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Discussion Starter #3
Iv had it on the jump leads pal the car just turns over but won't fire.
But fires off a bump start and drives.
 

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Sounds like too low rail pressure on start. In this case you can also start it by spraying some brake cleaner (as a burning accelerant) into intake manifold while cranking. Most likely caused leaky injector or failed o-ring on rail pressure regulator (at the back of HP fuel pump).
 

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Diagnostics can give a code for too low rail pressure and show the pressure while cranking (should be above 200 bar). You still have to measure injector leak off to rule out leaky injector as a cause for low rail pressure. If the injectors are OK it's most likely that o-ring on pressure sensor.
 

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Discussion Starter #7
Ok thanks. I'll have to get a leak off test kit and do it this week.
Could the pre supply pump be at fault it makes a noise when the ignition is turned but doesn't stop.
 

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Yep, pre-supply pump is a contender (and a regular failure point on these). They can fail outright, and/or leak - also the relay that sends power to them can give up. Also clagged fuel filters can be surprisingly unhelpful to starting rail pressures.

I would have to say that some noise from the pre-supply pump when you turn the ignition on (lasting about 30 seconds or so), is usually a good sign however. IIRC you can get a diagnostic read out on the pre-supply pressure and it should be about 4 bar.
 

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A failed inline fuel pump can't explain this if engine doesn't start normally but can be started by towing.
 

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Discussion Starter #10
Thanks.
The pre supply doesn't stop buzzing atall is this a problem.
Is the inline pump inside the fuel tank ?
 

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The inline pump is on the underside of the floor under the passenger seat. There is also a lift pump in the tank.

Clavurion's knowledge is almost certainly better than mine - both generally and regarding the inline pump! For what it's worth, I'm certainly aware that its failure will preclude starting on the key, however I'm also aware that the car will run without it. So, if the pump fails whilst the car is already running, it will continue to run although it won't rev fully. Hence, my wondering whether you might still be able to bump start it even with a dead intermediate pump. Ultimately it will depend on whether there is some ECU/electrical impediment to starting it even when it's being forced to turn over by being towed.
 

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Discussion Starter #12
The car does rev fully but its jearky through the rev range on acceleration and it floods the road in black smoke.
Would this be more likely a leaking injector ?
 

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Yes - black smoke would imply over fuelling (or under airing depending on how you look at these things). Black smoke combined with low rail pressure suggests a leaking injector.
 

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Discussion Starter #14
Ok thanks think I'll get it plugged into a diognostics tomorrow and see what codes it shows.
Will bump starting the car cause any further issues ?
 

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Potential catalytic converter damage if you end up with unburned fuel in it.

And, i guess, all the soot in the turbo vanes might risk problems if it's variable vane. And unburned diesel washing down the bores and diluting the engine oil in the sump.

Probably best to keep the running to a minimum to be on the safe side!

Note that leaking won't necessarily throw a code beyond low rail pressure - you need to do an old school leak off test.
 

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Discussion Starter #16
Thanks for the reply.
Just wondering how I could do a leak off test when I cant start it off the key could I bump it whilst I have the leak off test fitted or can I fit it once the car is started ?
 

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That's actually a really good question now I think about it... But reading back, I think Clavurion's probably answered that - ie spray a little brake cleaner fluid/ether into the air intake whilst cranking in order to get it going.

Or just pull all six injectors and get them tested - but that's probably about £30 each plus £90-£100 for each one that needs sorting out.
 
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