Audi 8p 2.0t quattro low fuel pressure and stalling

[A4dtmwanted]

Hi all , I have used the search function but not had any joy.
I have a audi a3 8p 2.0t quattro stage 2.
Recently I have had a stalling issue.
Fault p310c low fuel pressure.

The car will cut out and then not start, 10 to 15 min later it starts.

I have changed in tank fuel pump but still no joy.

Anyone had similar issue, I was go8ng for hpfp next as the sensor on top has a hairline crack in it.

However my s3 has a crack in the same sensor and works fine.

Not sure where to start now any help would be appreciated.


Cheers
ASH

 

[Davill9]

I had same issues but different code I think,
it was hpfp.
bought a loba one for new map and never had an issue again.
Easy to tell by doing a few checks
Pulling fuse, vagcom and crimping the feed hose etc.
the usual stuff

 

[A4dtmwanted]

I had same issues but different code I think,
it was hpfp.
bought a loba one for new map and never had an issue again.
Easy to tell by doing a few checks
Pulling fuse, vagcom and crimping the feed hose etc.
the usual stuff

Thanks for the reply pal.
Not being funny can you tell me what checks to do etc and how.
My friend has vcds so he can help with that.
Just need to find what parameters items should be!
Tbh I have had it stage 2 for 6 years no issue now its the first time it's gone wrong.
I happy to buy a hpfp but not sure how to test it.
Would rather diagnose it before i change random parts.!
Any help would be appreciated.

 

[Davill9]

Thanks for the reply pal.
Not being funny can you tell me what checks to do etc and how.
My friend has vcds so he can help with that.
Just need to find what parameters items should be!
Tbh I have had it stage 2 for 6 years no issue now its the first time it's gone wrong.
I happy to buy a hpfp but not sure how to test it.
Would rather diagnose it before i change random parts.!
Any help would be appreciated.

I can explain better when I have a bit more time as am sorting out an issue on an r8 fuelling issue today but to get you going matey…

I will try and find a proper description as I’m not the best at explaining, I just do it if u know what I mean. Explanations are new to me so bear with….


so first one is vagcom
Engine
Mvb 103
This shows the low fuel pressure side reading
Start the car and find the fuel feed
Should be I think about 6-7 bar if I remember right
Use brake line pliers to pinch feed. Within a few seconds it should drop down to about 5 then down to 3 until it probably stalls
So you know that most likely the in tank pump is working on tick over and the low pressure fuel sensor is working.
I have seen these drop fuelling before and stay at a reading of 7. That’s the low side sensor
A low reading before pinching is weak pump
And check first the ignition not started pressure too to see what it builds up to before cranking when cold.


Next is
Engine
Mvb 002 coolant temp
This is to check engine is up to operational temperature about 90c I think
Then engine
Mvb 106 high fuel pressure
So you get to temp and see on tickover
What it is saying as reading
Turn car off.
watch the fuel pressure.
it should climb as the car starts to turn into a heat sink and warm the hpfp up
This should make the pressure continuously climb- on a hot day it can take about 6mins and get to release valve pressure of 133psi or something like that and you will actually hear it in the car like a wet fart sound releasing the fuel back
That’ll tell you release valve is working properly
What you are looking for here though more if I remember right is a rise constantly maybe slowly but constant climb in pressure for at least 2/3 mins

then the hpfp is holding pressure.





next
Engine
Mvb 230 commanded & actual fuel pressure

Now you are more familiar with your fuel pressures, this will show what the car is commanding and what it is getting
I imagine that with a map it will be slightly up and down but not by much but you can see the difference between the two
Tick over and on driving this is. So go for a run and I always found it easier to do a video on phone of the drive when I start the live recording log so any drops etc I can see when it happened as it may have been changing gears onto motorway or heavy braking for example
Just easier to match the two up when back and looking at results

from memory, I think the above low pressure one also has commanded and actual so that is maybe another check too

then there is fuel trims…
I think I did a post on fuel trims in the past but can explain them in detail later on as it’s not just a do this and that and it’s there. Took me a while to understand that in training - a rabbit hole tfs.

if you wanted to look
Engine
Mvb 032,-033 fuel trim
But bear in mind every engine fault clear or 3 in a row in under 30secs clears fuel trims to 0.0 again on idle and partial throttle so bear that in mind also.

