[phydor]

Hi there guys.I am having some trouble with an AUDI A6 C6 2010 2.7 TDI.
The car started to give this DTC: P0087 Fuel Rail/System pressure  Too low (mechanical malfunction static) after i worked on it in my garage to change the front right abs sensor.
Because the car was immobilised i didn't mind very much about the error.I thought that it appeared because of my battery dying.
On idle, the car ran normally, but as soon as I left the garage, the car started to stutter whenever I was accelerating.
I put ODIS, watched values, realised that at each hard acceleration, the fuel pressure was dropping on rails.
My initial thought was that HPFP was dying but i checked anyway the fuel lines.And now comes my problem.The fuel doesnt't arrive as it should be at the fuel filter.The fuel pump is good, the problem is between the fuel pump and fuel filter.I tried to blow air  through the hose, to check for constrictions, I can't blow any air into it.
I put another hose from the fuel pump to the fuel filter, the diesel arrives at the fuel filter normally but it doesn't pass through the HPFP pump.I think that the regulator on top of HPFP is bad but I can't believe that the car has 2 fuel problems suddenly, unrelated : FUEL LINES and HPFP .
I checked in the Self Study pdf from AUDI A6 brochure from audi for additional systems that are connected to the fuel line departing from the fuel pump but I couldn't find any.I just found a bi metalic preheating valve that has a junction with this fuel line.
Anybody, any ideas?What could be broken here?

[blackTDI]

Hi there guys.I am having some trouble with an AUDI A6 C6 2010 2.7 TDI.
The car started to give this DTC: P0087 Fuel Rail/System pressure  Too low (mechanical malfunction static) after i worked on it in my garage to change the front right abs sensor.
Because the car was immobilised i didn't mind very much about the error.I thought that it appeared because of my battery dying.
On idle, the car ran normally, but as soon as I left the garage, the car started to stutter whenever I was accelerating.
I put ODIS, watched values, realised that at each hard acceleration, the fuel pressure was dropping on rails.
My initial thought was that HPFP was dying but i checked anyway the fuel lines.And now comes my problem.The fuel doesnt't arrive as it should be at the fuel filter.The fuel pump is good, the problem is between the fuel pump and fuel filter.I tried to blow air  through the hose, to check for constrictions, I can't blow any air into it.
I put another hose from the fuel pump to the fuel filter, the diesel arrives at the fuel filter normally but it doesn't pass through the HPFP pump.I think that the regulator on top of HPFP is bad but I can't believe that the car has 2 fuel problems suddenly, unrelated : FUEL LINES and HPFP .
I checked in the Self Study pdf from AUDI A6 brochure from audi for additional systems that are connected to the fuel line departing from the fuel pump but I couldn't find any.I just found a bi metalic preheating valve that has a junction with this fuel line.
Anybody, any ideas?What could be broken here?

did you remove hoses from pump or fuel filter? if yes check if you plugged correctly pump intake in filter and thats no air in the sistem. my mk6 one time after fuel filter replace i inverted intake with injectors drain and car goes normally to 3000rpm then gives me error fuel pressure insufficient........

[phydor]

The second fuel pump was disconnected.But now, after reconnecting it, i get no pressure in rail.
The injectors are not stuck open.I Checked them individually, no leaks.
It seems that all the fuel gets on the return lines, and no pressure is created, don't know why.I'm attaching screenshots of parameters.I have indeed a dpf threshold error but why doesn't the pressure increase in rails? THe only one left is the HP pump.


Is it possible that ECU could route the fuel towards return lines because of the clogged DPF?Does it have some kind of mechanism that prevents engine starting by not creating pressure in rails?
I gotta take the parameters from another 3.0 engine to have an idea what's going wrong in mine.

[blackTDI]

The second fuel pump was disconnected.But now, after reconnecting it, i get no pressure in rail.
The injectors are not stuck open.I Checked them individually, no leaks.
It seems that all the fuel gets on the return lines, and no pressure is created, don't know why.I'm attaching screenshots of parameters.I have indeed a dpf threshold error but why doesn't the pressure increase in rails? THe only one left is the HP pump.


Is it possible that ECU could route the fuel towards return lines because of the clogged DPF?Does it have some kind of mechanism that prevents engine starting by not creating pressure in rails?
I gotta take the parameters from another 3.0 engine to have an idea what's going wrong in mine.

closed injectors=fuel from pump to injectors drain, did you code injectors or touch these things? try to start with semi tightened injectors pipes to drain air and crank several times.

