Diesel leak - rough running/starting?

[GreigM]

Looking for anyone to confirm a theory - I have an old stebox escort 1.8TD and its been struggling to start and once going sometimes starts then dies, but eventually I get it running it seems to run unevenly - sometimes even revving itself.

I thought it might be air in the fuel system, so when bleeding it down I noticed a drip coming from the pipe which connects the fuel filter to the fuel pump - only seems to leak when engine is just switched off.

So my theory is that this pipe will be feeding the fuel pump, and while running it is possibly sucking in air, causing all my problems, and once switched off the residual pressure in the system is pushing some fuel out the same leak...so replacing the pipe should cure all ills.....sound reasonable?

I know you'll be thinking "just replace the fking pipe" but its a £50 part and bangernomics don't work if you spend hundreds fault finding on your £300 car

[annodomini2]

The problem you may have asumming it is drawing air is something known as cavitation, basically as the pump pressurises the fuel at least 400bar-ish (modern stuff can exceed 2000!) the fuel is a non-compressable fluid, however the air is compressable and when it makes contact with a surface inside the pump it literally explodes and will carve little holes in the contacted surface.

This can literally destroy the inside of the pump.

If it has been drawing air for a long time then the pump could be screwed, if not it may just be the pipe needs changing.

Needs a first hand look by someone who knows what they are doing, i.e. independent diesel specialist.

However this may be against your bangernomics philisophy, someone may be able to offer better advice, but from the sound of it I'd say your pumps screwed.

[GreigM]

hope not - suppose either way I have to replace the leaking hose - will give that a try first and hope for the best....if not its off to the scrappy for a pump...thanks

[Steve_D]

GreigM said:

....if not its off to the scrappy for a pump...thanks

I would suggest off to the scrappy for the pipe. Last time I was in my local looking for coil packs I had trouble working my way through all the disesels.

Steve

[GreigM]

Good news - pipe replaced and runs like a dream (well as much of a dream as an old stbox escort with 100k on the clock can run) - total cost £20 as dealer had originally quoted for wrong part. Didn't realise quite how much a small leak in the system can affect a diesel.