I had an after-market boost gauge professionally fitted by Zen a month ago to my 1993MY WRX. It works fine, etc.... EXCEPT for when I press the air-con button in to turn it on!

It seems that when the air-con pump is running, the boost gauge drops to the very bottom of the scale i.e. its lowest negative value (which I think is ether -0.8bar or -1bar). Why would this be?

It's especailly weird, as my car is also fitted with the factory option boost gauge (together with 'volt' and 'ambient air temp' gauges, below the stereo), and that boost gauge works perfectly - whether air-con's on or not!

Am I to believe it's a possible electrical 'current draw' issue?

Any ideas people?

Thanks, John

 

Anyone?

 

Hmmmmmm...sounds like the gauge is wired off the a/c supply. Does this only happen at tickover or does it do this when you're on boost too?

You don't say whether the gauge is electronic (not hard plumbed into the turbo outlet) but i'm assuming it is. Is the factory gauge also electronic?

If they are electronic i'd run a new supply from the ignition (outlet side), alternatively you could loop the supply from the factory gauge.

Before you do this it would probably be a good idea to go back to Zen and complain, there might be an issue with their wiring (bad earth?) or the gauge could be dodgy.

If the factory gauge is good, why are you fitting another one?

 

Main reason is that the std. factory gauge only goes up to 1bar and needed a gauge to go beyond this to monitor any possible overboosting issues (I have a Scott T. 1.1bar chipped ECU).

Second reason is that, being on the A-pillar, the gauge is more in my eyeline and the 1.1bar marking just happens to be at the easily-glanced-at 12o'clock position on the dial (it's a 270degree style, -1bar to +2bar, marked gauge).

Third, they look cool .


Yeah, car goes into Zen this Sat 2nd for a geometry alignment - just had the ubiquitous Whiteline F and R solid d/l's & 22mm arb's fitted - so I'll get 'em to check it out then (if they have time)...