Boost issues.

[A90TURBO]

Fuel pressure reg?

[Jas11n]

Thanks for suggestion all. At this stage I'm not ruling anything out.
I'd not be in the least bit surprised if it turned out to be a blown sidelight bulb

is it worth having a look at the cats? i know you replaced them recently but wonderd if they might have broken down?

Hmm, good thought. I'll take both off and have a look.

Absolutely sure its air tight including PCV system ?

Yup, as tight as me.

Jase,

Is it possible that the cutting out was due to an immobiliser fault in your original ECU or key reader and that once you changed to your non immobiliser ECU you lost the cutting out fault but gained the boost limit issue due to some wiring incompatability/country code sort of issue from fitting a non immobiliser ECU into an immobiliser loomed car.

Sorry if it's a rubbish suggestion...............

John

I still haven't ruled out an ECU problem Johne. It keeps on rearing it's head when I'm pouring over the possibilities. I'm going to try my bro's immo ECU at the weekend. I'll need to match it to mine, but that's easy enough in vag-com.

Fuel pressure reg?

Would low fuel pressure limit boost constantly to 0.4bar?

[A80Avant]

if you want to try out an FPR i have a new one 4bar

[macspring]

Jas11n,

Not worth anything I know, but I feel your annoyance with it.

Wishing you and it a speedy recovery.

It will be interesting for all to note what it turns out to be, when you nail it.

Good luck.

[S2central.net]

I doubt its an FPR issue - if it was low pressure and therefore running lean enough to cause excessive knock at high boost (which in turn results in active boost shutdown) - it should also be throwing up mixture adaptation faults on the ECU. You do have to hate these cars sometimes... But then if they were as easy to work on as a Ford Fiesta then everyone would want one

[s2_bo]

Just another thought, could it be that the WGFV even though new is not working?
I recently bought on from audi and it turned out to be dead. Had it replaced and now its fine..

I doubt its that but maybe worth a try.

[Rusty]

Sounds like wiring as you've replaced all the sensors. I had a plug go funny and had na intermittent starting issue, it was the crank position sensor. Might be worth wiggling a few of the connectors at teh back of the bay and seeing what happens, otherwise take each plug apart, check it and re-assemble, might cure the problem like I did...

[Paulgo]

Hope you get it sorted matey - and these sort of problems do get ya down when you just cant get to the root of the it! Got to be one of the things you've got left to try and sure you'll have her back to best by the weekend

[Error404]

Hopefully you went direct to Bosch for the knock sensors Jase as per the OEM parts thread? - 1/3 the price of the stealer

I've no experience of motronic faults but had a knock sensor go bad a while ago on the CQ without any fault codes or owt, started with a bit of chugging occasionally, and then developed into the whole rev range becoming a flat spot

Hope the knock sensors sort it, and at least you'll have loads more good spares once its sorted

[alg]

My wire to the WGFV broke in the plug. This gave 0.4 boost & intermittent full boost & clicked when tested initially. Then Mihnea played with it enough to make it fail & Doug soldered it. Any help ?

Or you could come & look at my lovely RS2 & make an offer !!


Oh & no codes on vagcom.

I am going to miss all this

[mcandmar]

I doubt its your issue but check the ignition switch at the key. I had one go faulty and would cut the engine if the key was wiggled around, hitting large pot holes or speed ramps too quick would also do it with the weight of the key ring hanging from it. Would explain the random cuts, and difficulty starting.

[alg]

Is it sorted ??

[Jas11n]

Is it sorted ??

Just about to update this Alastair.

In a word................nope

In addition to the above, I've had both cats off to see if maybe the matrix had broken up blocking the exhaust, but they are fine. I've replaced the rear knock sensor to no avail. Hopefully this afternoon I can get on and replace the front knock sensor, which is a bit of a pain to get to, but I've got the top rear rad hose to replace with a new one, so should give me a few more nano-millimetres to play with
The wiring to the WGFV is fine, it's been buzzed from the ECU with lots of wiggling and so on to see if it could have had an internal break in either of it's two wires.

The wastegate diaphram has had vacuum applied to the top and it holds that vacuum fine, so it's not split.

I've taken to calling her the "Byzanz Bitch" at the minute. Allie (GF) reckons she's in the huff as I use the TDi more.
I would care, she's driving brilliantly apart from this no boost issue. Had the clutch master cylinder changed yesterday cos that pesky rod bent and the pedal was getting REALLY stiff and sticking down at times.

I 'may' end up having to drive down country to see someone like Tom or Doug. The corner I'm in is getting a bit claustrophobic

Forgot to add.
In not wanting to overlook the obvious, I've had the hose off the coldside inlet of the turbo, and the wheel spins freely and doesn't have any excess movement either side to side or in and out.

[Jas11n]

Replaced front knock sensor with a new one, still no boost above 0.4bar.
In fact, she'll not boost beyond 0.2bar most of the time.

I'm at a loss now. I've changed everything possible bar taking the engine out and giving it a good kicking

Is there any way I can "briefly" force it to boost to rule out maybe damaged hotside blades of the wheel . I don't fancy taking the turbo off just yet if there's an easier way first.

[s2_bo]

What a pisser! sorry to hear this Jas, nothing worse then poring money in to the car with no change.

I did that on my rs2. Replaced all the wheel bearings one by one to try and stop the sound but it turned out to be the brakes sticking.!

Best of luck !!