2.1 TD suspected major air leak but not sure where!

[red_dwarfers]

I've got a Bosch injected 2.1 TD 605 which has been having running issues. The problem quite literally happened overnight.
It idles okay but won't rev above 2000/2500rpm even with the throttle lever pulled back all the way.
It hesitates a lot while revving.
There is excessive black smoke coming out the exhaust.
If I press the priming bulb the engine settles down and will rev properly.

I've done the following with no change:
Container of diesel to clear pipe, priming bulb, clear pipe, in to the pump inlet to rule out the fuel pipes. No bubbles in the clear pipe.
Loosened the injectors, turned the engine over to bleed any air out.
Changed the leak off pipes.
Replaced the seals mentioned in Jims guide including the distributor head seal.

While I had the pump off I changed the timing belt, water pump, tensioners then triple checked the timing.

I'm at a bit of a loss now!

Any ideas?

[evilally]

Wouldn't lots of black smoke indicate insufficient air, not fuel? Have you checked all of the intake pipework?

[Northern_Mike]

There is excessive black smoke coming out the exhaust.


Any ideas?

To me, that indicates a lack of air rather than too much fuel Kev. Check the intake pipework. You've not left a rag somewhere you shouldn't have you? (I once did this with a Skoda Estelle inlet manifold while I had the carb off)

[citronut]

you didnt park it tooooo close to that XM did you

do these suffer probs with a fuel return leak, like leak off pipes split????

[red_dwarfers]

I forgot to mention that, I've run the car with the top part of the inlet manifold removed temporarily and it still won't rev properly.

I'm tempted to replace the leak of pipes again just in case.

I've had a couple of other suggestions, lift pump in the injection pump not working to full capacity or maybe the injectors aren't firing out a decent spray. Not sure how adding fuel pressure from the priming bulb would help the injectors mind.