Average MPG on LCD not working

[Hammy-GTX]

Pretty much says it in the title but all the other functions work just the MPG says 99.9, and as its probably the only one I would really find useful I would like to sort it out

Alex

[ianaudia4]

The MPG is vacuum sensitive, so first port of call would be check your vacuum hoses, especially the one that goes into the back of the inlet manifold, on the throttle body, if they look old then change them, usually about a fiver for a metre length.

[Hammy-GTX]

Okay ill give them a check thanks.

[mark1gls]

There is also a hose which goes from the brake servo to the inlet manifold, there should be 2 pipes coming from it, what usally happens this the end on the pipe gets broken as they get brittle with age and the pipe is no longer sold by VW so it's hard to get hold off (unless you can find one lurking at a VW dealer)

Check both pipes are there, (2 pipes running under the accerator cable) Yellow pipe is for an enrichment valve (you may not have this) the clear one in the photo is the one which goes to the MFA for the MPG. The black bits on the end of the pipes are what ianaudia4 said about replacing.
The photo is from my Mk1 Golf Cabriolet 1988 so might be slightly different but you should still have a pipe there going through the bulk head onto the back of the speedo.

[bluestreak56]

viewtopic.php?f=11&t=11012&hilit=+mpg

[Hammy-GTX]

That picture looks exactly the same as my engine haha I think the black bits on the end are a bit ropey, ill try and change them. Is it difficult to get to the back of the clocks because I might just check if its even connected!

[ianaudia4]

Easy to get to the back of the clocks, just take the module out of the dashboard!

[mark1gls]

Not sure if it's possible on the Mk2 Scirocco but try removing the cover above the pedals and you might be able to see the back of the dash from underneath with a torch, you might need to take the drivers seat out (1 bolt at the front and remove the covers at the back and side the seat out) or push the seat all the way back and try to lye on the floor to look up towards the dash.

[ianaudia4]

Much easier to remove the steering wheel (24mm socket), take out the 2 screws on the binnacle surround and then remove the 1 screw holding the clocks in place, remove both plugs and speedo cable (push together the clips) and the clocks can be pulled out and then you will see the vacuum hose. If your dash bulbs are blown as well it is the time to replace (still available from the dealers).
Just be careful with the blue PCB, as it is fragile.

[Hammy-GTX]

Ill have a peek at the back of the clocks them because the other end of the vacuum hoses seem to be okay...

[bluestreak56]

Had 3 of these go on me, was always the speed sensor..

[Hammy-GTX]

Wheres that situated?

[bluestreak56]

Sorry just realised my link above is no longer working..



Orange circled part on the right hand side. It is a part that you can remove and replace quite easily without ruining the clocks..

[Hammy-GTX]

Thanks for your help I'll whip out the clocks and see whats what..