Start problem bmw 525 tds (e34)

[asse]

Hello guys

Thanks for a great website

I have following problem on my diesel bmw:

After the car has not run for 8 hours or more it is really difficult to start. In the mornings for example it starts for half a second then dies right away. After that i have to crank the starter motor over for 2 minutes or so before it starts. Starter engine and batteri is good (untill i kill it from overusage).

Glow plugs are all new and i changed the small magnetic vent that allows the diesel to flow from the diesel pump.

I have read that the diesel can run back to the tank if the fuel lines are leaky - causing air to enter. And then i have read that the problem could be a bad injector.

I have spent quite a lot allready at the mechanics and it seems they dont know what the problem is (its a bosch specialist hmmm)

Any help is appreciated

/Anders

[colo525i]

Doesn't quite sound like leaky fuel lines, those will generally cause problems as you drive too. The car will surge or stall at random in most cases. Have you checked the glow plugs to see that they are heating up? (use a thermometer, those things can burn your hands!) Went through 2 sets in a brother's Mercedes before we realized the glow plug relay and timer system were broken. Also, run a can or two of lubromoly diesel purge through the fuel system. This stuff can clean up the injectors, get rid of a lot of problems that are related to dirty fuel system.

[DaveVoorhis]

Checked the compression?

[dan0235]

i had exactly the same prob, tried glow plugs, new filter, parking down hill all that did was falling out with the boss (too many late starts) the main boss, wife (taking her car when when she was still in bed!!!), what i found out was that the pump in the tank was goosed, so instead of replacing that mega £££££££ i just put a hand primer (the type you find on a out board engine/motor boat) in the fuel line between the fuel filter and the eng (the yellowish clear pipe), if she dosen't start (bites at 1st then just cranks over) i pop the lid squeeze the primer until hardish, then start her!!, also makes priming the system after filter change easy!

[skr]

check fuel pump. pull the fuel line from the filter to the pump, turn the key (don't crank) and see if fuel comes out. if it doesn't, it's the pump in the tank. you should allso check injectors and glow plugs but if it fires up and then dies it's 99% fuel related.

[Ferret]

Slightly unrelated vehicle, but I had the same problem in my old peugeot 205 TD - turned out the non return valves in the fuel system had packed in. It's the only real problem with the diesel fuel system that could cause this.

I dont know where they are on the 525td, but they'll be either on the tank pump or the injector pump. If there's a fuel filter under the bonnet - this usually also contains them.

I suppose the only other possibility is that some immobilisers kill a diesel engine after allowing it to start... (Apparently stops dry cranking) or your fuel shut off solenoid (if it exists on this variant - and it should) is goosed.