Audi S3 boosting problems.

[ceS3r]

Hi everyone. I've been fixing up minor problems with my s3.. Coilpacks were constantly going, so I replaced with hitachi screwed ones. Only bought 3 of them because they only had 3 in stock, I'm waiting for the next one to get it next week.. currently 3 hitachi and 1 push down. Did the n249 bypass also, but when I started the car, there was a huge sucking noise, dv fluttering without reving and horrible idle, it turned down to be the vac lines under the inlet mani that were all broken. Replaced them with fuel pressure hoses, all of them. Now, the car is spiking to 21psi and then goes down to 15-16, but some times, in 2nd gear in full throttle from like 2000rpm, when the car hits full boost, it seems to hesistate, no misfire, but it's like lack of power. Sometimes it just goes straight into limp mode.

I connected my vag com and it says about the egt sensor implausible signal (Been like that for awhile), evap sys incorrect flow (No idea what this is) and charge preassure upper limit exceeded.

What should I check? Could be a faulty n75? Or maybe the stock dv isn't holding that much psi?

Car is a 2003 S3 BAM 225 with cone filter and decat, n249 bypass, not chipped.

Any help would be appreciated.

 

[<tuffty/>]

EGT sensor needs addressing as this will just overfuel all the time and the bore wash will accelerate the wear on the bores and rings (been there)

The evap code sounds like its related to a vacuum leak from a split pipe...

The over boost is normally a split pipe too... especially on a std map...

Basically... check/replace EGT sensor... check all the pipes for splits... evap goes to the top of the throttle body and to the TIP... the pipes pick up from the black hard pipe running along the top of the scuttle at the back of the engine bay... evap for the TIP goes to the bottom of the TIP from memory

Post the actual codes next time though as this makes it easy to diagnose...

<tuffty/>

 

[ceS3r]

EGT sensor needs addressing as this will just overfuel all the time and the bore wash will accelerate the wear on the bores and rings (been there)

The evap code sounds like its related to a vacuum leak from a split pipe...

The over boost is normally a split pipe too... especially on a std map...

Basically... check/replace EGT sensor... check all the pipes for splits... evap goes to the top of the throttle body and to the TIP... the pipes pick up from the black hard pipe running along the top of the scuttle at the back of the engine bay... evap for the TIP goes to the bottom of the TIP from memory

Post the actual codes next time though as this makes it easy to diagnose...

<tuffty/>

Codes are:

16825
17963
And I don't remember the EGT code.. sorry.. Will scan tomorrow and post it

I took it last week to a local garage/friends of mine, and they removed the inlet mani and replaced all that vac hoses too with fuel pressure hoses as I said, I still have to look for split hoses like the ones that goes to the n75. Boost gauge is reading 20-18 mmHg, which I think is a normal vac pressure right? Not sure though.. What other pipes can I check for split?

 

[<tuffty/>]

Humm... don't know then... assuming they have done the job right (no offence to your friends at the garage) but its easy to get wrong if not familiar with the setup... get a check valve in the wrong place or remove something thinking its not needed then anything can go wrong...

On an AMK/BAM its a fairly straightforward task to do a PCV delete that removes all the pipes under the inlet manifold to prevent future problems...

Without knowing exactly what they have done then I can't honestly suggest where to start... the OE stuff under the inlet looks like this...

Maybe some pics might help...

<tuffty/>

 

[ceS3r]

Humm... don't know then... assuming they have done the job right (no offence to your friends at the garage) but its easy to get wrong if not familiar with the setup... get a check valve in the wrong place or remove something thinking its not needed then anything can go wrong...

On an AMK/BAM its a fairly straightforward task to do a PCV delete that removes all the pipes under the inlet manifold to prevent future problems...

Without knowing exactly what they have done then I can't honestly suggest where to start... the OE stuff under the inlet looks like this...

Maybe some pics might help...

<tuffty/>

Here are some pics tuffty


From above before mani installation (Looks like the pic you showed to me.)


From above after the installation






This is the evap's pipe you're talking about right?

 

[ceS3r]

There was also oil in the metal pipe that comes from the turbo housing, and also in the pipe that comes from the intercooler to the inlet mani, so clearly my turbo is burning oil.. Could this also be a cause for it to hold back on full boost?

