I've been thinking about getting one of the DIY CO analysers as sold in Halfrauds.
I think they are made by Gunson.
Has anyone got any experience of using these?
Are they any good?
Accuracy?
Are they good value?
Where is the best place to buy them?
Etc, etc.
Thanks

I have used one for rough setting of idel CO for mot's etc but they are only desgined for setting at idel not with engine reving,

They don't do lambda or hydrocarbons so are no good for cars with a cat. I managed to blag 1/2 hour in 2 different garages to set mine up prior to SVA.

this is the one I was thinking of:

ive got the older version of that but its a bit of a pain you have to leave it running in air to calibrate it and once youve used it leqave it in air again to clear itself ,pretty accurate for co though ,set my kitten to 3.5%co at idle and it was the same on the mot gas analyser

out of date mot gas analysers are quite cheap on ebay.

Paul

Yellow ones are NBG like most Gunson stuff the quailty pretty poor they must cost about 2 quid to make. Have't tried the green ones.
Having said that they are accurate if fragile -- look out on ebay for an old garge gas tester cost you less to buy.

Other thing you can do is fit an AFR gauge using lambda sensor. Always some on ebay or try Jaycar electronics -- Australian but expanding into the UK, stuff is still sent from Australia but it is pretty cheap.