The Simps

I believe the unit on the right is the water pump but would like confirmation. Also what is the item on the left please. Thanks in advance.

The Simps

Actually the one on the right turns out is a component of the LPG system! So just one on the left please.

twentysevenlitres

It's the secondary air pump.
Part of the emission control system.

The Simps

Of course! Thank you. 1st time I've been under the car today. I was surprised to find the air ride compressor in the wheel arch, I was always under the impression it was bolted to the engine.

twentysevenlitres

Forgive me if you're talking about something else,
but the secondary air pump is used to blow clean air into the exhaust system to help burn any unburned fuel and clean up the remaining gases to produce cleaner emissions.
I'm not sure if it's added pre or post catalytic convertor? I would suggest pre, but downstream of primary O2 sensor.

MN-A8

Close but not quite. The SAI Pump is used to warm up the cats at startup to help with emissions control. It actually blows air into the exhaust side of the heads through a valve. This extra air helps get the cat up to operating temp faster.

The Simps

So does a malfunctioning SAI have any effect on how the engine runs? I assume not as in goes in exhaust side.

MN-A8

Depends on what part of the SAI is broke. You might experience a rough idle at cold start up and then nothing after that. Scanning the car should be able to tell you whats not working.

The Simps

Please see my other thread if you have a moment - https://www.audiworld.com/forums/sho....php?t=2851419