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Discussion Starter #1 (Edited)
Hi folks,

Anyone happen to have a good schematic of the fuel system showing relative positions of parts? e.g. Sender to HP Pump to Filter to Common Rail to Injectors, if that happens to be the right order?

Car won't start and the fuel supply is suspect. Possibly needing bled.

We were trying to progress logically along the system. In the picture attached, am I right in thinking that the two pipes with white and green connectors are the fuel send and return respectively from the LP / sender? We took the white one off and cranked the car and got no fuel out. We then took the white connector off the top of the sender and cranked again and got no fuel out of the LP / sender. This is suggesting that the low pressure lift pump might not be delivering to the engine.

Anyone see any flaw in our thinking, just in case a more experienced eye points out anything obvious if you know the hardware?

Cheers,
Ally
 

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You are correct that these are the fuel send and return pipes.
There won't be any fuel coming out of them however as the fuel is sucked up by the high pressure pump on the engine.
There is no lifter pump in the tank hence you have a primer bulb (the rectangular item at the bottom of your picture).
 

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Put the pipes back on and don't mess with things that you know nothing about

Then squeeze the primer bulb until it gets hard of it does not get hard after lots of squeezes then you may have a leak on the fuel system letting air in
 

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Discussion Starter #5 (Edited)
Ash, thanks for your constructive input. Having tried to pump the primer and apparently not being able to pressurise the system we suspected there was a leak. That was why we started from one end of the system for progressive elimination. However looking over the Haynes description it includes an LP lift pump which is quoted as in the sender unit, and quotes a separate HP pump. This would seem sensible to have an LP system to feed the HP system. I work on aircraft engines in the past and this is exactly what the LP system does. Is the Haynes manual wrong or am I missing some other detail? Perhaps you have either an LO pump or a primer but not both?

Trustme: all you've managed to do is assume the two folks who were working on the car 'know nothing' and suggest an apparent air leak which had already been stated. All I did was ask a system layout question. If you don't want to offer an answer, then fair enough but a lack of 407 specific knowledge is not the same as knowing nothing.
 

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There is no lift pump if the car has a primer so IF you have no fuel in the primer it wont start.

Haynes think every car is the same its not only some have lift pumps mainly bosch systems but later bosch systems no longer needed it.

If you really have a fuel feed issue then its most likely something to do with the pipework on the engine where it goes under the air filter housing.
 

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Basically all the rubber lines are the low pressure system: primer, filter, return lines.. and all the metal lines are the high pressure system: fuel pump -> injectors, pressure sensor. That's the way I think of it anyway.

I recently had what I thought was a fuel line leak (not starting and floppy primer) but it turned out to be a faulty fuel regulator (it sends the fuel to either the high pressure line, or back into the low pressure loop).

In my case the regulator was sticking so all the fuel was just going from the fuel pump, back around the low pressure loop again, and it was leaking too, hence the floppy primer.

I'm still fairly new here so don't take my word as gospel, but it's the way I understand it.
 

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Discussion Starter #9
Full marks GI Joe. Take a bow sir.

I have had the car in a garage as I am maxed out on time with work. It's ready now. The garage found a stuck HP fuel solenoid. Using a high pressure adapter they pumped diesel back and forward and freed it off. Oh and to add insult to injury, three out of four glow plugs were gone too!
 

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Full marks GI Joe. Take a bow sir.

I have had the car in a garage as I am maxed out on time with work. It's ready now. The garage found a stuck HP fuel solenoid. Using a high pressure adapter they pumped diesel back and forward and freed it off. Oh and to add insult to injury, three out of four glow plugs were gone too!
Nice one! :)
I'd say keep an eye on it though. Mine would stick, and then unstick randomly in a few days. Or if I bump started it, sometimes, sometimes not. It would run fine for a while, then stick again when the revs got low (when pin in the regulator was retracted).

As I said, mine was leaking too, through the center of the regulator and back up to the power connector. If it starts happening again I'd say to replace it. They're about €50 on ebay and an easy fix.
 

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Yea, once you move the fuel lines and the injector harness out of the way. You can get away without removing the timing belt cover or the EGR pipe. It's down the back here.



This is it, there's a metal plate around it with three torques, and the regulator itself has three torques itself as well. I had to do most of it by feel but it never took me more than a few seconds to find each bolt.
Mine looks a bit manky as I had an oil leak from the manifold all down the back. Probably want to give the area a clean too before you take it off since you don't want crap getting into the HP fuel line/pump..



I was being a bit too gently with the fuel pipes at the beginning but at the end I was just dragging them out of the way, there's no fear I'd say..

And obviously you need to remove the air filter too, I hate removing the air filter, I've done it about 20 times already! :)
 

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Discussion Starter #14
Spot on jimmy. Thanks. It might still have taken me too long but I'll certainly have a look through the website to see what manuals are in there for future use. That's half the battle. If you don't know the system layout, diagnosis is very difficult.
 

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I'm using the downloaded version of servicebox, it's quite handy but I think it was something like 27GB download.

It's got all the wiring and engine diagrams, repair procedures etc.

The online version is fine, but they want you to pay for all the 'goodies'!

The offline version can be a bit messed up sometimes and it's tricky to get up and running. But I find it handy to have in case I don't have internet.

I almost bought a Haynes manual at the beginning but I'm glad I didn't now. People say there's a lot of stuff missing from them.
 

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Discussion Starter #16
Thank so Joe. At 27GB, it's worth sticking on the old laptop for use as and when needed. I think Hanynes is not too bad for what it is but OEM stuff can only be better.
 
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