another is
Engine
Mvb 014-016 misfire
May show something too maybe not relevant to this but handy to check when doing live driving log at same time I think.

hope it gives you a start and don’t quote me 100% as it’s a while since I have used those measuring value blocks so they may be either side by 1or2
Good luck mate

 

[A4dtmwanted]

I can explain better when I have a bit more time as am sorting out an issue on an r8 fuelling issue today but to get you going matey…

I will try and find a proper description as I’m not the best at explaining, I just do it if u know what I mean. Explanations are new to me so bear with….


so first one is vagcom
Engine
Mvb 103
This shows the low fuel pressure side reading
Start the car and find the fuel feed
Should be I think about 6-7 bar if I remember right
Use brake line pliers to pinch feed. Within a few seconds it should drop down to about 5 then down to 3 until it probably stalls
So you know that most likely the in tank pump is working on tick over and the low pressure fuel sensor is working.
I have seen these drop fuelling before and stay at a reading of 7. That’s the low side sensor
A low reading before pinching is weak pump
And check first the ignition not started pressure too to see what it builds up to before cranking when cold.


Next is
Engine
Mvb 002 coolant temp
This is to check engine is up to operational temperature about 90c I think
Then engine
Mvb 106 high fuel pressure
So you get to temp and see on tickover
What it is saying as reading
Turn car off.
watch the fuel pressure.
it should climb as the car starts to turn into a heat sink and warm the hpfp up
This should make the pressure continuously climb- on a hot day it can take about 6mins and get to release valve pressure of 133psi or something like that and you will actually hear it in the car like a wet fart sound releasing the fuel back
That’ll tell you release valve is working properly
What you are looking for here though more if I remember right is a rise constantly maybe slowly but constant climb in pressure for at least 2/3 mins

then the hpfp is holding pressure.





next
Engine
Mvb 230 commanded & actual fuel pressure

Now you are more familiar with your fuel pressures, this will show what the car is commanding and what it is getting
I imagine that with a map it will be slightly up and down but not by much but you can see the difference between the two
Tick over and on driving this is. So go for a run and I always found it easier to do a video on phone of the drive when I start the live recording log so any drops etc I can see when it happened as it may have been changing gears onto motorway or heavy braking for example
Just easier to match the two up when back and looking at results

from memory, I think the above low pressure one also has commanded and actual so that is maybe another check too

then there is fuel trims…
I think I did a post on fuel trims in the past but can explain them in detail later on as it’s not just a do this and that and it’s there. Took me a while to understand that in training - a rabbit hole tfs.

if you wanted to look
Engine
Mvb 032,-033 fuel trim
But bear in mind every engine fault clear or 3 in a row in under 30secs clears fuel trims to 0.0 again on idle and partial throttle so bear that in mind also.

another is
Engine
Mvb 014-016 misfire
May show something too maybe not relevant to this but handy to check when doing live driving log at same time I think.

hope it gives you a start and don’t quote me 100% as it’s a while since I have used those measuring value blocks so they may be either side by 1or2
Good luck mate

Cheers mate thanks very much for that info I appreciate it, now at least i have something to look into. Its hard to find what values etc things should be running at. I will have a go and let you know how I get on.
Shame you dont live near manchester i would have popped over to see you!

 

[A4dtmwanted]

I can explain better when I have a bit more time as am sorting out an issue on an r8 fuelling issue today but to get you going matey…

I will try and find a proper description as I’m not the best at explaining, I just do it if u know what I mean. Explanations are new to me so bear with….


so first one is vagcom
Engine
Mvb 103
This shows the low fuel pressure side reading
Start the car and find the fuel feed
Should be I think about 6-7 bar if I remember right
Use brake line pliers to pinch feed. Within a few seconds it should drop down to about 5 then down to 3 until it probably stalls
So you know that most likely the in tank pump is working on tick over and the low pressure fuel sensor is working.
I have seen these drop fuelling before and stay at a reading of 7. That’s the low side sensor
A low reading before pinching is weak pump
And check first the ignition not started pressure too to see what it builds up to before cranking when cold.


