I got my 94 850T last night, everything is pretty much mint on it except for a cam cover bolt that needs tightening, the odometer needs a new plastic cog thing and the boost gauge has stopped working.

The first two I knew about prior to purchase but I only noticed the boost gauge on the way home last night. The needle just sits between the black and white lines yet I know for certain the turbos are working perfectly.

What could be causing this? I have tried looking on here and came across the only similar case where someone said the O2 sensor can cause boost gauge to stop functioning? is that correct?

 

To best honest with you, forget about the stock boost gauge. Buy an Autometer boost gauge from Egauges and a single or double or triple pod from http://www.gaugepods.com

Money well spent for an accurate boost gauge.

 

I doubt that a faulty O2 sensor will affect the boost gauge. I would double-check the vacuum/boost hoses between the throttle body and the firewall.

I wish that I had a photo/diagram to show you.

 

Look up under the dash to the back of the speedo cluster. You will see a vaccum line going to the cluster. See if it fell off.

Also you should be able to see it but not get to it by reach.

Also TIP: try to look with the car running. If it is off you will hear the Vaccum from the line.

 

Thanks, will have a looksee tomorrow night.