The ross-tech article.

Have you logged the car? The rosstech article is pressure drop between turbo and throttle body... so if you log it, you will see what the desired and actual boost is.... maybe the map sensor is at fault, when I had that error the DV was jammed open?

I assume all the other errors disappeared like the misfire?

Have you checked for splits on the left side (looking at the engine) on the inlet manifold leading up to the brake servo.

I take it there's no hardware hacks like resistors to try and fool the car into higher boost.

 

I would only guess at a small leak in the pipe work from the turbo through the intercoolers.
Can you rig up a pressure test through the pipe work to the throttle?
It sounds like you've had a few problems, so hopefully this is just the last one.
Do you still get the misfire error as well? Even though you've replaced the coil?

 

I would only guess at a small leak in the pipe work from the turbo through the intercoolers.
Can you rig up a pressure test through the pipe work to the throttle?
It sounds like you've had a few problems, so hopefully this is just the last one.
Do you still get the misfire error as well? Even though you've replaced the coil?

Yes I still get the misfire errors. I've not done a pressure test... honestly not sure how to do that. Could you link me to whatever product you use? I can probably figure out how to do a pressure test from there

 

You are definitely clearing the errors?

 

You are definitely clearing the errors?

Yes I'm clearing the errors with VCDS every time

 

The ross-tech article.

Have you logged the car? The rosstech article is pressure drop between turbo and throttle body... so if you log it, you will see what the desired and actual boost is.... maybe the map sensor is at fault, when I had that error the DV was jammed open?

I assume all the other errors disappeared like the misfire?

Have you checked for splits on the left side (looking at the engine) on the inlet manifold leading up to the brake servo.

I take it there's no hardware hacks like resistors to try and fool the car into higher boost.

Sorry I'm a bit of a noob... this article http://wiki.ross-tech.com/wiki/index.ph ... 297/004759 ?
I'm not sure what you mean by 'logged the car.' Basically I can go in and find whatever code ross tech uses and it will show me boost and also what boost it should have
Haven't replaced the MAP sensor, I could try that.

No, none of the errors disappeared. I always get all 4 errors.

I've looked before for all types of splits/cracks... I'll go look again. And no, no hardware hacks

 

Okay so I looked for any cracks on the line from the intake manifold to brake servo, saw nothing

Tried to do a log: using this website https://www.ross-tech.com/vag-com/m_blocks/110-119.html
and group #115 (I think that's the correct one to use). Only saw actual pressure value sometimes exceed specified value by 10-20mbar

One thing of note, I logged group #030 for oxygen sensors and it appears sensor #2 is never active... maybe this is my issue?

 

I don't really know the vcds blocks.

But the o2 sensors are bank 1 sensor 1 and bank 1 sensor 2 you don't have a bank 2 as that is v6s

 

I don't really know the vcds blocks.

But the o2 sensors are bank 1 sensor 1 and bank 1 sensor 2 you don't have a bank 2 as that is v6s

Yeah sorry I meant bank 1 sensor 2... It's never giving the readout "sensor ready"

But I do get "sensor ready" for bank 1 sensor 1

 

I don't think the post cat sensor does anything, mine is coded out for sports / de cat.

Is everything properly plumbed in?

Underneath the inlet manifold there's the two 4mm connectors for FPR and N249 (or straight to DV if N249 deleted) on the left and in the centre there's a bigger (maybe 6mm) connector which connects to the PCV valve.

I think if you run blocks 1, 31 and 32? You can view long term and short term fuel trims. And then if you clear all errors (even if there are none)? That will reset the fuel trims. If there's an air leak it will be easy to tell.

 

Don't discount the "P0420 Catalytic system efficiency below threshold" error being the Cat itself failing.

I got my V6 in 2013 and have been getting "16804 - Catalyst System; Bank 1 P0420 - 001 - Efficiency Below Threshold" errors intermittently, mainly if driven gently/cruising.

At the end of 2019 I purchased a Scorpion system and Lucifer SportsCats, with the intension of fitting them after its Feb 2020 MOT... but with the :roll: situation in 2020 I only got round to fitting them last Friday.
When we got the old Cat off we could see a hole down the centre of the Bank 1 Cat........!