Next is
Engine
Mvb 002 coolant temp
This is to check engine is up to operational temperature about 90c I think
Then engine
Mvb 106 high fuel pressure
So you get to temp and see on tickover
What it is saying as reading
Turn car off.
watch the fuel pressure.
it should climb as the car starts to turn into a heat sink and warm the hpfp up
This should make the pressure continuously climb- on a hot day it can take about 6mins and get to release valve pressure of 133psi or something like that and you will actually hear it in the car like a wet fart sound releasing the fuel back
That’ll tell you release valve is working properly
What you are looking for here though more if I remember right is a rise constantly maybe slowly but constant climb in pressure for at least 2/3 mins

then the hpfp is holding pressure.





next
Engine
Mvb 230 commanded & actual fuel pressure

Now you are more familiar with your fuel pressures, this will show what the car is commanding and what it is getting
I imagine that with a map it will be slightly up and down but not by much but you can see the difference between the two
Tick over and on driving this is. So go for a run and I always found it easier to do a video on phone of the drive when I start the live recording log so any drops etc I can see when it happened as it may have been changing gears onto motorway or heavy braking for example
Just easier to match the two up when back and looking at results

from memory, I think the above low pressure one also has commanded and actual so that is maybe another check too

then there is fuel trims…
I think I did a post on fuel trims in the past but can explain them in detail later on as it’s not just a do this and that and it’s there. Took me a while to understand that in training - a rabbit hole tfs.

if you wanted to look
Engine
Mvb 032,-033 fuel trim
But bear in mind every engine fault clear or 3 in a row in under 30secs clears fuel trims to 0.0 again on idle and partial throttle so bear that in mind also.

another is
Engine
Mvb 014-016 misfire
May show something too maybe not relevant to this but handy to check when doing live driving log at same time I think.

hope it gives you a start and don’t quote me 100% as it’s a while since I have used those measuring value blocks so they may be either side by 1or2
Good luck mate

Cheers mate thanks very much for that info I appreciate it, now at least i have something to look into. Its hard to find what values etc things should be running at.I will have a go and let you know how I get on.
Shame you dont live near manchester i would have popped over to see you!

 

[Davill9]

Cheers mate thanks very much for that info I appreciate it, now at least i have something to look into. Its hard to find what values etc things should be running at. I will have a go and let you know how I get on.
Shame you dont live near manchester i would have popped over to see you!

Sorry it was rushed, I was in the queue at tps with a spare 5 mins
It is a shame more so as I think I have a few standard hpfp here for the tfsi somewhere

Also let me know if you do end up changing hpfp as there is a quick way to swap… with a bit of mechanical knowledge it can be done in 5-10 mins
Annoyingly I am up in gunchester soon to see unicorn Rick to do my stage 3 mapping - but once car is all back together so a month or two I’m guessing as being that good at what he does, it’s not surprising he’s always in high demand .

also point to note .. my car was unicorn stage 1 - everyone else stage 2 equivalent. 340hp on high boost 310hp low boost maps.
standard pump worked for about 4 years fine also but the car did hardly any miles tbf.
Sent from my iPhone using Tapatalk

 

[A4dtmwanted]

Sorry it was rushed, I was in the queue at tps with a spare 5 mins
It is a shame more so as I think I have a few standard hpfp here for the tfsi somewhere

Also let me know if you do end up changing hpfp as there is a quick way to swap… with a bit of mechanical knowledge it can be done in 5-10 mins
Annoyingly I am up in gunchester soon to see unicorn Rick to do my stage 3 mapping - but once car is all back together so a month or two I’m guessing as being that good at what he does, it’s not surprising he’s always in high demand .

also point to note .. my car was unicorn stage 1 - everyone else stage 2 equivalent. 340hp on high boost 310hp low boost maps.
standard pump worked for about 4 years fine also but the car did hardly any miles tbf.
Sent from my iPhone using Tapatalk

I may have to see Rick too to get a better map.
We have tested what we can and all seems to be well.
However when he disconnected the hpfp the car still stayed started is that right I assumed it would turn off?
Also I heard a buzzing noise the other day before it stalled. Maybe a relay.
Do you know where the fuel pump relays are located.
May have to change the hpfp aswell as cant seem to find the issue.
What was the quick guide?

Cheers

 

[A4dtmwanted]

Hi does anyone have any ideas.
I have now chnage lpfp, fuel lump model, cam follower,thrust sensor and still no joy?running out of ideas and funds at this rate. Next option is to try a new hpfp?

