I want to fit an MFD to my car, like what is on the Dune, the Sport, and the GT, so I can get MPG readouts. Is this possible? I'm sure I found a guide for this before, but I'm drawing a blank at the moment trying to find it.

I have a cable for the VCDS stuff, but I don't know which parts would need replacing, and what needs wired up etc.

First Welcome to the forum.

You'll need to replace the speedo unit, which will involve re-syncing your engine ECU to the new speedo for the immobiliser, then you'll need a new wiper/indicator stalk with the select/reset buttons and wire that to the speedo connector

As above, you may also need things like brake wear sensors, washer fluid level sensor and possibly an extra temp sensor.

Thankfully it's not so difficult on the 9n/3 as the majority of the wiring is there so would only need to add it from the sensors to the bulkhead connector. All the wiring diagrams are available so not so difficult.

The main part is getting the immobiliser working. I have tried many times with these cars and spent a lot of time and money trying to do it myself with no result. From what I can tell most of the speedo units are a different system to those used on say the golf or Passat etc which have been covered many times and most cheaper interfaces can read them, but not the polo ones.

If I was to try this again, I would deffinatly give the programming job to a professional. I have a guy I go to for these things and he charges £50 for most things, which is a bargain if you ask me. If you get more keys made up with blank chips inside, then they can program them at the same time for no extra charge which is great as doing that alone usually costs £50. Have a call round, most auto electricians now have these tools and if you bring the car to them they are usually better priced.

Get the speedo unit working with the car first, then if need be you can add the sensors etc, but the switch will deffinatly need to be wired in, which from memory is only 3 wires from main connector to speedo connector.

You can add the switch before fitting the new speedo, this shouldn't effect anything on the old clocks but means that when the new one is fitted you will have the buttons ready.

Well the car doesn't have a remote key, as it's a pretty old fashioned 9n. Are there any 3rd party alternatives to get mpg readout a?