A6 BiTdi (CVUA) code: P0087

[FestimX]

Hello!

I have been having some wierd problems with my car since going stage 2. When I have the S-mode on the transmission and do a kickdown etc I can almost feel the car lose power when its nearing 4800rpm and it will give me the code P0087 ( Fuel Rail/System Pressure - Too Low) However, this only happens sometimes. Most of the time the car will pull really well. My tuner has logged the car after countless pulls and he couldn't see anything that had to do with the software. When we logged the car we could se that it would run out of fuel in some logs. HPFP looked fine, no metal parts etc.

Parts changed:
Fuelfilter
Darkside CP4 meteringvalve (It got alot better after changing this metering valve)
Injector seals

The thing that makes it harder to solve is the fact that for example yesterday I was driving my car home and beat on it pretty well and car was doing perfect and strong as hell. After ALOT of pulls I got ready to overtake 2 cars and at like 4800rpm (ish) car got the code P0087 and glowplug light started flashing.

Any advice what it could be? What should i start looking for?

 

[TheStigOnline]

Hello!

I have been having some wierd problems with my car since going stage 2. When I have the S-mode on the transmission and do a kickdown etc I can almost feel the car lose power when its nearing 4800rpm and it will give me the code P0087 ( Fuel Rail/System Pressure - Too Low) However, this only happens sometimes. Most of the time the car will pull really well. My tuner has logged the car after countless pulls and he couldn't see anything that had to do with the software. When we logged the car we could se that it would run out of fuel in some logs. HPFP looked fine, no metal parts etc.

Parts changed:
Fuelfilter
Darkside CP4 meteringvalve (It got alot better after changing this metering valve)
Injector seals

The thing that makes it harder to solve is the fact that for example yesterday I was driving my car home and beat on it pretty well and car was doing perfect and strong as hell. After ALOT of pulls I got ready to overtake 2 cars and at like 4800rpm (ish) car got the code P0087 and glowplug light started flashing.

Any advice what it could be? What should i start looking for?

Currently dealing with the same on another 3.0 V6 (CDUD, mixed grades of diesel over the years and just over 150k mileage) with that flashing light as a warning from the ECM to protect the engine.

Sadly, its a general trouble code and could be triggered by many, many causes:

- https://www.autoblog.com/amp/2016/03/28/p0087-obd-ii-trouble-code-fuel-rail-system-pressure-too-low/


For Audi's specifically, the following is what I've found from the research:

- Clogged fuel filter (common and an easy fix)
- Faulty high pressure fuel pump (HPFP, mostly Bosch CP4's outside of Europe)
- Faulty low pressure fuel pump (in-tank, symptoms usually worse at lower fuel levels)
- Leaks anywhere along the fuel lines (should be obvious to find, but depends where)
- Faulty MAP sensor (few examples)
- Faulty boost pressure sensor (few examples)
- Faulty fuel pressure sensor (rare examples)
- Faulty fuel pump relay and/or fuse (rare examples)
- Injectors (partial blockage, damaged, etc.)
- Gremlins (temp issue, clear fault and retest)

The fixes included the following:

- Cleaning of the fuel system parts (would advise against in-tank additives as freeing debris only makes this type of fault worse, one exception is Dipetane apparently as its hydrocarbon based so not technically an additive but a fuel enhancement solution)

- Replacement of faulty parts (a how long is a piece of string type excise if the root cause of the fault hasn't been identified first, I don't recommend a let's see what this does approach either)


For the case here after eliminating most of the above causes at least three injectors are somewhat blocked with VCDS testing pointing to this and the rest aren't great after physical inspection, they are the Bosch non-serviceable type as well and will probably toss all six while disassembled, plus a fuel rail/pipe around the engine with a micro leak that only presents at higher pressure usage have been identified for replacement so far.

What I'd recommend overall is to have the car checked by a well known/highly recommended garage/engineering repair business that specialises in modern high pressure fuel systems.

There diagnostics maybe more expensive than the average garage but is better than the lets try some parts here and there approach which gets expensive fast.

Also, this flashing warning light is the start of the problem which usually gets progressively worse as the system is put under increasing pressure while the fault is active, best to have it addressed professionally and sooner rather than later

 

[TheStigOnline]

Currently dealing with the same on another 3.0 V6 (CDUD, mixed grades of diesel over the years and just over 150k mileage) with that flashing light as a warning from the ECM to protect the engine.

Sadly, its a general trouble code and could be triggered by many, many causes:

- https://www.autoblog.com/amp/2016/03/28/p0087-obd-ii-trouble-code-fuel-rail-system-pressure-too-low/


For Audi's specifically, the following is what I've found from the research:

- Clogged fuel filter (common and an easy fix)
- Faulty high pressure fuel pump (HPFP, mostly Bosch CP4's outside of Europe)
- Faulty low pressure fuel pump (in-tank, symptoms usually worse at lower fuel levels)
- Leaks anywhere along the fuel lines (should be obvious to find, but depends where)
- Faulty MAP sensor (few examples)
- Faulty boost pressure sensor (few examples)
- Faulty fuel pressure sensor (rare examples)
- Faulty fuel pump relay and/or fuse (rare examples)
- Injectors (partial blockage, damaged, etc.)
- Gremlins (temp issue, clear fault and retest)

