I am beaten

[Rikki Kitto]

Yes, the written text over the internet can be very easily misinterpreted, especially when it transcends languages, locations and cultures -it is why I always err on the safe side of keeping it very polite.

Well said young man I for one have had lots of help from this forum and of course get second opinions where possible maybe the man can't afford to take it to a "professional" that's why he's asking for help on here, if you have the answers just let him know rather than pulling apart others who are trying

[twoqu]

Lets get back to what we do know!
The OP had both Lambda codes, 00525 & 00537. The car starts and idles perfectly for @2 minutes then seems to run rich. The OP has changed the lambda due to the codes and there is no difference.
Had we got the other supplementary part of the codes that might have helped and as always there is no certainty that a code is the actual fault or just indicative of another symptom.
So the 00525 code could be any of the following:
Faulty lambda (Been replaced already)
Wiring fault either signal or heating circuit.
Ignition issue plugs/coils (new plugs).
Fuel pressure.
Air/Vac leak.
Exhaust leak.

So 00537 code could be any of the following:
Lambda (New)
Power supply to Lambda
Ignition issue
Fuel pressure
Air/vac leaks
Exhaust leaks
N80 open/leaking.

Some of the these faults would only apply to either rich/lean conditions.
So we can start to eliminate some of them. Some we can test some we cannot unless you have the gear. So what can we test with a multimeter and a pair of eyes and a mouth!
We will have to assume that a new Lambda is operative.
So next step is check the wiring to and from it. Remove the signal wire from the sensor to ecu and check for voltage from the wire to the ecu and a good earth with IGN on. It should be 0.45-0.50V. Next check for voltage at the heating connection by again disconnecting it and probing the two terminals. With the engine running you should have 12+V.
Next I would perform the output test on the N80 as this is easily done through VCDS. If it clicks then thats a good sign. The N80 could give all kinds of issues. If it was stuck open with the engine running then the engine could draw the fuel vapour from the tank. There is some confusion over whether the N80 should be opened or closed without power. At great personal expense I have tested this on one off the car. All I can say is that from the side opposite the electrical terminal you cannot blow through it, you can suck it open. From the terminal side you can blow throw it but not suck it open! The N80 is the blue cannister with the blue connector.
I do not know of any amateur way of assessing the quality of the the ignition system. You have replaced the plugs which leaves the coil/pos potentially.
Obviously fuel pressure would need a gauge.
Air/vac leaks. I believe you have already done a leak test. But were you not looking for a pipework t piece before?
Exhaust leaks, has the exhaust been disturbed or any sign of leakage?

Freely admit to not being an expert. Of course with a fully equiped workshop it might be easier to home in on the fault quicker. I can only suggest testing and eliminating what you can and see whats left. If we knew with certainty what happens to the engine after @2 mins of running then that would be a great help. It seems to happen too regularly to be a coincidence. So don't get disheartened. Post up whatever you discover. You need to start testing and eliminating!

[twoqu]

It also looks like there is some connection between the lambda going closed loop and the operation of the N80.
If the N80 is not powered or inoperative it looks like the engine can suck in as much tank fumes as it can through a non return flap in the N80. The specified resistance is between 40-50 ohms. I measured my one at 46 ohms.
Even if it works through the output test that only proves its capable of being operated as this would be powered by the holding relay in the ecu. When the vehicle is running, power is fed from the fuel pump relay through fuse S24 to the N80. I beleive from recent experience this particular FPR contact also feeds the injectors so thats likely to ok. So another basic test would be to look at fuse 24! Likewise the power for the Lambda heating is also from the fuel pump relay through fuse s25. Might as well take a look at that as well.

[DEREKCO]

I am beaten

Guys i am overwhelmed by your kind response i am on holiday for 1 week starting Friday night you have given me a massive amount to explore ,i have a young Wiz kid with a computer with vagcom on so will be employing his services , its not about the money in finding the fault it's about pride , you are a fine group of guys ,thank you ,i will apply ALL the suggestion and keep you informed ,some areas you have mentioned i have not explored.once again thank you

[DEREKCO]

I am beaten

Hi further to the post's cats are empty i bought them from a forum member last year ,brand new power flow exhaust system as well, fuel pressure regulator just fitted brand new OEM. Exhaust smells of fuel all the time as engine is running

[Bowie69]

Could be a silencer has broken down, so cats empty or not, I'd still do the remove lambda test...

[DEREKCO]

I am beaten

Hi guys again please read all of my posts on this matter also check out my post on spluttering you will find all the items i have replaced on my car all to no avail , new t piece ,is valve , pressure regulator, temp sensor x3 ,pcv valve ,one way valve , spark plugs ,spark plug connector,s ,MAF sensor ,all vac pipes renewed ,finally boost leak check twice and to end lambda probe .Vagcom shows NO CODES initially when the car started acting up ,the code for lambda did show itself that's why i renewed it.

[sidrick]

Well said young man I for one have had lots of help from this forum and of course get second opinions where possible maybe the man can't afford to take it to a "professional" that's why he's asking for help on here, if you have the answers just let him know rather than pulling apart others who are trying

Can't say I agree.

PRJ is just pointing out misinformation in a blunt manner. I like the no BS approach. If the OP can't afford to take it to a professional then it's unlikely he can afford the time and money to follow a wild goose chase of people spouting whatever comes into their head without knowing what they're talking about.

The lists of 'I've replaced a,b,c,d,e,f,etc' that happen on forums on a daily basis can be avoided, and cost far less money, if folk take it (or speak) to someone who knows what they're doing in the first place.

As far as forums go, this one is generally excellent with technical help and advice. The person correcting misinformation shouldn't be lambasted just because he didn't give a reach around while doing it.

[Rikki Kitto]

There's much better ways of putting your point across that's helpful and constructive

[Bowie69]

Yup indeed Rikki, there was also no lambasting, just asking for politeness and a bit of normal human to human respect. Anyways, moving on.

P.s. 'young man', haha, I turned 40 last year

Lambda codes are good place to start, but to me they feel like a symptom of the issue, rather than the issue itself -the car is running pig rich, so the lambdas will give an out-of-range error.

Agree the N80 could allow fuel vapour in, if faulty, may be worth pulling the hose off it and plugging it, try again.

One thing I will say, is with all the advice, make a plan, and stick to it, testing one thing at a time, then putting back to stock when checked out, otherwise you could end up going round in circles.

[s0_big]

How did this story end? I have similar problems.

[DEREKCO]

Mad sensor