We're on the same page dd, That's exactly what I said to the mechanic, but he reckoned I wanted to keep them closer to 12.5-13 for a safe tune. the exact quote was: "you will probably drop a few hp, but if you keep running it the way it is it may cost you an engine"

What do you mean by lean?
Quote:That's rich. Stoich is 14.7. 13-14 is rich, but not overly so. 15 would be lean. See air fuel ratio encyclopedia entry:Quote:

The colortune says rich, right through the range free revving (bright orange flame), but I just had my car dynoed and I was running up to 13.5-14 AFR from 4000rpm up when it was under load.

Lean through the top end just as I had suspected from the start!!!!!

And I was about to get smaller jets based on the colour tune Damn thing could have cost me an engine (or at least a valve or two)

A-15 dyno sheet

Yeah, sorry, bad choice of words there. It is rich right through the range just reving it (not under load)

They warn against prelonged use, because of the heat range of the plug. I cant remeber off hand if it was hot or cold so I'll take your word on that one.

But apparently using it on a dyno is okay -just in case you have a dyno but no analytical gear to go with it

so potentially you could do a quick run around the block with the bonnet off and the little viewer scope pointed towards the driver .

Hi Grunterhunter, how do you use the Colortune spark plug to check the entire engine range? I thought you couldn't drive around with it in the engine since the plug runs much hotter than the normal plugs.

My gunsson's arrived on the weekend
Man that thing is cool.

turns out I am very rich right through the range.

Are you talking $400 US?

That's about 650 australian paseos, which is a pretty serious % of the value of the car!!

you can get an ok wide band 5 wire o2 meter for under $400. It's much more useful than the ones that are 1 or 2 wire and cost $150.

Lambda sensor was my next question But I didn't want to put it all in the same thread. I have heard mixed reviews about them, from "they're great best tune up tool ever"- to "complete waste of time, too many variables, dont compensate for temperature properly, proper mechanics ones are $5000 for a reason- a $200 O2 sensor & gauge is just a waste of money"

and probably more convincing negative arguements than positive ones

I second the wide band 02 sensor. the color tune is really not going to be easy to make work in a setup with a digital camera. You could also get an EGT gauge but it's not as straightforward as the 02 sensor.

maybe we all should bite the bullet and go to the dyno every year or so and get a real good tune. I think that's what i'm going to do, just make 1 big trip to the tuning shop and have it all done at once, get it on the dyno and optimize the AFR, then align and set camber then tweak the ride height and corner weights, probably won't cost very much and then everything will be perfect.