V9X Air in Fuel

[Andyjo]

Hi all, does anybody have experience with air entering the fuel system on a V9X motor? Problem is between the filter and HP fuel pump. No sign of any fuel leak on the tangle of fuel lines, I pressured up the lines, still no sign of leaks. Put clear plastic pipe on return line from pump to tank and gravity fed fuel into the filter (clear plastic line). No air in the line to the filter but can see spritzes of air sporadically in the return line. Can air enter anywhere in the pump? Has anybody rebuilt the bosch radial piston pump? Can I get a seal kit for the pump? New pump is $1000+!! I'm assuming that it is a pump issue?
Positive pressure fuel feed to pump reduces the problem but if the pump has to lift the fuel from the tank fuel air contamination is worse. I'm considering installing a 12v lift pump near the tank, any body have experience with that exercise?

 

[Old.Tony]

If you've pressurised the fuel lines so that there are no signs of leaks between the fuel tank and the pump, then the air is in the pump and it has to be bled properly.

There's a process to it, you need to open the bleed valve on the pump and use the primer to push fuel into the pump and let the air out.

 

[Andyjo]

Old Tony, thx for your input. Ive bled the system with the bleeder pump numerous times and still have air coming out of the system, so I doubt it is residual trapped air. I'm leaning toward an air leak on the injector spill and fuel return lines. The v9x motor has a cold start fuel recirculation circuit that channels the return fuel back into the pump main fuel supply via the "fuel return control valve" (FRCV). I can't find any info on how the valve works but it diverts the return fuel back into the pump. Once warm the frcv diverts all the fuel to the return. I'm going to isolate that recirculation circuit to see if that solves the problem.
I'm pretty sure my problem is air entering the fuel system, just gotta find out where and how. Do you know how the frcv works? Is it similar to a thermostat? The is no wiring on it.
Any thoughts or suggestions?

 

[Old.Tony]

I can't think of what would introduce more air in at that point, I'm at the limit of my experience with it. I can only hope someone else with a V9X can come along and offer some help.

 

[Andyjo]

Does anybody know where I can get detailed information on the bosch high pressure fuel pump? Best I've found so far is a rather poor exploded view. I'd like to see how the pump works and if there is any possibility that it can introduce air into the fuel system.

 

[Nicolas972]

Hi all, does anybody have experience with air entering the fuel system on a V9X motor? Problem is between the filter and HP fuel pump. No sign of any fuel leak on the tangle of fuel lines, I pressured up the lines, still no sign of leaks. Put clear plastic pipe on return line from pump to tank and gravity fed fuel into the filter (clear plastic line). No air in the line to the filter but can see spritzes of air sporadically in the return line. Can air enter anywhere in the pump? Has anybody rebuilt the bosch radial piston pump? Can I get a seal kit for the pump? New pump is $1000+!! I'm assuming that it is a pump issue?
Positive pressure fuel feed to pump reduces the problem but if the pump has to lift the fuel from the tank fuel air contamination is worse. I'm considering installing a 12v lift pump near the tank, any body have experience with that exercise?

Hello
same trouble than yours …. still looking for a solution !!!!!!

At this point and after several forum research , here are what I have found
- injection pump failure
- return hose from the injectors ( not sure because I maybe should have fuel leaking) around it !!!)
- EGR trouble ( already changed two times )

 

[Olpha]

I will have another look at the notes I have written regarding the shut off system for these motors but I seem to remember there is a solenoid that opens when you turn the key off which drops the injector fuel pressure supply. Perhaps there is air leaking back through the lines and enter that system which would in turn get back into the pump when you start cranking.
I would very much doubt that it is a high pressure pump failure as these are usually sudden and catastrophic. ie the ******* stops dead in its tracks.
It may also be pertinent to check the wiring leading to that shut off valve as a simple break or poor connection could wreak havoc
I will do some more reading up tonight and post anything of help that I can

 

[Nicolas972]

Where is this solenoid ?

 

[Nicolas972]

Today after re-primed the engine start ,difficult after one week but as usual nothing wrong when the engine is started idle ok etc
After 30 minutes The thing I have notice was an big white smoke from the exhaust, during one minute and disappear
After that the engine what’s still ok for 30 min and I turn it of
Today the car is going on a tow truck to a diesel specialist

 

[Old.Tony]

It sounds like it's trying to do a DPF regen.

 

[Olpha]

If this is in Aus then there is no DPF fitted to the v9x so it does sound more like air or the old oil build up in the intake suddenly going through the engine trick.
In regard to the solenoid, it is at the rear of the bank 2 or left bank pressure rail. It holds a constant pressure of about 150psi in the injector. My understanding is that the purpose is to allow the injector to hold higher rail pressures and allow smooth injection. Therefore if this solenoid starts to fail for any reason I expect you may well see some unusual shutdown situations. Is there a fault code? I haven't got that far yet