 

[<tuffty/>]

I have to say I am a little concerned with whats been done... the servo vacuum doesn't look right at all and I can't really make out most of the connections there... you would have been better to bin it all off tbh... the servo vac hose that typically fits to the 90 degree outlet on the side on the inlet mani is all you need to use, the 2 little outlets over the alternator, one goes to the FPR (and ONLY the FPR... you have tapped your boost gauge from this... put simply, don't!) and the other goes to the DV (tee off for a boost gauge if you need too) and the larger centre outlet just needs blocking off... then you remove the rubber Tee that joins the PCV elbow that comes out of the block to the plastic pipe that goes up to the cam cover funky looking 3 outlet rubber jobber and just use a bit of rubber or silicon hose to join them... that its for a PCV/bin off all the crap under manifold style delete...

I can't tell for sure if this is causing your issues directly but from the pics it doesn't look right...

Yes, the last pic is one of the EVAP hoses... follow that one back to the bulkhead and on the right of the hard pipe its attaches too there will be another pipe that goes to the bottom of the TIP... both should have check valves from memory...

<tuffty/>

 

[ceS3r]

I have to say I am a little concerned with whats been done... the servo vacuum doesn't look right at all and I can't really make out most of the connections there... you would have been better to bin it all off tbh... the servo vac hose that typically fits to the 90 degree outlet on the side on the inlet mani is all you need to use, the 2 little outlets over the alternator, one goes to the FPR (and ONLY the FPR... you have tapped your boost gauge from this... put simply, don't!) and the other goes to the DV (tee off for a boost gauge if you need too) and the larger centre outlet just needs blocking off... then you remove the rubber Tee that joins the PCV elbow that comes out of the block to the plastic pipe that goes up to the cam cover funky looking 3 outlet rubber jobber and just use a bit of rubber or silicon hose to join them... that its for a PCV/bin off all the crap under manifold style delete...

I can't tell for sure if this is causing your issues directly but from the pics it doesn't look right...

Yes, the last pic is one of the EVAP hoses... follow that one back to the bulkhead and on the right of the hard pipe its attaches too there will be another pipe that goes to the bottom of the TIP... both should have check valves from memory...

<tuffty/>

So.. you're saying that from what you see, it's not done well? It is bad to put the boost gauge Tee on the fpr line? I should locate the Tee of the boost gauge in the DV line? The only thing I need connected to the inlet mani would be the brake servo vacuum, that is the one that is connected in the left part of the mani looking it from above right? Am I right from what I understood?

Basically, I should delete the pcv system.. A friend of mine just ordered a bunch of tools, I'll wait for them and start working on it myself (Don't have much money left to spend on garage)..

Another question, should I fit a catch can by deleting this system? Thank you Tuffty for your help.

 

[<tuffty/>]

So.. you're saying that from what you see, it's not done well? It is bad to put the boost gauge Tee on the fpr line? I should locate the Tee of the boost gauge in the DV line? The only thing I need connected to the inlet mani would be the brake servo vacuum, that is the one that is connected in the left part of the mani looking it from above right? Am I right from what I understood?

Basically, I should delete the pcv system.. A friend of mine just ordered a bunch of tools, I'll wait for them and start working on it myself (Don't have much money left to spend on garage)..

Another question, should I fit a catch can by deleting this system? Thank you Tuffty for your help.

I am saying it doesn't look right to me... the hose is quite large and looks reinforced (high pressure stuff maybe) which can cause issues if its not sealing properly etc...

The FPR is reeeealy important and should have its own vacuum source.. if the line fails (due a hose popping off or a fault with a boost gauge) then you will lose fuel pressure under boost and the engine is in danger of running lean.. this is bad and can lead to catastrophic engine failure...

Have a read of this thread (from the FAQ's in the stickies)
http://www.audi-sport.net/vb/a3-s3-...de-how-fit-catch-can-simplify-pcv-system.html

You don't need to fit a catch can to do a PCV delete under the inlet mani but if you want to remove all oil fumes etc from getting into the inlet charge (this can in worst case dilutes the octane of the fuel and promote knocking which the ECU will detect and pull ignition advance to sort loosing you power) then fit a catch can and remove the PCV pipe going to the TIP too

<tuffty/>

 

[ceS3r]

I am saying it doesn't look right to me... the hose is quite large and looks reinforced (high pressure stuff maybe) which can cause issues if its not sealing properly etc...

The FPR is reeeealy important and should have its own vacuum source.. if the line fails (due a hose popping off or a fault with a boost gauge) then you will lose fuel pressure under boost and the engine is in danger of running lean.. this is bad and can lead to catastrophic engine failure...

