Here to help . . .
Join Date: May 2010
Location: United Kingdom
We have assumed EGR issues as playing in this area seemed to have made the issues worse, but it could have been something else all along, although I am sure a new EGR is benifical if the old one had seen better days. It is a common fault after all.
Anyway, lets consider a fuel/fueling issue next.
The basic principle is: you have a lift pump in the tank, fuel lines run to a fuel filter (with water trap etc), fuel then goes into the high pressure pump (belt driven pump on the side of the engine), this keeps the fuel rail at incredibly high pressure to feed the row of injectors, then an electrical signal fires the injectors, basically letting the high pressure fuel into the cylinders directly.
So, lets start at the beginning. Crack a union/joint before the fuel filter and put the ignition on. Fuel should be pumped out - thus proving the lift pump in the tank works (and you have fuel obviously).
Next, check the filter is ok, fuel is coming out of it (not blocked) and no water etc (drain on the bottom normally). Lots of deisel problems are simple fuel filter issues, so worth changing anyway. It is a service item after all.
Now check you have fuel entering the high pressure pump. You never know, you could have a blocked pipe.
Checking the fuel in the fuel rail is common sense, but I won't describe any particular method to ensure I don't get blamed for some numpty taking risks and hurting themselves. But you obviously are mechanically minded, so use common sense and check you have fuel in the rail.
The last thing would be to find a way of testing the fuel rail pressure. HOWEVER, if this was a problem I would have thought the ECU would flag a code via the pressure sensor.
Does it smoke when you try and start the engine?
Did you check if the air path is complete clear and sealed? Did you check the intake flap (like a butterfly valve) fully opens when the ignition is on? Remember, unlike a petrol, the air intake path should be completely free and open on a deisel. A diesel has no throttle body or butterfly valve like a petrol. The valve on JTD deisels are purely for when the engine is off.
Sorry I didn't get a chance to phone you back today. Hectic here as usual.