CO2 levels

A quick check around has revealed more than one model of Gunsons gastester, the instructions for the one I had can be found here:

and it states that the car under test can be used for the electrical power supply, but to turn off the ignition whilst the connection is made. There is no mention of using a different power source.

David

If you went to the factory, somewhere in Dagenham IIRC you would understand why . However, they were helpful and fixed the problem I had for free.

I doubt it. It's nothing to do with the factory, but design. If it needs a stabilised voltage supply to work properly it should have one fitted.

Given the vast profit margin on their products I'd hope so.

Yes, while doing the calibration bit it was obvious that the reading was drifting about a mean value every time the fan cut in or out. At that point I got out the stabilised power supply, which resulted in a steady reading that was easily calibrated.

Yes. At the time I had two cars of the carburettor/distributor type, and it was a joy to set CO, idle revs, and dwell angle properly for the first time. Tuned up in this way my two oldish bangers with ~100,000 miles on the clock sailed through the MoT with very low emissions.

Terry Fields

Did your unit have those options then, mine only tested for exhaust gas emissions ?

David

Yes; there was a sensor clip to the distributor for revs/dwell measurement.

I found it to be a useful instrument.

Terry Fields

I'm glad you found it useful. I used other instruments for measuring dwell, ignition timing and rpm.

After an hour or so mucking around with the gas analyser not being able to calibrate it, I gave up with it.

David