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[irpearce]

1995 2.5 TD. I've just tried to seal the two gaskets in the fuel metering unit due to a leak but cannot re start the engine.
I can hear the fuel pump running when ignition on (for about 10 secs) and there is fuel at the bleed screw on the fuel unit.
I have removed the fuel pipes at the injectors but no fuel is coming through with either pump running or when cranking.
There is fuel at the very front leakoff pipe when the pump runs.
I don't know enough about how this is meant to work.
Should fuel be at the injectors with just the pump running, or do you need to be cranking?
Could I have reassembled the unit wrongly - it seemed simple enough. When tightening down I wasn't sure how to position the unit on the slotted screws - is this important?
It seems like the fuel pump isn't strong enough to lift the fuel but it always worked before. The flow at the bleed screw and leakoff pipe is only moderate
Any help/advice would be appreciated.

[tigers_gonads]

Air lock somewhere 

[TheBoy]

Correct way to bleed these is:

Ensure the fuel filter is full of diesel.
While cranking, in turn, loosen the nut securing the metal fuel pipe to the top of each injector, until fuel spurts upwards, retighten, then move on to next injector.

Obviously, only short bursts of cranking, else you'll knacker the starter.

[Marks DTM Calib]

No fuel will get ot the injectors unless the engine is cranking.

[irpearce]

Still no joy. Have removed manifold again and removed all 6 glowplugs to ensure max cranking speed. The injector pump is bled and flow from fuel tank pump is fine.
But still no fuel at injectors after loads of cranking. No apparent leaks from the injector pump.
I'm missing something here. What else can I check? Help anybody!!

[tigers_gonads]

Can you rig up some sort of test lamp across the injector plug to see if you are getting a 12 volt pulse ?
Or a old style test meter with a needle ?
A modern digital type might not react fast enough to see 

Maybe remove a injector, leave it plugged in and crank it over to see if it is working.

[irpearce]

Can you rig up some sort of test lamp across the injector plug to see if you are getting a 12 volt pulse ?
Or a old style test meter with a needle ?
These are mechanical injectors relying on a fuel pulse from the injection pump not the modern electrical type

Maybe remove a injector, leave it plugged in and crank it over to see if it is working.
No fuel is even getting to the injectors so the problem is with the injection pump

Could the problem be the stop solenoid - anybody know anything about this?

[TheBoy]

Did you bleed as I suggested above?

[irpearce]

Did you bleed as I suggested above?

Yes but didn't work.

Tried opening a couple of the high pressure pipe unions at the back of the injection pump - no fuel when cranking
Checked the shut off solenoid which seems to work fine.
Tried without the shut off solenoid pin (ie always open) - no fuel when cranking
So whatever I do there's no fuel coming out of the injector pump (flow in from the tank pump is fine)
I even checked that the chain drive from the camshaft is OK

It seems that the pump is either not pressurizing the fuel or not distributing it to the high pressure pipes. What could cause this?

It worked fine (but leaked) before I opened it up to seal the leak. There doesn't seem much to get wrong (!!!!!) doing this but I clearly have cocked something up. The only () variable is the rotary potentiometer.
The resting position can be varied by how you position the bolts on the slotted holes in the body. I've tried a couple of different positions but it changes nothing.

Any more thoughts?

[hoofing it]

Judging by your post you have been tampering with the main injector pump but what seals are you talking about is it the one in the link below.
http://www.omegaowners.com/forum/index.php?topic=90655.0
Also have you put a live feed direct from the battery to the fuel pump solinoid and listen for it clicking mind only touch the top threaded bit.(Its in the first picture on the above link)
The only thing that will stop fuel getting to the injectors is the fuel pump solinoid thats what allows the engine to start/stop
What part of the country are you in maybe a mobile mechanic here on oof might be able to help

[irpearce]

I have seen those pics. I got them via this thread
Leaking injector pump 2.5tdi 6cyl diesel
16. Jun 2011 at 23:23
The seals are the the ones above and below the section in pic 4.
Yes, have tested the pump solenoid. It works OK.
It should pump fuel - but it doesn't.
I'm missing something somewhere.
Bit concerned about the correct location of the quantity control servo arm in the control spool on re-assembly. Another post I found mentioned that this is diffficult but it seemed straightforward. I'm on Devon/Cornwall border. Problem is - every time I spend a fiver it doubles the value of my faithful old 239k miler!

[Omegatoy]

rough guess is you havent put the fbw throttle plate in the correct postion,and it dont know that the throttle is opening,time to take the top off agin methinks 

[irpearce]

Thanks for all help. Think Omegatoy is on the right track.
I found this brilliant pdf which explains exactly how this works

http://www.dieselbookmarks.com/bombers/VEPump.pdf

Our pump is on p45.

I think I have it assembled right but it seems that the control spool is not covering the injection relief port meaning no pressure to outlet pipes. Seems the poteniometer isn't working/getting a signal. It was working before - perhaps I disturbed a wire. Will investigate tomorrow

[irpearce]

Running again. The problem was all about the position of the top part of the body (which I had removed to reseal the leaking gasket) on the four slotted location holes. This in turn affects the position of the control spool. I had clamped it up too far towards the front of the engine which meant the the contol spool was not far enough over the pressure relief hole so no pressure to injectors. Slide it backward a bit and you get fuel to the injectors for bleeding but not enough pressure to activate them properly. Slide it right to the back and the hole is completely covered and the car starts immediately and shoots to max revs. So the right position is somewhere inbetween. It is a VERY FINE adjustment - it took me eight attempts and then suddenly a perfect tickover and all is well.
Lessons to learn and to help anybody else who has to reseal a leaking pump
Understand how the thing works (see link in previous post)
Carefully mark the position of the upper body on the slots before removal
Even then the adjustment is critical
Never give up

It's a love /hate thing  but it's one hell of an engine! Onwards to 250K
Thanks again for all the help

[Omegatoy]

Good news dude!! sorry meant to post to say if you get it to far one way it revs its nuts off, but couldnt remember which was which and didnt want to give you bum info hence i posted the link to the pump!!