Just fitted a boost gauge in to my scooby dont know what ive done wrong powers up but on idle it is reading -0.6 bar also when i turn my headlights on gauge shuts down, if any one could shed some light please do.

 

Rofl there's nothing wrong with it, it's working perfectly.

At idle you get vacuum in the inlet manifold (because the engine is trying to suck air past the closed throttle plate). When you turn the engine off, the engine stops sucking the air so the vacuum disappears.

You'll only see positive pressure when the turbo is actually making boost. Immediately as you lift off the throttle you'll see even greater vacuum - nearer -.8bar or so.

As to the gauge shutting down when you turn the lights on, is it an electronic gauge? If so sounds rather like you've connected it incorrectly. Need an "ignition on live" to power the meter itself plus dash lighting for any illumination.

 

the vacum gauge can be used to read engine faults also eg. worn vlaves etc do a google on how to read a vacumm/boost gauge its amazing the things a vac gauge can point out if sumfin goes wrong , good bit of kit

 

Thanks for the insite it is an electonic gauge, 4 wires 1 permanant live, 1 ignition live, 1 illumination taken from dipped headlights, 1 ground. Not sure if i should have taken feed from headlights??

 

Not meaning to hijack the thread but is this where you T a boost gauge in ?

Marked in red in my pic ?

 

That is where the t-peice is it had this on already there was just no power to the gauge.