Audi S3 No boost, Turbo not kicking in?, help please, A3 S3, Audi

[doughty29]

i have an audi s3 8L Amk 51reg
last week i was driving my car and sudenly had no boost, had it all apart and found that the induction pipe was split, i bought a badger5 tip replacement and no luck.
it is almost as if my car is in limp mode but has only shut off the turbo and not limiting my speed, and without any engine lights on.

i had a look round all the pipes and made sure everything was tight, then unplugged the battery to reset the car, and it seemed to sort my car, but two minutes later it stopped again.

Symtoms: my car feels like a naturally asperated car, can only her the turbo a tiny bit, and almost no pressure escaping from the after market dv. (i have checked to see if it is jammed, and its not)

Things ive done/checked:
I have scanned the car and no errors come up, and no engine lights. the car has been remaped, but im not sure what remap as it was already done before i bought it.
I have unplugged the N75 and made no differance.
I have unplugged the MAP sensor, ran horrible, but no extra power.
I have unplugged the MAF sensor, made a little differance in extra power, but no where near what it was.
I have checked the turbo, the turbine seems fine no play at all, and not seized, no cracks on the turbo that i can see.
when i unplugged the MAF the engine light came on as userall so i dont think it could be the ECU.

Hunches:
The N249 wires have recently been cut as this is got caught up, the N249 is not being used, i am going to get a 330ohm 10watt resistor and connect it up, and see if that sorts it.

also could the larger induction hose be messing with my remap?

could it be my engine mounts?

Does anyone have any ideas? it would be much appreicated.

 

[Dani_B19]

Have you bad the bumper off and checked all the lower boost pipes? So does the car drive but just not pull? Is the speed limited?

 

[doughty29]

i havent had the bumper off but i have had a look under and checked for splits and tightened up the intercooler hoses, the only pipe i couldnt get to was the driver side top part of the intercooler, and no my speed is not limeted, i also can not hear a boost leak.
also the car has tourqe up to 2500 rpm then rises up all the way like a non turbod car.

 

[doughty29]

im begining to think its a boost leak because it holds enough presssure to spool the turbo untill 2500rpm, and then looses its pressure. but i cant see any cracked, split or out of place, any ideas?

 

[Routledge]

Park the car up, and put on the handbrake. Get the clutch to the biting point in 1st gear and slowly apply to the accelerator. At around 3500-4000RPM you'll hear a woosh if there's a boost leak, and get someone else to listen to where it's coming from.

 

[doughty29]

thanks for that, just did it and no 'woosh' but no sound of the dump valve at all.. hmm thanks anyway mate

 

[doughty29]

one more thing, when i put my foot down my traction controll light pops up as if its loosing traction, but i have almost no power and cirtainly dont have enough power to spin a 4wd, could it be my 4wd system stopping my turbo from boosting? thank you all.

 

[daz-20vt]

my s3 has very over sensative tc and will kick in at very annoying times when not needed. think they must just be like that. it doesnt need 4 wheels spinning either if i hit a bumpy road where one will spi s it kicks in. daz

 

[doughty29]

my s3 has very over sensative tc and will kick in at very annoying times when not needed. think they must just be like that. it doesnt need 4 wheels spinning either if i hit a bumpy road where one will spi s it kicks in. daz

are you sure your 4wd system is working?, and do you have decent tyres? mine never used to come up with TC

 

[doughty29]

any ideas welcome, im still stuck

 

[superkarl]

You need the car scanned and logged with vcds.

In no way should the n249 valve be electronically disconnected. Plugged in, yes. Bypassed vaccum pipes, yes. This valve is part of the esp system.

Also check the orientation of the n75 valve is right. You may have fitted it wrong when fitting the b5 tip. In one orientation the car will over boost. In another it will run on actuator only, about 5 psi if the actuator is healthy.

But, the car needs scanning

 

[doughty29]

Put the resistor on the N249 wires and still no luck, I may need to clear any faults on my ecu, but still no luck, anyone got any ideas? And also can you explain the order/ set up of the N75 (which pipe goes where) just to triple check cheers

 

[doughty29]

turned out to be the breather pipe under the inlet manifold, it was poping open under load. also a fuse had blown, all sorted now cheers.

 

[BENJAMIN]

Was this the one I fixed just before Christmas? If so, it's a real nice example.

 

[doughty29]

it was mate cheers, im still changing parts slowly but surly, cheers for that!, im still trying to source an N249 for you.

 

[BENJAMIN]

Glad to hear it. What's next for it?
No stress on the n249, just whenever you find one.

 

[doughty29]

I've replaced the boost pipe that sits ontop of the turbo to a silicone one, I have replaced the crank breather pipe, I need to replace the PCV as mine has failed, bought a new silicone charge pipe, (to replace the red one you saw).
i am putting/ doing the following:
a milltek cat back non res,
a forge slit r DV,
cone filter and cold air feed,
wheel spacers,
replace some worn bushes,
Change discs and pads,
possibly get the clutch done.