High CO%, No Clue Why, Please Help!!!

[BeemaBoy]

Hi

Finally got around to testing the CO% at 3000RPM today and I nearly fell over backwards!!! The CO% guage on my gastester is telling me that at 3000RPM the CO% is 8.7!!! Is this right??? My Haynes manual says that at 3000RPM the CO% should be 1% +- 0.5%. What the $#%^??? Please can someone tell me if I am missing something here. Have I somehow mixed up the conversion? How can my car be over 7% higher than it should be??? It does not smoke at all. If the car is running at this high CO%, Im a big contributor to those green house gases

Thanks

BeemaBoy

[Templ8e30]

Blocked air filter ?

What about the Hydrocarbons ppm ?

Cheers,

Iain T

[lemans]

If the air filter is ok and you dont have a misfire,try checking the resistance of the coolant temp sensor. should be 2100 to 2900 ohms when cold and 270 to 400 ohms when hot.


Lemans

[BeemaBoy]

I have no idea what the Hydrocarbons are as the tester does not show it. The cone airfilter is clean and from what I can see free of any debrit. As for the coolant sensor, I replaced a few months ago.
Did try a test today though , set the AFM to give me a very lean mixture so that it was just above the backfire point aswell as engine stall point and the guage started jumping around 6 - 7.5CO% . I really think that the tester has somhow drifted or Iam calibrating it wrong.

The unit is a Gunson Gaster (Analog one without pulse pump). I did not get any instructions with it and I am kinda messing with it as I go. Has anyone used one of the testers before and can talk me through the correct procedures for the instrument.
As far as I know, you leave it to warm up for 8 minutes and then calibrate the CO% to 2 as per the environment. I don't know what a little switch with a white dot next to the balancing knob does, with it pushed down on the white dot side, the needle just swings round to a symbol on the display called 'check' and when I switch it back, I can calibrate it to 2%CO.

It would be a big help if someone can point out a flaw in the way Iam using this instrument ???

Thanks
BeemaBoy

[kevin316i]

Having the Gunson calibrated right is key.

As a benchmark, maybe you could get a gas test done at a local garage, and then test your CO with the Gunson and compare values. If they are very different, it would point to the Gunson being wrong. Unless the garage equipment was out of calibration.