Explains why it only just got through the last few MOT emissions tests too... :lol:

 

Don't discount the "P0420 Catalytic system efficiency below threshold" error being the Cat itself failing.

I got my V6 in 2013 and have been getting "16804 - Catalyst System; Bank 1 P0420 - 001 - Efficiency Below Threshold" errors intermittently, mainly if driven gently/cruising.

At the end of 2019 I purchased a Scorpion system and Lucifer SportsCats, with the intension of fitting them after its Feb 2020 MOT... but with the :roll: situation in 2020 I only got round to fitting them last Friday.
When we got the old Cat off we could see a hole down the centre of the Bank 1 Cat........!

View attachment 467247

Explains why it only just got through the last few MOT emissions tests too... :lol:

Sooooo not sure if this is good or bad but I dropped my current cats to look inside and they look good from what I can tell

 

I don't think the post cat sensor does anything, mine is coded out for sports / de cat.

Is everything properly plumbed in?

Underneath the inlet manifold there's the two 4mm connectors for FPR and N249 (or straight to DV if N249 deleted) on the left and in the centre there's a bigger (maybe 6mm) connector which connects to the PCV valve.

I think if you run blocks 1, 31 and 32? You can view long term and short term fuel trims. And then if you clear all errors (even if there are none)? That will reset the fuel trims. If there's an air leak it will be easy to tell.

Hmmm so no sense in buying a new O2 sensor?

Yeah I just deleted the N249 (thought maybe there was a leak in there) and plumbed in my own lines from manifold to DV and manifold to FPR. Had the codes both before and after doing that. I've seen the PCV connector but can try to look at it more thoroughly. I'll try to look at blocks 1, 31, and 32 tonight after work

 

Don't discount the "P0420 Catalytic system efficiency below threshold" error being the Cat itself failing.

I got my V6 in 2013 and have been getting "16804 - Catalyst System; Bank 1 P0420 - 001 - Efficiency Below Threshold" errors intermittently, mainly if driven gently/cruising.

At the end of 2019 I purchased a Scorpion system and Lucifer SportsCats, with the intension of fitting them after its Feb 2020 MOT... but with the :roll: situation in 2020 I only got round to fitting them last Friday.
When we got the old Cat off we could see a hole down the centre of the Bank 1 Cat........!



Explains why it only just got through the last few MOT emissions tests too... :lol:

Ouch. I hope that's not my issue, sounds expensive. I also don't get why that would cause misfires too, though

 

Don't discount the "P0420 Catalytic system efficiency below threshold" error being the Cat itself failing.

I got my V6 in 2013 and have been getting "16804 - Catalyst System; Bank 1 P0420 - 001 - Efficiency Below Threshold" errors intermittently, mainly if driven gently/cruising.

At the end of 2019 I purchased a Scorpion system and Lucifer SportsCats, with the intension of fitting them after its Feb 2020 MOT... but with the :roll: situation in 2020 I only got round to fitting them last Friday.
When we got the old Cat off we could see a hole down the centre of the Bank 1 Cat........!



Explains why it only just got through the last few MOT emissions tests too... :lol:

Ouch. I hope that's not my issue, sounds expensive. I also don't get why that would cause misfires too, though

You could have (probably have) several unrelated issues.

 

I would only guess at a small leak in the pipe work from the turbo through the intercoolers.
Can you rig up a pressure test through the pipe work to the throttle?
It sounds like you've had a few problems, so hopefully this is just the last one.
Do you still get the misfire error as well? Even though you've replaced the coil?

Yes I still get the misfire errors. I've not done a pressure test... honestly not sure how to do that. Could you link me to whatever product you use? I can probably figure out how to do a pressure test from there

Sorry, didn't check in yesterday. There is no kit for this, you will have to Jerry-rig/Heath Robinson something together to test the circuit.

Before I start, you might not want to progress with this because it is a real arse!

First stage is to pressure test. You will need to disconnect the pipe from the turbo and the inlet. Then you will need two solid circular items and a jubilee clips to block off the ends you have disconnected. I have used bearing press kit for this before, which worked well. Then use one of the off take pipes for the valves, and plumb in the valve from a compressor ideally. If you haven't got one of those, you can use a foot pump. Clamp the pump valve into the off-take using another piece of rubber tubing.