Have a read of this thread (from the FAQ's in the stickies)
http://www.audi-sport.net/vb/a3-s3-...de-how-fit-catch-can-simplify-pcv-system.html

You don't need to fit a catch can to do a PCV delete under the inlet mani but if you want to remove all oil fumes etc from getting into the inlet charge (this can in worst case dilutes the octane of the fuel and promote knocking which the ECU will detect and pull ignition advance to sort loosing you power) then fit a catch can and remove the PCV pipe going to the TIP too

<tuffty/>

I amactually reading that thread right now lol..

Cheers tuffty thank you very much, I will connect right away the boost gauge to the dv valve and connect directly the fpr to the inlet mani while I wait for all the tools to start doing the PCV delete..

One last question, if oil enters in the inlet mani, then it will dilute with the gas and lower the octane right? so, as my turbo is letting oil pass, this could be the problem with the lack of power.. I'm looking forward to fix the turbo also.

 

[<tuffty/>]

Take the hose off the the throttle body, if there is oil there then oil is being blown around the charge system (normally from turbo seals but can be from worn rings/PCV system...)

If you are going into limp from the overboost issue this will be your power problem... you need to make sure the pipe work etc is all as it should be first to eliminate this as a cause... I would also consider doing some logging if you can with VCDS... this can gives clues as to whats going on...

There is another link in the stickies with some basic info on stuff (its the same one thats in my signature... not my build thread but feel free to read that too lol)

If oil is getting into the inlet manifold then yes this will dilute the fuel and lower the octane... as your car is not mapped then the performance drop is generally not massive as OE timing is very conservative... I suspect your lack of power is from limp mode... limp mode is 0.5bar/7psi... std boost 0.8bar/12psi (give or take a tad)

I notice from the Tee you have for your boost gauge that you have a Stack gauge? I would check the tightness of the top brass nut on the brass fitting as almost all installations I have seen of these you can 'turn' the pipe in it... this needs to be tighter as its a vacuum/boost leak... the olive thats in there just needs to be a little tight... don't over do it else you will crush the pipe... just enough that the pipe doesn't turn...

<tuffty/>

 

[ceS3r]

Take the hose off the the throttle body, if there is oil there then oil is being blown around the charge system (normally from turbo seals but can be from worn rings/PCV system...)

If you are going into limp from the overboost issue this will be your power problem... you need to make sure the pipe work etc is all as it should be first to eliminate this as a cause... I would also consider doing some logging if you can with VCDS... this can gives clues as to whats going on...

There is another link in the stickies with some basic info on stuff (its the same one thats in my signature... not my build thread but feel free to read that too lol)

If oil is getting into the inlet manifold then yes this will dilute the fuel and lower the octane... as your car is not mapped then the performance drop is generally not massive as OE timing is very conservative... I suspect your lack of power is from limp mode... limp mode is 0.5bar/7psi... std boost 0.8bar/12psi (give or take a tad)

I notice from the Tee you have for your boost gauge that you have a Stack gauge? I would check the tightness of the top brass nut on the brass fitting as almost all installations I have seen of these you can 'turn' the pipe in it... this needs to be tighter as its a vacuum/boost leak... the olive thats in there just needs to be a little tight... don't over do it else you will crush the pipe... just enough that the pipe doesn't turn...

<tuffty/>

I think you understood me wrong.. I get lack of power when the boost spools up, up to 16-17 psi.. similar as misfire on full boost but no, is not misfire, also I'm not getting any misfire code on vag com. But, sometimes, it just goes straight into limp mode, but they are two different cases I'm describing here. PD: English is not my native language so forgive me if I'm not making myself clear enough.

What do you mean with "Stack gauge"? Sorry for my ignorance..

 

[<tuffty/>]

I think you understood me wrong.. I get lack of power when the boost spools up, up to 16-17 psi.. similar as misfire on full boost but no, is not misfire, also I'm not getting any misfire code on vag com. But, sometimes, it just goes straight into limp mode, but they are two different cases I'm describing here. PD: English is not my native language so forgive me if I'm not making myself clear enough.

What do you mean with "Stack gauge"? Sorry for my ignorance..