The fixes included the following:

- Cleaning of the fuel system parts (would advise against in-tank additives as freeing debris only makes this type of fault worse, one exception is Dipetane apparently as its hydrocarbon based so not technically an additive but a fuel enhancement solution)

- Replacement of faulty parts (a how long is a piece of string type excise if the root cause of the fault hasn't been identified first, I don't recommend a let's see what this does approach either)


For the case here after eliminating most of the above causes at least three injectors are somewhat blocked with VCDS testing pointing to this and the rest aren't great after physical inspection, they are the Bosch non-serviceable type as well and will probably toss all six while disassembled, plus a fuel rail/pipe around the engine with a micro leak that only presents at higher pressure usage have been identified for replacement so far.

What I'd recommend overall is to have the car checked by a well known/highly recommended garage/engineering repair business that specialises in modern high pressure fuel systems.

There diagnostics maybe more expensive than the average garage but is better than the lets try some parts here and there approach which gets expensive fast.

Also, this flashing warning light is the start of the problem which usually gets progressively worse as the system is put under increasing pressure while the fault is active, best to have it addressed professionally and sooner rather than later

After further bench testing, the other three injectors appear to be good it seems and the car I'm working on here is getting off lightly this time around.

Usually never happens, I'm mostly involved after the bad decisions were made and work is massive

 

[FestimX]

After further bench testing, the other three injectors appear to be good it seems and the car I'm working on here is getting off lightly this time around.

Usually never happens, I'm mostly involved after the bad decisions were made and work is massive

Sorry I have forgot to get on this thread. I now know that when I get to 4600rpm it starts coaling alot and in that moment I get the P008700 code. Im starting to think that my injectors are causing this. Just to make it clear. Even though im running dpf off etc I have no smoke what so ever, only black smoke I have is when it gets to 4600rpm and it sort of "falls on its face". I also got an advice to change the fuel preassure regulator but unfortunately the problem is still there.

My injector values however are perfect so I can't get around this problem in anyway.
Values are:
Injector1 -0.05mg
Injector2 0.26 mg
Injector3 -0.07mg
Injector4 0.05mg
Injector5 -0.11mg
Injector6 -0.06mg

 

[TheStigOnline]

Sorry I have forgot to get on this thread. I now know that when I get to 4600rpm it starts coaling alot and in that moment I get the P008700 code. Im starting to think that my injectors are causing this. Just to make it clear. Even though im running dpf off etc I have no smoke what so ever, only black smoke I have is when it gets to 4600rpm and it sort of "falls on its face". I also got an advice to change the fuel preassure regulator but unfortunately the problem is still there.

My injector values however are perfect so I can't get around this problem in anyway.
Values are:
Injector1 -0.05mg
Injector2 0.26 mg
Injector3 -0.07mg
Injector4 0.05mg
Injector5 -0.11mg
Injector6 -0.06mg

Those values suggest the injectors are almost perfect and well within the expected tolerances, I'd keep investigating personally

And thinking about it now, it's possible that it is tripping because the ECM detects out of factory values post-modification

So, whoever done the work should have accounted for that change and adjusted accordingly if necessary

As I said before any parts are changed, a detailed diagnostic by a specialist is highly recommended

 

[FestimX]

Those values suggest the injectors are almost perfect and well within the expected tolerances, I'd keep investigating personally

And thinking about it now, it's possible that it is tripping because the ECM detects out of factory values post-modification

So, whoever done the work should have accounted for that change and adjusted accordingly if necessary

As I said before any parts are changed, a detailed diagnostic by a specialist is highly recommended

Thanks for your answer. Checked with the local companies and they didn't have the correct bosch tools to diagnostic my fuel system. Nearest company that had the tools is like 250km away. However, im personally suspecting that the HPFP is on its way out or the injectors are having some trouble with opening/closing and im losing fuel pressure when it doesn't "close" and therefore I get the code P008700.

I actually have a Hpfp home now but i'd like to investigate if the injectors are also damaged, do you know any symptoms if an injector "stays open" during high rpm?
As long as I stay below 4600rpm the car pulls very good.

(sorry for bad english)

 

[TheStigOnline]

Thanks for your answer. Checked with the local companies and they didn't have the correct bosch tools to diagnostic my fuel system. Nearest company that had the tools is like 250km away. However, im personally suspecting that the HPFP is on its way out or the injectors are having some trouble with opening/closing and im losing fuel pressure when it doesn't "close" and therefore I get the code P008700.

I actually have a Hpfp home now but i'd like to investigate if the injectors are also damaged, do you know any symptoms if an injector "stays open" during high rpm?
As long as I stay below 4600rpm the car pulls very good.

(sorry for bad english)

That's unfortunate and its a long list for open injectors:

- Your symptoms potentially (most likely points to another root cause however)

- Fuel mix is too rich (losing MPG is a dead give away but sometimes its not so obvious)

- White smoke out of the exhaust

- Misfires (popping and banging)

- RPM is intermittently unstable

Also, your trigger for the fault code is on the high pressure side which eliminates a lot but impossible to be sure without accurate diagnostics