Pump a load of air in and leave it for a bit. If the pressure doesn't drop, there isn't a leak.
If it does drop, then you are into the realms of taking the air circuit out and test each component in water and compressed air in a similar way.

Sorry, it isn't a straightforward solution.

 

I still don't understand about the errors not disappearing?

Have you cleared them with the engine off and made sure they are not there. And they only come back after a few minutes running?

Did you check the fuel trim blocks 31 and 32 I thing sort term and long term..

The coil wiring can go brittle and / or dodgy earth connectors on cam cover..

 

I don't think the post cat sensor does anything, mine is coded out for sports / de cat.

Is everything properly plumbed in?

Underneath the inlet manifold there's the two 4mm connectors for FPR and N249 (or straight to DV if N249 deleted) on the left and in the centre there's a bigger (maybe 6mm) connector which connects to the PCV valve.

I think if you run blocks 1, 31 and 32? You can view long term and short term fuel trims. And then if you clear all errors (even if there are none)? That will reset the fuel trims. If there's an air leak it will be easy to tell.

Running blocks 1, 31, and 32 it seems my lambda stays pretty close to 1. Not sure how to view long or short term fuel trim

Group 32 I don't really understand... it says my bank 1 sensor 1 idle is about 2.6% and my bank 1 sensor 1 partial load is -7%... no idea what to make of these #s

Attached the log for those blocks

 

I still don't understand about the errors not disappearing?

Have you cleared them with the engine off and made sure they are not there. And they only come back after a few minutes running?

Did you check the fuel trim blocks 31 and 32 I thing sort term and long term..

The coil wiring can go brittle and / or dodgy earth connectors on cam cover..

I clear them and then they come back but not for some time... sometimes after 40kms of driving, sometimes up to 250kms later

 

I had a cheap coil pack and it vibrated up the tube leading to an occasional misfire.. I also bought some bkr7s from ebay and one of them cylinder 1 failed, it would only miss like a lul if hot and ~5500rpm..

If its intermittent is it possibly wiring? Or maybe oil getting into the spark plug hole? From the centre cam gasket..

 

I had a cheap coil pack and it vibrated up the tube leading to an occasional misfire.. I also bought some bkr7s from ebay and one of them cylinder 1 failed, it would only miss like a lul if hot and ~5500rpm..

If its intermittent is it possibly wiring? Or maybe oil getting into the spark plug hole? From the centre cam gasket..

Could be wiring. Tracing that back is going to be a bitch.

I saw there was a bunch of oil on the spark plug so I replaced the valve cover gasket... haven't checked since I did that but I assumed that fixed it

Just replaced the downstream O2 sensor :/. If the code comes back I'll order some new PCV pipes and an intake manifold gasket and try replacing that. Unfortunately shipping takes a long time

 

Still getting the codes... going to take it apart a bit and order new PCV hoses today. Pretty hard to find online... if you have any recommendations on places to shop for them I'll take any advice.

Will probably replace the intake manifold gasket while I'm at it

 

I don't think the post cat sensor does anything, mine is coded out for sports / de cat.

Is everything properly plumbed in?

Underneath the inlet manifold there's the two 4mm connectors for FPR and N249 (or straight to DV if N249 deleted) on the left and in the centre there's a bigger (maybe 6mm) connector which connects to the PCV valve.

I think if you run blocks 1, 31 and 32? You can view long term and short term fuel trims. And then if you clear all errors (even if there are none)? That will reset the fuel trims. If there's an air leak it will be easy to tell.

Running blocks 1, 31, and 32 it seems my lambda stays pretty close to 1. Not sure how to view long or short term fuel trim

Group 32 I don't really understand... it says my bank 1 sensor 1 idle is about 2.6% and my bank 1 sensor 1 partial load is -7%... no idea what to make of these #s

Attached the log for those blocks

Sorry it is 32 and 33 not 31 and 32

Essentially, if you are leaking air you will get fuel trims out side the target range...

