Audi S3 8l Pressure drop between turbo and TB !?!

[Dennis Ismailov]

Hi guys. I have S3 8l 2001 AMK .. There is a problem which I cant handle with .. The car is still stock , and I have a boost loss , what I mean is that ..

When I start to accelerate hard it has no problems , the boost gauge shows like 0.7 bar's of boost , but when I took my foot of the throttle the problem kicks in and its like no boost , I mean the gauge shows 0.3 bar's of boost maximum ..

When I turn the car OFF , then ON , there is no problem till the next time with the hard acc. The DV is Bailey DV26 dualpiston , have no boost leaks between components , seems like I have no vacuum leak too ..

I have tried with another MAF from S3 8l AMK , the MAP seems to be OK , N249 bypassed , although I have tried with another DV Forge .. Do you have any suggestions ??

Thats the code what VCDS give - Pressure drop between turbo and TB ( I have cleaned the TB - needed no adaptation !!! ) When we clean the code on a running car , it seems to be okay , but then the code appears again ... What shall I do ??? Sorry for my bad English , greetings from Bulgaria ))

 

[fisher72]

You need to do smoke test for boost leaks if the ecu senses a leak it cuts the boost mine was doing it the tunner i used altered the map so the ecu couldn't see the boost drop trying running it for a day with the maf disconnected it will throw a error for your traction control but i bet it won't go into soft limp

 

[desertstorm]

Don't use dump valves that vent to atmosphere. They don't work well on a standard car at all.The ECU measures air going into the engine through the MAF. Any air dumped and unmetered will mean the ECU is unable to properly calculate the correct mixture. Refit a standard dump valve and make sure it vents into the intake.

 

[<tuffty/>]

Ahhh... ye olde 17705 fault code

http://wiki.ross-tech.com/wiki/index.php/17705/P1297/004759

This is is a known software bug and the code tends to pop up when ambient temps are 5degs of below (the little snowflake appears in the DIS)

Results in loss of boost and cycling the ignition clears it..

It also of course could be down to a genuine air leak and if using an atmos valve then that could explain it... change the DV to a new OE plastic valve, get a smoke test to check for leaks and fix any that are found...

The fault code normally pops up due to the bug on mapped cars but as yours isn't mapped then its more likely the DV you are using and potentially any other leak you may have

<tuffty/>

 

[fisher72]

I had it mapped out by rtech never done it again

 

[Stuart B]

needed to fix my AMK too, doesn't occur in a standard BAM map...

 

[fisher72]

needed to fix my AMK too, doesn't occur in a standard BAM map...

View attachment 174028

Its mad what you go through to sort the pressure drop problem out only been trying for 3 years

 

[Stuart B]

It requires a map change.

 

[fisher72]

Ive had my map changed

 

[Dennis Ismailov]

You need to do smoke test for boost leaks if the ecu senses a leak it cuts the boost mine was doing it the tunner i used altered the map so the ecu couldn't see the boost drop trying running it for a day with the maf disconnected it will throw a error for your traction control but i bet it won't go into soft limp

Ahhh... ye olde 17705 fault code

http://wiki.ross-tech.com/wiki/index.php/17705/P1297/004759

This is is a known software bug and the code tends to pop up when ambient temps are 5degs of below (the little snowflake appears in the DIS)

Results in loss of boost and cycling the ignition clears it..

It also of course could be down to a genuine air leak and if using an atmos valve then that could explain it... change the DV to a new OE plastic valve, get a smoke test to check for leaks and fix any that are found...

The fault code normally pops up due to the bug on mapped cars but as yours isn't mapped then its more likely the DV you are using and potentially any other leak you may have

<tuffty/>

I bought the car already mapped .. but we didnt like the way it was done and we put the original soft. When it was mapped , it was doing the same problem , over and over again

 

[<tuffty/>]

If there are no air leaks and its an AMK then you will just need to get it mapped out or live with it until the warmer weather comes mate...

<tuffty/>

 

[Dennis Ismailov]

If there are no air leaks and its an AMK then you will just need to get it mapped out or live with it until the warmer weather comes mate...

<tuffty/>

Whats about the warmer weather bro ?! Soon will be mapped , then we will see ?

 

[Dennis Ismailov]

You need to do smoke test for boost leaks if the ecu senses a leak it cuts the boost mine was doing it the tunner i used altered the map so the ecu couldn't see the boost drop trying running it for a day with the maf disconnected it will throw a error for your traction control but i bet it won't go into soft limp

the tunner i used altered the map so the ecu couldn't see the boost drop ?!? Wthat do you mean with that mate , how did he do that with the map ?

 

[<tuffty/>]

The issue manifests itself when on cold start and ambient temps are 5degrees or lower...

I had the same issue back when I first had my S3.. It was mapped with custom code at the time so they fixed the issue in the map..

Have done it myself on subsequent maps while running the factory ecu

It's more annoying than anything and always clears (from my experience at least) when you cycle the ignition (vode remains of course)

<tuffty/>

 

[Dennis Ismailov]

It requires a map change.

you mean map sensor change , or the car to get mapped ?? Because I have cleaned the map sensor , and in vcds the map shows correct according to the boost gauge

 

[<tuffty/>]

you mean map sensor change , or the car to get mapped ?? Because I have cleaned the map sensor , and in vcds the map shows correct according to the boost gauge

Not the map sensor mate... It's a table on the map that needs updating... normally flatten the table FVPDKLDUS to over come this

<tuffty/>

 

[badger5]

needed to fix my AMK too, doesn't occur in a standard BAM map...

View attachment 174028

it does on leon cupra r's

 

[spence79]

Does it do this on a dual carriageway or a motorway where your throttle is like half?


Sent from my iPhone using Tapatalk Pro

 

[Stuart B]

The software bug in my S3 AMK meant that when I started the engine with the DIS showing a snowflake the boost was limited to about 6% (actuator?) until the engine was switched off and on again - so even if I drove 20 miles to work - but you dont get an EML. it would do my head in, I drove to work in the morning thinking the car was broken, then it was fine when I drove home.

I think I needed to drive for about 2 minutes before cycling the ignition but it might have worked immediately, it was something to do with reading a temperature in the intake (perhaps), so I drove for a mile or so to create some heat. You get the feeling someone thought it would be a good safety measure and completed it half-hearted.