Ah... makes sense now... 16-17psi is not standard boost... the reason you are losing power is because its boosting to 16/17psi and the ECU is hitting limp with over boost protection... 16/17psi is an issue... try unplugging the N75 valve electrically... this should only allow the turbo to run on actuator pressure... if its still trying to make more boost than 7psi then the problem is with the N75 valve or the pipework around it...

What I meant by Stack gauge is your boost gauge looks like its made by Stack (a brand of gauge)

<tuffty/>

 

[ceS3r]

Ah... makes sense now... 16-17psi is not standard boost... the reason you are losing power is because its boosting to 16/17psi and the ECU is hitting limp with over boost protection... 16/17psi is an issue... try unplugging the N75 valve electrically... this should only allow the turbo to run on actuator pressure... if its still trying to make more boost than 7psi then the problem is with the N75 valve or the pipework around it...

What I meant by Stack gauge is your boost gauge looks like its made by Stack (a brand of gauge)

<tuffty/>

Makes sense now to me too lol.. ok will unplug n75 and give it a run and post results

Boost gauge is an Autometer

 

[<tuffty/>]

Makes sense now to me too lol.. ok will unplug n75 and give it a run and post results

Boost gauge is an Autometer

Ah... ok.. maybe they are using a similar Tee piece to the Stack gauges... worth a check anyway

<tuffty/>

 

[ceS3r]

Hi Tuffty, I disconnected the n75 today, and it only made 5 psi, no more no less.. I had a personal mechanic once who moved the actuator to "increase psi" the car started giving me limp mode, so I moved back.. is there a way to know the stock position of the actuator nut?

 

[<tuffty/>]

Stock preload should be three turns from hand tight on the wastegate... so, tighten the outside nut (the one on the end of the threaded rod of the actuator) by hand (no spanners) until then is no movement in the wastegate (this means its fully closed) then tighten the nut with a spanner three whole turns... tighten the locking nut (the one on the side facing the actuator) to lock it all in place and replace the clip...

There is no point in trying to increase your boost this way or any other way for that matter as the ECU will just go into limp mode... the ONLY way you will get more boost and not have problems is a remap... as soon as the ECU detects a boost variation from what it thinks it should be doing then it will hit limp...

<tuffty/>

 

[s3dave]

Stock preload should be three turns from hand tight on the wastegate... so, tighten the outside nut (the one on the end of the threaded rod of the actuator) by hand (no spanners) until then is no movement in the wastegate (this means its fully closed) then tighten the nut with a spanner three whole turns... tighten the locking nut (the one on the side facing the actuator) to lock it all in place and replace the clip...

Thats assuming you have an origonal actuator and not a replacement/uprated one...

You say you are only getting 5psi on actuator pressure? that is too low on an s3, The best way to set it is with a bike pump (with a gauge)on the actuator and see what the crack pressure is then adjust the rod to suit..

 

[ceS3r]

Thats assuming you have an origonal actuator and not a replacement/uprated one...

You say you are only getting 5psi on actuator pressure? that is too low on an s3, The best way to set it is with a bike pump (with a gauge)on the actuator and see what the crack pressure is then adjust the rod to suit..

It's standard actuator.. will try that too.. thanks for your replies. Std actuator pressure should be 7 psi?

 

[ceS3r]

Little update here. So, I now have all 4 hitachi bolt in coil packs, all pcv under the mani replaced with fuel pressure hoses (stronger I think). The car just ran good the first time after doing all of this jobs, it got my wheels spinning, but that was only the first time, since then, it only has running problems.. I get sometimes a huuuge overboost up to 23+ psi.. Sometimes when I just do part throttle it holds 15-16 psi and runs good, but when I step on the gas it goes up to 20 or more and judder, or sometimes, misfire.. Although vagcom doesn't show up any codes about misfires, just the same as always, that would be 17861 - Exhaust Gas Temp Sensor (short or something), 16825 Evap Sys Incorrect Flow, and 17963 Maximun charge pressure limit exceeded. I've checked all the hoses and are fine, tried to run with unplugged MAF and same issues.. I'm thinking next to change the spark plugs and do the actuator thing (Haven't done yet).. Any thought would be appreciated..

PS: Excuse my bad english..

 

[ceS3r]

Also, looking forward to replace EGT sensor, the bad thing is....... It's to expensive..

 

[ceS3r]

Hi! I'm just picking this old thread to update you guys that I fixed my boost problems. It was the wastegate preload, in some other garage a guy moved the wastegate way to tight I think, so I just moved back to stock position, now it boosts fine! Thank you all cheers