Diesel starting problems

[E_T_V]

To those with oil burners out there:

I'm having a few starting problems with my camper. Recently it has been getting harrder and harder to start.

Starting from cold it'll fire first time but then stop. It'll repeat this over and over and over again for about 10 times when eventually it'll go. Sometimes when it goes it'll only idle lumpily even if my foot is flat on the floor, but if I release it it still idles lumpily. After 30 seconds or so it then runs absolutely fine.

Also now it won't start from hot either. it turns over and over but doesn't fire. If I leave it for 5 mins after it has stopped, or even less, then it'll fire first time and run happily.

I've replaced 3 of the glow plugs (the 4th has the correct resistance but is a pain in the bum to get out). I've also changed the fuel filter and it passes its MOT emmissions tests and the injectors have been subjected to lots of injector cleaner.

I was thinking fuel pump but as it runs fine flat out I'm not sure.

Any ideas?

[e692wtt]

This sounds like there is an air leak into the fuel system - the hole may not be large enough to let diesel out, but is large enough to let air in and allow fuel to return to the tank. This hole will probably be at one of the joints on the diesel pipework between tank and injectors... could be anywhere. The fuel filter housing is often favourite, especially after the filter has been changed. Try putting grease round all the unions you can find on the diesel pipes (especially between the Injector pump and the tank) and if this cures the problem remove the grease from one joint each day until you find the faulty one.

Failing that, I believe there is a 'lift pump' much like the engine-mounted petrol pump on an early S-series engine, that pumps diesel from the tank to the Injector pump, and it is possible this has failed? I seem to recall that the diaphragm fails, but it used to be available as a service item. I could be wrong on this though, as performance throughout the engine speed range would be poor...

I would say 'air leak' is favourite.

[E_T_V]

Well seeing as it got through its MOT yesterday I have treated it to a new fuel lift pump. I've yet to fit it, but it occurred to me that a hole in the rubber diaphram would also let air back into the tank. Whilst I am fitting it I'll also remake all the union joints and seal with PTFE tape.

I had to hunt high and low for someone who could get a fuel pump, interestingly there wasn't one listed for a maestro at all, however there was one listed for the turbo diesel monty. I'm pretty sure they will be the same however the one I've just got doesn't have a nice "knob" on the top of it to prime it, instead you have to reach underneath to do it.