Technical No diesel flow past high pressure fuel pump

[Chandler garnett]

I have recently swapped a engine on a mk2 fiat doblo 2.0l and have run into a crank no start issue. I have fuel supply to the pump and can see on my scanner it reaches 250 bar but drops off instantly. There is also no flow on the diesel lines and current no injector pulse but that is probably cased by non stable fuel pressure

 

[bugsymike]

I have recently swapped a engine on a mk2 fiat doblo 2.0l and have run into a crank no start issue. I have fuel supply to the pump and can see on my scanner it reaches 250 bar but drops off instantly. There is also no flow on the diesel lines and current no injector pulse but that is probably cased by non stable fuel pressure

If it is not one of the fuel sensor/regulator controls at pump or on Common rail, is it possible you have a faulty injector as one duff one will be enough.
It may be worth trying a "leak of" test.

 

[Chandler garnett]

If it is not one of the fuel sensor/regulator controls at pump or on Common rail, is it possible you have a faulty injector as one duff one will be enough.
It may be worth trying a "leak of" test.

I think it could be the regulator as there is no fuel even getting to the injectors. The rail sensor works and cam sensor so not sure what else it could be

 

[bugsymike]

I think it could be the regulator as there is no fuel even getting to the injectors. The rail sensor works and cam sensor so not sure what else it could be

So with a pipe off the common rail no fuel is dribbling out?
I know what you mean re the regulator, I have seen a clip of an American testing with pipes to see what his was doing and it showed fuel going directly to the return.
However recently we had one on a 1.3MJ which in the end was a faulty injector.
If you have been trying for a bit and it was an injector presumably it will have dribbled into the engine oil.
Either way a "leak off" test just using similar size plastic bottles and some screen wash hose may help to eliminate that as a cause.
I did by a set of injector blanks for testing , but have never got around to needing them.

 

[Chandler garnett]

So with a pipe off the common rail no fuel is dribbling out?
I know what you mean re the regulator, I have seen a clip of an American testing with pipes to see what his was doing and it showed fuel going directly to the return.
However recently we had one on a 1.3MJ which in the end was a faulty injector.
If you have been trying for a bit and it was an injector presumably it will have dribbled into the engine oil.
Either way a "leak off" test just using similar size plastic bottles and some screen wash hose may help to eliminate that as a cause.
I did by a set of injector blanks for testing , but have never got around to needing them.

Yeh not much is dripping out the fuel rail I have tried to vacuum bleed the rail through the injectors but seems like some is stopping flow past the pump. I have checked the fuel in the pump and that seems fine so it must be a faulty regulator or a sensor that's stopping the regulator from opening

 

[bugsymike]

Yeh not much is dripping out the fuel rail I have tried to vacuum bleed the rail through the injectors but seems like some is stopping flow past the pump. I have checked the fuel in the pump and that seems fine so it must be a faulty regulator or a sensor that's stopping the regulator from opening

You will not get a flow from common rail unions and when systen is working it will self bleed completely dur to extremly high pressures, so keep fingers away from what may look like a little mist from a high pressure union.
Modern injectors work at something like 2000Bar max, as an apprentice in 1969 the instructor showed a piece of A4 paper and then held it in front of an injector spray and we could see it had punched holes in the paper, that was with 175 Bar pressure, not 2000Bar! People try to bleed a modern Common rail system, but even one union open a little will stop an engine.
So basically all assembled and tight with a good supply to the high pressure pump and then after a few cranks it should fire up.
I would still try the "leak off test".