lazy starting 525tds - BMW Forum

bmnkyharris9 · 09-11-2008, 03:42 PM

Hi Everyone I am new to this forum and I am looking for some help with a starting problem, I have had my 1995 525tds touring automatic for a couple of months know and on the whole it is very good who ever since i bought it the car has not started first time.

The fuel seams to be going back to the tank as the fuel lines become empty after a time. i.e if the bonnet is up and I am trying to start it then I can see the fuel lines filling with fuel.

I recently changed the fuel filter and this seemed to cure the problem for a day or two but then the old reluctance to start returned, I have been told that this is probably due to a air leek in the fuel system.

Has this happened to anybody else or can anybody help shed some light.

mgad · 09-30-2008, 05:56 AM

check for any holes in the fuel lines

marti5 · 09-30-2008, 06:00 AM

Also get underneath and check the tank is ok.

MADDOUG · 09-30-2008, 02:33 PM

Check the unions on fuel filter where pipes plug in these have 'o' rings that can fail and let air in,also lift boot carpet and take off oval cover (six screws) to access top of tank and check for leaks on pipes,the clear pipe from filter to injector pump can also split and leak,a leak here will be hard to spot as it will run down side of pump.It may only be a minute leak that is letting air in so do not expect to find diesel swilling around,saying that the pump seals can leak on the rear of pump,there is a side plate that has an 'o' ring or similar and they can leak(its between pump and block) on the front where pump bolts to block also,very hard to spot so clean area and dust down with talc if you suspect a leak from pump as it will easily show up then.Never ever remove top cover of pump as its timing will get screwed up (even half a mill out and engine will run rough).Check your injector leakoff pipes as well.the seals can be changed if you are a competent mechanic and remove pump,but do a google search on vp37 pumps and get info on drilling and pinning top cover when removing.vegtableoildiesel.co.uk has in depth features on this as well.

bmnkyharris9 · 10-06-2008, 07:26 AM

At the weekend I fitted a non return valve into the fuel system in between the Deisel filter and the injecter pump early signs are that it has fixed the issue as it is preventing the fuel from draining back to the tank.

I will keep you updated as to if it is a good fix or not.