There are some other linked videos, essentially the goal is 0%, long term fuel trims are adaptions based on how much more or less fuel is required to correct for unmetered air (a leak) as idle is always at vacuum. But there are acceptable settings. Like maybe 4% for long term and -10 to +10 for short term. If you have -2.6 in LT and clear all errors (even if none) fuel trims are reset and then looking at ST FT your short term might be -10,+7,'-10,+7.... etc then after a while the LTFT might be -1 then your STFT should be -9,+8,-9,+8... etc. Short Term always go less, more,less,more but its ideal to get the gap between the numbers smaller..

There's also a Map table called FKVVS which stores a profile based on Audi Stock Injectors, but that sometimes needs adjusting... there's a tool you can get to tell you the best new values, it's based on the throttle position (maybe load?) and revs, and you drive around trying to cover as many rpm, TP combinations and it will show you the adjustments for your table..

 

I don't think the post cat sensor does anything, mine is coded out for sports / de cat.

Is everything properly plumbed in?

Underneath the inlet manifold there's the two 4mm connectors for FPR and N249 (or straight to DV if N249 deleted) on the left and in the centre there's a bigger (maybe 6mm) connector which connects to the PCV valve.

I think if you run blocks 1, 31 and 32? You can view long term and short term fuel trims. And then if you clear all errors (even if there are none)? That will reset the fuel trims. If there's an air leak it will be easy to tell.

Running blocks 1, 31, and 32 it seems my lambda stays pretty close to 1. Not sure how to view long or short term fuel trim

Group 32 I don't really understand... it says my bank 1 sensor 1 idle is about 2.6% and my bank 1 sensor 1 partial load is -7%... no idea what to make of these #s

Attached the log for those blocks

Sorry it is 32 and 33 not 31 and 32

Essentially, if you are leaking air you will get fuel trims out side the target range...

There are some other linked videos, essentially the goal is 0%, long term fuel trims are adaptions based on how much more or less fuel is required to correct for unmetered air (a leak) as idle is always at vacuum. But there are acceptable settings. Like maybe 4% for long term and -10 to +10 for short term. If you have -2.6 in LT and clear all errors (even if none) fuel trims are reset and then looking at ST FT your short term might be -10,+7,'-10,+7.... etc then after a while the LTFT might be -1 then your STFT should be -9,+8,-9,+8... etc. Short Term always go less, more,less,more but its ideal to get the gap between the numbers smaller..

There's also a Map table called FKVVS which stores a profile based on Audi Stock Injectors, but that sometimes needs adjusting... there's a tool you can get to tell you the best new values, it's based on the throttle position (maybe load?) and revs, and you drive around trying to cover as many rpm, TP combinations and it will show you the adjustments for your table..

Thank you! This helped a lot.

So I'll update as this progresses but my LT FT seems to be around +2%... not enough to throw a code. ST FT hovers around +/- 2%. So nothing crazy there

HOWEVER the good news is that I was spraying starter fluid around the engine bay and measuring ST FT while doing so. I found spraying it right on the PCV caused a spike to around -20% ST FT. So I ordered some parts to replace the PCV hoses. Supposed to ship here by Friday, surprising how fast that is

Also, the code for the pressure drop between turbo & throttle body registers almost immediately after a reset. The other 3 can take a while to materialize

Thanks again for the help Stuart, I'll update you as I go. Hopefully will replace all PCV stuff this weekend and the intake manifold gasket while I'm at it. Was thinking perhaps since the LT FT seems normal that maybe my fuel injectors are just not dumping enough fuel? Or the cat is bad? I'll wait until after replacing the PCV to assess

 

Do you have access to an air compressor?

I have a 3D printed boost test adapter you are welcome to borrow to do a proper pressure test.

It'll probably work with a decent bike pump or foot pump too.

Drop me a DM.

 

Do you have access to an air compressor?

I have a 3D printed boost test adapter you are welcome to borrow to do a proper pressure test.

It'll probably work with a decent bike pump or foot pump too.

Drop me a DM.

Hey tried to direct message but it won't let me because I'm too new to the forum.

Anyway, I do have an air compressor and also a 3D printer. If you link me to an STL I can print it and hopefully figure it out from there