Knock sensor help please

[Human Joist]

Will do mate. Changing the plugs now. Will spray all connections first and try it again. It shows it as an intermittent fault. The fact I can’t find anything on these forums lends me to believe they don’t normally play up

[Shoppinit]

Yeah, I don't remember coming across a failure before. You must just be lucky.

[Human Joist]

[Human Joist]

While you're in there you might as well replace the suction jet / non-return valve which has a tendency to expire causing all sorts of vacuum misery. Test the after-run coolant pump, too. If it's dead (they die discretely) you can replace that, too.

This valve should I just get it off eBay or do I need to look at genuine. They appear to only be £8

[Human Joist]

By way of an update. Inlet manifold off. Lovely job . Faulty knock sensor ordered. Jet valve pipe ordered as it broke coming off. Secondary coolant recirc pump didn’t work when tested so ordering one tomorrow along with new inlet manifold gaskets. Then will start and put it back together

[Shoppinit]

Why are your DVs connected together?

[Human Joist]

Hadn’t touched that pipe work. What should they be connected like then ?

[IchBautAuto]

Hadn’t touched that pipe work. What should they be connected like then ?

These are alloy DV and I've changed them out for GFB products but you can just see the vacuum pipework, marries and then to the vacuum source. 7zap or the equivalent should give you the actual pipe layout.

[Human Joist]

Ok. Clearly this set up is wrong on mine then I don’t have access to any manuals for how it should be. If you have could I ask you drop some images on so that when I stick the inlet back on I can ensure the correct flow for the vac lines. What would be the cause of them being out on wrong. Will it damage anything or just stop it working correctly

[Shoppinit]

The Bentley manual is pretty good.

https://www.amazon.co.uk/Audi-A6-C5-Ser ... 0837616700

[Gregstv]

Interesting that your after run pump is mounted on the engine. The one on the spare engine I have is mounted on the under side of the inlet manifold.

[Shoppinit]

The DVs definitely won't be doing what they are supposed to be doing so your turbos will be being brakes by the throttle valve when you lift off. Probably won't cause any damage, but you'll effectively be losing performance.

Makes you wonder where the plumbing that was supposed to be going to them is going, though. That could be a source of problems. Biggest concern is probably vac leak.

[Shoppinit]

Interesting that your after run pump is mounted on the engine. The one on the spare engine I have is mounted on the under side of the inlet manifold.

I wonder if it's because yours is the other type of cooling circuit. Do you know your production month?

[Human Joist]

Ok. Here is the set up at the moment. Will buy a Bentley manual too

[Human Joist]

Could you show us where your pipe work goes please ? As after the meet they then t off. Just wondering if the connection is just further along on yours