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I made it to Spain this time and the car was faultless but after being parked up for a week I got the p0491 and po492 error codes. I cheated and used ultra gauge to clear them and it hasn't reoccurred, checked as much of the hoses as I could get to with a limited tool kit and nothing seems untoward. These codes have never come up before, just coincidence due to average temperatures of 30c + or an intermittent fault that will manifest itself in due course?

It probably had sunstroke after being subjected to good weather

I would feign ignorance and see if they reappear.

My thoughts as well but with a bit of a language barrier here, I'd thought it best to ask.

Bank one and two errors. So probably not the valves themselves.

Maybe a vac leak, but then I'd expect rough running. Can you check your trim?

Maybe the pump is weak and not flowing enough air. Maybe the low density air / hot conditions means the effect of the SAI dipped under the threshold for performance.

I'll see what I can get ultra gauge too do, if not then I'll use VCDS. There is no rough running and it hasn't happened again......surely there should be a fingers crossed or touch wood icon?

It won't run rough - SAI is only used during initial startup. I've actually removed all the gubbins for it and removed it from my ECU entirely.

To clarify: if there's a vac leak it'll run rough (unless tiny leak).

Did you blank off the SAI valves?

Yeh - sorry. I just meant if the pump's failed or the valves stuck shut.

In my case, yeh, all gubbins removed and I put a blanking plug direct in to the heads. So now no longer sounds like a cheap hairdryer when you start it up, plus cleans up the back of the engine and makes it a "little" easier to get access to that end of things if I need to. Still got all the parts "just in case" though. I have a stock or maybe even a Stage 1 tune with SAI coded out if anyone wants it - you do still need the relay & solenoid (but not the motor) to be electrically connected though, never quite got round to finding the bits I needed to set to remove the readiness check.

(To be clear, I'd ONLY advise using a non SAI tune with the valves removed & blanked off - however I think this should be possible with a little jiggery pokery with the motor in situ)

That's what I was going to ask... how did you remove the SAI valves? I had a look when doing my engine the other day and they looked like a bugger to unscrew without removing the engine.

You won't get the RHS bracket off the head without removing the coolant pipe - but I reckon you could leave the castings attached to the heads and just remove the valves that are bolted to the top of them - they each have (IIRC) a pair of 4mm (M6 thread) socket head cap screws on the underside of them which I think you could make a tool to undo. Don't quote me on that though, I had my motor out at the time and am trying to keep the bonnet closed at the moment pending this winters DRC removal project.

(FYI to anyone looking to replace DRC - Koni are out of stock of the 82-2516SPORT front dampers at the moment and they're on a 6 week lead time).

MattV8 wrote:they each have (IIRC) a pair of 4mm (M6 thread) socket head cap screws on the underside of them which I think you could make a tool to undo. Don't quote me on that though

Ha ha!

Yeah, that's what I observed. Still looks like a nasty job, though, resulting in lots of skinned knuckles.

Suspect the standard blanking plate every man and his dog uses for 1.8T SAI deletes would fit. Did you make your own?

Apparently they do fit. However I noticed that the hole size in the head was about right to take a 1/4 NPTF thread, so did that and screwed some bungs directly in. Which I think I read somewhere is what Unit 20 do.

Is the default position of the SAI valves "closed"?

I didn't actually check.