 

[Davill9]

How did you get on with the heat sink pressure build up test for hpfp on vag com?
I would probably say it was your issue even if the pressure was holding as they are well known to be knackered when cracked.
Side point- I know AMD have in the past changed just the pressure switch on the top and not the whole hpfp if they hold pressure and don’t leak fuel into crank case/ oil through the cam follower section

I asked my mate that works there while one was being done and they are apparently about 50-60 quid to buy and there is a procedure to do to remove and re fit without damage to pump but it’s just the plug off and undo the large nut on top

 

[A4dtmwanted]

How did you get on with the heat sink pressure build up test for hpfp on vag com?
I would probably say it was your issue even if the pressure was holding as they are well known to be knackered when cracked.
Side point- I know amd change just the pressure switch on the top and not the whole hpfp if they hold pressure and don’t leak fuel into crank case/ oil through the cam follower section

I asked my mate that works there and they are apparently about 50-60 quid to buy and there is a procedure to do to remove and re fit without damage to pump but it’s just the plug off and undo the large nut on top

When he tested it , he said it held pressure I wasn't there due to my son being ill!

That great , do you know where or how I can get the sensor. Audi only sell it as a complete unit.
It's the crack in sensor that's making me think it may be that!

 

[Davill9]

Yeah I was at that point back a while ago about to do before the loba one came into my possession - nearly new - came with a timing chain cover he purchased and I replaced for a mate and he gave me the pump for me doing the timing cover for him

ill try and have a look for where they were from for you
I think they were called pressure switch high pressure or something like that

 

[A4dtmwanted]

Yeah I was at that point back a while ago about to do before the loba one came into my possession - nearly new - came with a timing chain cover he purchased and I replaced for a mate and he gave me the pump for me doing the timing cover for him

ill try and have a look for where they were from for you
I think they were called pressure switch high pressure or something like that

Great thanks for checking for me.
Is it the sensor that fails or the actual pump.
Trying to ge hold of unicorn to check the fault but can't get through to them.
Hopefully it will be the hpfp.

 

[Davill9]

That’s what the pressure test I said to do in vcds was -to see If it was holding pressure ( hpf side under heat sink of engine when turned off, after reaching operational temp should rise and rise as I said before.
Both options could potentially fall but usually you get very petrol smelling oil if leaking to crank case.
As there is a crack on the hpfp sender, this is a well known and documented thing, they fall when cracking or crack when failing… whichever way round it is. (Not sure)

i think Rick is fully booked for over a year atm
And only dealing with previous existing customers.
I don’t think they are talking any new jobs on at present.

I think probably best to run full vcds scan and post the whole thing on here as I guess a lot of other members will not read the scan you previously posted as not vagcom you see.

 

[A4dtmwanted]

That’s what the pressure test I said to do in vcds was -to see If it was holding pressure ( hpf side under heat sink of engine when turned off, after reaching operational temp should rise and rise as I said before.
Both options could potentially fall but usually you get very petrol smelling oil if leaking to crank case.
As there is a crack on the hpfp sender, this is a well known and documented thing, they fall when cracking or crack when failing… whichever way round it is. (Not sure)

i think Rick is fully booked for over a year atm
And only dealing with previous existing customers.
I don’t think they are talking any new jobs on at present.

I think probably best to run full vcds scan and post the whole thing on here as I guess a lot of other members will not read the scan you previously posted as not vagcom you see.

Cheers I know they not doing remaps for the 8p anymore. Only existing customers as you said.
They gave me someone's number to donthe checks , he supposedly builds their hpfps etc.
So il give him a go and get it scanned and post the results on here.
May have to invest in vcds as ilmbee keeping the car , just dint ever have use for it as its never gone wrong.

 

[Davill9]

Cheers I know they not doing remaps for the 8p anymore. Only existing customers as you said.
They gave me someone's number to donthe checks , he supposedly builds their hpfps etc.
So il give him a go and get it scanned and post the results on here.
May have to invest in vcds as ilmbee keeping the car , just dint ever have use for it as its never gone wrong.

