Spark plug mixture tool thingys!

A guy a work has told me that you can by a glass spark plug tool that allows you to see the colour in which the air - fuel mixture is burning.

Has anyone ever heard of or used such a device?

Cheers

Gareth

Its a Gunson Colourtune. You can get them in Halfords for around a tenner. I have one but havent yet to use it much yet, only my brothers Polo and my old Mini. It sorted his emissions out for the MOT and I think its pretty nifty  

I've used it before on a few carb engined cars I've had and it seems to work pretty well.

For a few quid more you can get a Gunsons exhaust gas analyser which takes most of the guesswork out of the emissions side of things. Not used one myself, but have heard they work OK.

I have a Gunsons CO Meter - works great, always helped me through the MOT when I lived in the UK - Only accurate to +- 0.5% CO, so not great for late model cars (tighter emissions rules make 0.5% too big an error to work well - but they have engine management to check the mixture 200+ times per second!)

Perfect for GTI's and carb-Golfs

The Colourtune is a fine (and cheaper) option too - go for it if you can't afford/don't want the CO Meter.

Thanks guys i will give it a go, will post how I get on.

Gareth