disco wont start

hi new to this site just got 98 disco running fine but changed cam belt that was fine ran no problem then few days later changed oil and filters didnt bleed fuel system as had discos before never had to bother anyway this ran then next day wouldnt start only way can get to start is with return union on pump loosend one time i did get it going the indicators were started flashing any ideas please

your supposed to remove air as it can **** pump ,start with tank sender under plate in boot floor passenger side pipe is suction for lift pump they are often rotten ,then sedimentor (which i allways bypass ),lift pump ,fitting clear plastic pipe in between filter and front banjo on injection pump helps to see systems good not drawing air in future to at all rev levels ,bleed system by slacking front banjo with 3mm socket as this removes most air

jamesmartin said:

your supposed to remove air as it can **** pump ,start with tank sender under plate in boot floor passenger side pipe is suction for lift pump they are often rotten ,then sedimentor (which i allways bypass ),lift pump ,fitting clear plastic pipe in between filter and front banjo on injection pump helps to see systems good not drawing air in future to at all rev levels ,bleed system by slacking front banjo with 3mm socket as this removes most air

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thanks james will give that a go in morning

You don't need to remove the air, the Bosch system self bleeds, that’s also why there is no auto bleed on the filter assembly such as there was fitted to the CAV system.

I don’t see why suddenly you would have an air leak into the system at the sender or sedimenter because you did some maintenance. More likely to be directly related to something you did recently or disturbed.

Are your leak off pipes in good order, if these are not sealing properly they allow diesel to leak back to the tank, and can make starting difficult. You may have disturbed one. Get 3 pieces from a motor factor and push them on, takes 3minutes to do the job and could sort your issue.

Next time you go to start from cold, deck the throttle (this puts the Bosch pump into super cold start excess fuel mode - unlike the Lucas where doing this will impede starting) and see if that helps, if it does then the problem is almost certainly diesel leaking back.

they will self bleed ,but it is better for pump to bleed as much air as possible and leak offs on 300 dont effect running each injector pipe has oneway valve stop leak back, most discos ive seen have poor feed pipe so is good idea to check and repair if for nothing else to stop future problems, indicator lights flashing could indicate immobiliser fault

Leak off pipes on the 300tdi will not affect running no, but will affect starting if air can get in and allow diesel to run back, one way valve or not, diesel runs back and they don’t start well. The chances are that after the likely 100k or more one way valves are not perfect. It only takes a small space for a LOT of air to get through remember.

Ok leak off pipes can affect starting, just had to replace mine as they where all split. I was having problems starting so I check the obvious first so tank pick up ok, fuel sedimentor checked and clean, all pipes ok, lift pump working, changed fuel filter turned out all was ok. I started to think it was the fuel injection pump until I clocked that the leak off pipes where in **** state so replaced them now there is no starting problems that was last week.