Sprinter starts on push but not with key

[mrfwonderful2000]

Its a 311 sprinter van that has a strong battery & will turn over quickly but not even try to fire but will start very easily with a slight push! the fuel filter has been replaced but to no avail! Any ideas?

 

[IAN MAC]

Sounds like air in the system. Dont always believe when its meant to be a self bleeding system. Try slacken off the injector pipes to let the air out as you turn it over. If your confident thats not the problem then it could be down to a bad earth.

 

[mrfwonderful2000]

Once started with the slightest push it will run forever but if the engine is switched off and a restart is attempted with a key seconds later it will keep turning over without starting! Over the past few weeks it had been getting more difficult to start! Do you still think it may be an airlock or bad earth?

 

[IAN MAC]

Long range diagnosis not easy, but both these ideas cost you nothing to check. Process of elimination.

 

[Daeths]

Once started with the slightest push it will run forever but if the engine is switched off and a restart is attempted with a key seconds later it will keep turning over without starting! Over the past few weeks it had been getting more difficult to start! Do you still think it may be an airlock or bad earth?

There are people on this forum (much) better qualified then me, but my two pennyworths is to discount the air in the system (unless it is massive leak). From my experience if it is air in the fuel line once you eventually get it going it is fine for many hours after. Surely the simple check would be to crank it and look at the fuel lines for air bubbles.

Good luck

Adam

 

[oigle]

Suggest the problem has to be electrical. Seems that maybe things like pumps etc are not working in the "start" position of the key but are working OK in the "on" position. Check wiring and fuses. I'm no expert in this area but seems logical.

 

[mister_cee333]

My vote is a faulty injector.

When you have it running look at the fuel return pipe (at the filter) for bubbles. Any big bubbles would be a symptom.

I had a similar sprinter problem and apparently they are prone to this fault, especially injector no. 2 or 3, and especially 02 or 52 reg.

Total cost for diagnosis, removal, repair and refitting was around £200 if i remember correctly, from a diesel specialist.

 

[Mole2000]

I tend to agree with mister cee333, my 52 reg 313 had the same problem and it was an injector, infact all my injectors were replaced under warranty. they fail to hold pressure so don't inject!

 

[mrfwonderful2000]

Sorted

The symtoms are most definitely air in fuel system!
Which off course can be caused by many things, injectors included!
On this occasion it was caused by 12 dozzed fuel seals (o rings) on the common rail, some of them had a flat spot that let air in! Thanks to everyone for your help!