Boost Problems, what next? (video)

[S2central.net]

Would need to be LOTS of knock for the ECU to turn off boost... I am of the opinion that the wastegate itself might be at fault - seems to me like it is providing little of no restriction to exhaust gas pressure at high rpm.

The other possibilitry is a 'tired' N75 that doesnt behave properly... have you tried/swapped it with another car ?

Have you checked N75 orientation with another car too ?

[montez]

jus checked unplugged n75 it is just under 0.5 bar now with the spacers in

[montez]

What I have done so far;

• Checked ECU for fault codes
• Checked throttle cable + tps
• Checked and replaced Dv with forge
• Pressure tested intake, both sides of throttle body
• Checked ECU pipes and connector
• Replaced all vacume pipes
• Unpluged MFTS and made no difference
• pressure tested intercooler and mark h connection
• pressure tested the intake manifold and pipes at back
• replaced n75 with s2_bo heavy duty
• checked n75 pipes for leaks
• altitude sensor checked
• checked the wastegate + diaphragm
• checked the turbo for excessive play
• cleaned maf with ipa and tested resistance

[S2central.net]

On a warm idle - report what values you see in Group 0 with vagcom in measuring blocks

[prj]

So which fault codes are you getting?
If it is cutting down to spring boost, and the ECU is doing it, it'll always log a code.

[rs200]

only one solution stay.
your car don't have enough flow from exhaust, so it cant spool good.

friend has same problem on S3..

[montez]

There are no codes on the ecu I have just checked, my version of vagcom is playing up fine, it will not let me see the groups in measuring blocks just the single readings. if you know which of the single readings so use I can get them off.

The only logical place would be the wastegate, unless the ceramic seat at the bottom is damaged? because the waste gate goes from its most open position at high rpm to closed on gear change.

As for n75 I do not have a spare at the moment but it was recently replaced and don't know of anyone else with an s car.

Problem was I changed a lot of things at the same time need to eliminate them all now.

The exhaust is a good shout, I will explore this route to see if there are any obstructions

[prj]

Melted cat, Intercooler full of oil, Throttle not opening fully, leaky bypass valve.

[montez]

Car is Decat , Intercooler Clean, Throttle and TPS checked, Bypass valve checked and replaced

[montez]

I have got a fault code come up on the car, I dont know if it is because I ahve just vagcom'd it with a new version?

1 Fault Found:

00537 - Lambda (Oxygen Sensor) Regulation

08-00 - Control Limit Surpassed

I changed the Lambda not that long ago due to it throwing the same code, the fuel light had just come on when I was running the car dont know if low fuel effects it

I managed to get the measuring blocks done on the car, i took them at just off the needle, 70 degs and 80 degs

[montez]

I have just pulled the wastegate off and i cant see any signs of problems I have noticed that there is a stain on the join between the hot side of the turbo and the exhaust manifold (see picture) would a slight leak here be causing my problems?

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[prj]

Your lambda trims are WAY off (160!).

Check for massive leak between MAF and turbo or replace MAF.

[S2central.net]

channel 8 is way off alright... lines up with lambda fault code... strangely channel 2 is in spec for warm idle though... wouldnt hurt to try another MAF though - try before buy !

[montez]

Yeah MAFs are pretty steep so I will put a post out to see if there is anyone within my vicinity who has one I can try. As for a leak between the maf and turbo there is nothing as it has a silicon hose and all been pressure tested.

I will double check the maf voltages and resistances with the data on s2central to see if it is in spec

[prj]

The fact that lambda trim is 160 means that very likely you are running way lean.
It can be also the fuel pump or FPR...

Good idea to measure fuel pressure, should be around 3.5 bar at idle.