300tdi air in fuel

hello

My disco has been down on power lately and also had stopped smoking when given the boot from the lights. I suspected the sedimenter was leaking air into the system as the filter bleed produces bubbles but also ordered molylube diesel purge to give the rest of the system a scrub out.

She is currently sat on the drive running on neat diesel purge with bubbles in the return feed. At first i was running it with the feed to the nearly new delphi lift pump, then with the filter intake hose in the purge but still air is coming out the return line. All connections before the injector pump are tight, the new fuel filter is in as tight as a ducks arse. Is any evidence of air inthe return feed normal, and if not how can i further work out where the fault lies. I will bypass the sedimenter as there is much less air now she is not running from the tank, but it would be nice to solve the matter entirely.

Many thanks

W

A quick update, running from the tank it has as much air in the return line as from the jug of purge.

You don't say which disco, but I'm assuming 200 or 300 Tdi.

This has been done to death on here, but the usual suspects are the injector spill pipes and the associated pipework. Fuel filter mounts can split too.. even it being too tight can push the seal sufficiently out of the way to cause issues. Lift pumps fail (regularly ) - a fuel filter half full is the normal tell tale ,,,,,

The intank doohicky (gauge and feed and return) can fall to bits, and the top does rust away

The sedimenter is, IMHO, an essential part of the system, and given that they not expensive, keep it - this cheapo part could save your rather more expensive FIP

Many thanks, its a 300tdi. Oddly it would appear to be an EDC with a manual gearbox and a cable operated injector pump retrofitted. It used to go like the clappers so I know it has been functional at some point.

I failed miserably to undo the fuel filter for inspection after getting carried away tightening it to try and exclude a leak from there, but when i changed it last week the old filter was full to the brim, i will warm it up with an air gun on sunday and try again to take it off.

Assorted copper washers and small bore fuel pipe orderd to address the spill rail.

I will report back on progress. Any further suggestions thankfully recieved.

What makes you thing it is an EDC?

Your title did say it was a 300tdi, @Disco1BFG must have missed it...LOL.

Cheers

neilly said:

What makes you thing it is an EDC?

Your title did say it was a 300tdi, @Disco1BFG must have missed it...LOL.

Cheers

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Ah, well, er the older I get, the more I miss

@123asd ... what makes you think it was EDC ? - Mine was EDC - but it's an auto, so presumably replacement engine with original FIP on ? or ???

It has the electropneumatic modulator and boost sensors bolted to the body, no airflow meter, and the throttle directly connected to the injector pump by a cable.

Interestingly whilst the diesel purge has now vastly improved its ability to make sizable puffs of black smoke on the overrun, and made it run a good bit smoother, a new clue has emerged...

The only time the thing gets near full throttle is when towing (for the most part it gets driven very much with conserving fuel in mind), as i had it apart the better half persuaded her father to chauffer her abd the horse to a competition only to find his car had a new loss of power on the motorway.

Jacked up the trailer, last adjusted its bearings and brakes six months back, one wheel sodding stiff to turn, two others dragging a little more than I would accept, and one spinning freely. Todays focus will therefore be on the trailer as the potential cause of the problem.

Dam horses..
Was it first time this year out for the box?

Hope you have sorted the fault out.

Check the fuel pipes where they enter/exit the fuel tank. The nylon to brass connector is known to crack and allow air in .. notalot ... but enough to make it less than enthusiastic to run quickly or hard. You might need to jetwash the area to see any cracks, it's in a 'bowl' where the fuel tank top and sender is, so any mud and silt gets washed in there too! I chiselled mine out .. quarry mud had set like concrete, but the nylon fitting still let air in!

Hicap phill said:

Dam horses..
Was it first time this year out for the box?

Hope you have sorted the fault out.

Click to expand...

The box averages two trips out a week all year round, and frustratingly all four wheels were spinning freely again when I got to it today. The wheel bearing a brake pivots on the suspect wheel got regreased none the less though.

Paul D said:

Check the fuel pipes where they enter/exit the fuel tank. The nylon to brass connector is known to crack and allow air in .. notalot ... but enough to make it less than enthusiastic to run quickly or hard. You might need to jetwash the area to see any cracks, it's in a 'bowl' where the fuel tank top and sender is, so any mud and silt gets washed in there too! I chiselled mine out .. quarry mud had set like concrete, but the nylon fitting still let air in!

Click to expand...

Once it arrives in the post i will to running a new fuel line from tank to lift pump and will give those a good look. Many thanks.

I sent the better half to plumb the new fuel line in whilst I did the timing belt and sure enough the nylon to brass bit snapped off.

I also changed the radiator, thermostat, and amcillary belt. Leaving off the air con drive belt seems to turn the air con button into extra electric cooling fans on demand so that is exactly what i have done (though i am hoping the radiator and thermostat replacement will make that superfluous).

A new sender has been ordered.

Would air entering the return side of the system alter the way she runs?