Audi A4 B8 2011 CAHA engine cranks but doesnt start?

[hussnainh8]

Hello,

If anyone can help me it would be great.. Bought a car at the auction knowing the engine doesn't start and took it into account I have now plugged in my generic diagnostic tool and behold I have received 2 fault codes.

The codes are:

p008700 - Fuel Rail/System Pressure - Too Low
p008800 - Fuel Rail/System Pressure - Too High

I did try my VCDS but I am using a clone copy and it doesnt recognise the modules for the 2011 Audi (Only really bought it for cars under 2007 which it works with them perfectly fine). It didnt recognise the codes but did give me 2 error codes as well which are

5229 - ROD - Unknown Error Code
5212 - ROD - Unknown Error Code

Quick check online also points to something related with the fuel rail pressure being low/high.

Question is.. Where do I go from here? What shall I check first? I am not sure what the previous owner has already tried if they have tried anything so im just going to start from step 1 but what is step 1?

I have located:

Fuel sender
Fuel filter
Fuel pressure sensor
Fuel pressure regulator sensor/valve
Fuel pump
Fuel in tank sender

Dont know which one to replace first... Is there a way to test the fuel pressure sensor, the fuel pressure regulator and fuel pump itself using VCDS?

Any replies will be much appreciated.

Thank you.

[A8Cruiser]

Your best bet, would be to have a look on eBay as there you will find a few VAG-Com bods offering to come round and diagnose for you.
Do that, get the print outs as then you will have the correct codes to work from.

No use working on unknown issues with unknown and out-dated software....

[hussnainh8]

Your best bet, would be to have a look on eBay as there you will find a few VAG-Com bods offering to come round and diagnose for you.
Do that, get the print outs as then you will have the correct codes to work from.

No use working on unknown issues with unknown and out-dated software....

Will VCDS tell me exactly which part is causing the fault? I thought the generic reader codes p008700 and p008800 is the same thing VCDS would tell me?

Thank for the reply.

[A8Cruiser]

Probably not.
But the newer software will be set up to read and diagnose the car properly.

Afterall, you wouldn’t run Windows XP on an Intel i7. You wouldn’t get the best out of it.

[hussnainh8]

Probably not.
But the newer software will be set up to read and diagnose the car properly.

Afterall, you wouldn’t run Windows XP on an Intel i7. You wouldn’t get the best out of it.

Okay im going to renew my VCDS license and see what it can tell me differently to WOW diagnostics. On WOW I was able to turn the fuel pump relay on and heard the motor humming but no way to test the sensors so maybe on VCDS I can test the sensors some how.

[hussnainh8]

Okay im going to renew my VCDS license and see what it can tell me differently to WOW diagnostics. On WOW I was able to turn the fuel pump relay on and heard the motor humming but no way to test the sensors so maybe on VCDS I can test the sensors some how.

Tried with VCDS and no codes showed up in the engine module as well as the auto scan. That might have something to do with me erasing the codes from the previous software I used which erased fine and didnt show up there as well. Could they be old codes then as they have not come back on again? The car battery went under 12v so now I have left it charging overnight and hopefully tomorrow I will try to check the codes again. Bit puzzled that its not showing anything now...

Thanks.

[A8Cruiser]

YEah, I think you would need to try starting agin to get the codes to re-appear.
The battery will need around 13 volts or so? These things are power hungry to start.


You can also have a look at this site. Audi Parts catalog - ETKA Online, Audi EUROPA, original Catalog Audi EUROPA
It is the ETKA (Audi parts) site. Online version.

[hussnainh8]

YEah, I think you would need to try starting agin to get the codes to re-appear.
The battery will need around 13 volts or so? These things are power hungry to start.


You can also have a look at this site. Audi Parts catalog - ETKA Online, Audi EUROPA, original Catalog Audi EUROPA
It is the ETKA (Audi parts) site. Online version.

So a little update on this.... Charged the battery tried cranking, no engine light no codes. I then used VCDS to test the fuel pump/sender under the car floor next to the filter which seems to be working fine so everything is good there. I then searched online more information about the signs and noticed an indian guy on youtube showing a video of his pump saying if you take the fuel regulator of the hpfp, you can see aluminium shards in the hpfp which cause low fuel pressure and the hpfp itself is what causes the low pressure codes on vcds. I then decided okay nothing to loose and took the valve regulator off the hpfp and low and behold saw aluminium shavings in the hole. I have now given the car to a mechanic to replace the hpfp for me as it seems the timing belt needs to come off to replace the hpfp. I did tell the mechanic dont take my word for it as it may not be the hpfp so make sure you do your own checks first before you replace anything as I will only pay you ones you have fixed the car (i.e it starts and drives).

Hes charging a labour off £200 for the fuel pump replacement so it cant work out too much money.

End of the day I already know how to do the fuel filter, fuel lines, injectors or fuel sender. Its just I would not rather mess about with the hpfp itself if it runs of the timing belt. Not worth taking the risk for 200quid. So fingers crossed, I get a call tomorrow and the issue is fixed.

Thank you for your time.

[Refrigerator]

Sorry to poke such an old thread, but was wondering if you did manage to fix the issue in the end?
Unfortunately I'm having the exact same issues (Fuel Rail/System Pressure - Too Low) but have not looked into the fuel regulator to see if there are any metal shards as I don't have the car at my current location.

Thank you

[hussnainh8]

It was the fuel pump on this so new pump fixed it