[phydor]

The second fuel pump was disconnected.But now, after reconnecting it, i get no pressure in rail.
The injectors are not stuck open.I Checked them individually, no leaks.
It seems that all the fuel gets on the return lines, and no pressure is created, don't know why.I'm attaching screenshots of parameters.I have indeed a dpf threshold error but why doesn't the pressure increase in rails? THe only one left is the HP pump.


Is it possible that ECU could route the fuel towards return lines because of the clogged DPF?Does it have some kind of mechanism that prevents engine starting by not creating pressure in rails?
I gotta take the parameters from another 3.0 engine to have an idea what's going wrong in mine.

closed injectors=fuel from pump to injectors drain, did you code injectors or touch these things? try to start with semi tightened injectors pipes to drain air and crank several times.

I tried that but the main problem is not getting any pressure in rail.As you saw in pictures, 7 bars or 14 if i restrict the return line from the HP pump.

[blackTDI]

The second fuel pump was disconnected.But now, after reconnecting it, i get no pressure in rail.
The injectors are not stuck open.I Checked them individually, no leaks.
It seems that all the fuel gets on the return lines, and no pressure is created, don't know why.I'm attaching screenshots of parameters.I have indeed a dpf threshold error but why doesn't the pressure increase in rails? THe only one left is the HP pump.


Is it possible that ECU could route the fuel towards return lines because of the clogged DPF?Does it have some kind of mechanism that prevents engine starting by not creating pressure in rails?
I gotta take the parameters from another 3.0 engine to have an idea what's going wrong in mine.

closed injectors=fuel from pump to injectors drain, did you code injectors or touch these things? try to start with semi tightened injectors pipes to drain air and crank several times.

I tried that but the main problem is not getting any pressure in rail.As you saw in pictures, 7 bars or 14 if i restrict the return line from the HP pump.

ok, thats some hysteresis of the valve that reads pressure in rail i think, buddy, are you sure that you have correctly mounted the intake pipe into the filter? did you try to start with diesel starter spray also? imho the problems can be:
1: wrong mount of intake of pump 
2: no fuel in filter because immo locks the low pressure pump and got no fuel delivered.
3: no coded injectors
4: low battery
5: soooome air in the pipes
6: restriction in pump hoses.
7: faulty pump!
8: check relais/switch of low pressure pump, you can hear the pump noise when turn ignition, or with vag.
if dpf is clogged i think that it will allow you to start car and make some forced regeneration no?
apologize for you!

[phydor]

The second fuel pump was disconnected.But now, after reconnecting it, i get no pressure in rail.
The injectors are not stuck open.I Checked them individually, no leaks.
It seems that all the fuel gets on the return lines, and no pressure is created, don't know why.I'm attaching screenshots of parameters.I have indeed a dpf threshold error but why doesn't the pressure increase in rails? THe only one left is the HP pump.


Is it possible that ECU could route the fuel towards return lines because of the clogged DPF?Does it have some kind of mechanism that prevents engine starting by not creating pressure in rails?
I gotta take the parameters from another 3.0 engine to have an idea what's going wrong in mine.

closed injectors=fuel from pump to injectors drain, did you code injectors or touch these things? try to start with semi tightened injectors pipes to drain air and crank several times.

I tried that but the main problem is not getting any pressure in rail.As you saw in pictures, 7 bars or 14 if i restrict the return line from the HP pump.

ok, thats some hysteresis of the valve that reads pressure in rail i think, buddy, are you sure that you have correctly mounted the intake pipe into the filter? did you try to start with diesel starter spray also? imho the problems can be:
1: wrong mount of intake of pump 
2: no fuel in filter because immo locks the low pressure pump and got no fuel delivered.
3: no coded injectors
4: low battery
5: soooome air in the pipes
6: restriction in pump hoses.
7: faulty pump!
8: check relais/switch of low pressure pump, you can hear the pump noise when turn ignition, or with vag.
if dpf is clogged i think that it will allow you to start car and make some forced regeneration no?
apologize for you!

There's plenty of fuel coming to the high pressure pump.The problem is afterwards.All of it is routed to the return lines.My brother checked the whole system and it's properly connected (he s a technician working for Mercedes Benz).
p.S.We used also another car to start it when its battery died.