted it and problem was solved.

I discovered the source of the problem after four hours of checking everything I could and finally pressurising the system which showed the leak point.

BTW, I found the drain plug pretty useless for draining the sedimenter and that the best way was to dismantle the whole unit and give it a thorough clean.

i have already cleaned it out about a month back, so i might take it off again and check it out..i went all around the bloody truck today with soapy water to see if i can find anything but nothing seems to be leaking. BUT have not check the sedimenter for leaks..when i checked it the first time it was to empty it out to see if there was any difference but there wasnt..

cheers simon

have you had another disco 300tdi driver drive your car for a comparison....??

I had the same thing happen to me..how ever mine was in my head, when things get changed and tweaked and you notice a difference...its not uncommon to adjust to the feel of the car quickly to then feel like its back to running like a hobbled mule..when in fact not much has changed..

Just an idea

Originally Posted by dullbird

have you had another disco 300tdi driver drive your car for a comparison....??

I had the same thing happen to me..how ever mine was in my head, when things get changed and tweaked and you notice a difference...its not uncommon to adjust to the feel of the car quickly to then feel like its back to running like a hobbled mule..when in fact not much has changed..

Just an idea

Are u saying that I'm crazy and imaging things!!!!!!!!! Lolol I know what ya mean but there is a change there some where within the fuel area. If I leave the car to idle alittle it changes from a rough/slow to a smooth/fast and that's when it runs great. Something is not opening/closing right.