Nice… unicorn is brilliant and if they recommend someone- I’d definitely use them 100%

I thought your guy did the checks on vagcom for you for pressure drop etc… that’s the one I was talking about posting on here mate
It is good tbf but if no problem before, I see where you’re coming from


Sent from my iPhone using Tapatalk

 

[prt57]

I can’t quite make out from the photo if the input to the hpfp is a hard line or a flexible “rubber” tube. If the endgame code is AXX it imeill have the hard line and if BWA it will have the flexible tube.
so if it has the flexible tube it has been known that pieces of the rubber can break off and cause either a full or a partial blockage to the HPFP.
Again assuming you have the flexible pipe, there is a modification you can research into where the brass inlet to the hpfp is drilled out to 5mm from the existing 1mm. This can assist the lpfp as the restriction into the hpfp is removed.
If you have the hard pipe then I think it is the left hand end of the hard pipe that is drilled. Not so easy as you need to ensure all swarf is removed.
As you are in Manchester, Awesome should be able to assist if you get really stuck.

 

[Davill9]

I can’t quite make out from the photo if the input to the hpfp is a hard line or a flexible “rubber” tube. If the endgame code is AXX it imeill have the hard line and if BWA it will have the flexible tube.
so if it has the flexible tube it has been known that pieces of the rubber can break off and cause either a full or a partial blockage to the HPFP.
Again assuming you have the flexible pipe, there is a modification you can research into where the brass inlet to the hpfp is drilled out to 5mm from the existing 1mm. This can assist the lpfp as the restriction into the hpfp is removed.
If you have the hard pipe then I think it is the left hand end of the hard pipe that is drilled. Not so easy as you need to ensure all swarf is removed.
As you are in Manchester, Awesome should be able to assist if you get really stuck.

Something I didn’t know.
I am intrigued myself now unless you mean like when modifying to the high flow version of hpfp internals upgrade ?

That’s a good shout on awesome too… I forget they are in Manchester as to me it’s always mail order parts down south

 

[prt57]

Some of the high flow hpfps like Loba/APR have that fitting drilled out as part of the upgrade process. So when folks fit Autotech or Vis internals they ought to do it as well.
A post by RTech some years ago recommended doing it to a standard hpfp. 5mm is the recommendation.

 

[prt57]

 

[A4dtmwanted]

Nice… unicorn is brilliant and if they recommend someone- I’d definitely use them 100%

I thought your guy did the checks on vagcom for you for pressure drop etc… that’s the one I was talking about posting on here mate
It is good tbf but if no problem before, I see where you’re coming from


Sent from my iPhone using Tapatalk

He had a delaers system diagnostics which shows fuel values live etc , he said its same a vcds. I'm not sure tbh . , he did say it was holding pressure but not sure if he did it all correctly.
I have booked in with they guy unicorn recommended. So hopefully will get it sorted.
I may also invest in vcds so I can do it myself .

 

[A4dtmwanted]

Nice… unicorn is brilliant and if they recommend someone- I’d definitely use them 100%

I thought your guy did the checks on vagcom for you for pressure drop etc… that’s the one I was talking about posting on here mate
It is good tbf but if no problem before, I see where you’re coming from


Sent from my iPhone using Tapatalk

He had a delaers system diagnostics which shows fuel values live etc , he said its same a vcds. I'm not sure tbh . , he did say it was holding pressure but not sure if he did it all correctly.
I have booked in with they guy unicorn recommended. So hopefully will get it sorted.

 

[A4dtmwanted]

I can’t quite make out from the photo if the input to the hpfp is a hard line or a flexible “rubber” tube. If the endgame code is AXX it imeill have the hard line and if BWA it will have the flexible tube.
so if it has the flexible tube it has been known that pieces of the rubber can break off and cause either a full or a partial blockage to the HPFP.
Again assuming you have the flexible pipe, there is a modification you can research into where the brass inlet to the hpfp is drilled out to 5mm from the existing 1mm. This can assist the lpfp as the restriction into the hpfp is removed.
If you have the hard pipe then I think it is the left hand end of the hard pipe that is drilled. Not so easy as you need to ensure all swarf is removed.
As you are in Manchester, Awesome should be able to assist if you get really stuck.

Hi thanks for that much appreciated. I will have a look today. I try to stay away from awesome not had good experiences with them.to order parts was great but had issues with remaps etc so try to avoid them when I can!!