May 01, 2014 In the owners manual for your car there is a spec for%CO in the exhaust gas at idle. The Gastester allows you to make that measurement at home without having to take it to a shop with a gas analyzer. They cost about $200, but often less, and are accurate enough for this purpose.
![Gastester Gastester](/uploads/1/2/5/8/125852741/963713404.jpg)
Senior Member Location: Left Coast, Canada | First of all, I'd like to thank all the Gunson Gastester owners who contributed tips, and got me on the right track. There is a nice little booklet that comes with the tester, but of course it doesn't tell you *everything*. This sums up most of what other users have recommended, plus a couple of points I found out myself: 1)- *****-can the plastic hose (for the sniffer probe) that comes with the unit. It's way too short, and as such, melts under the heat of the exhaust. You don't want the head unit anywhere near the tailpipe while testing anyway. The head unit must be sitting in clean air. To this end, I used a 10' piece of 1/4' ID rubber fuel hose. It resists the heat, even for a long testing period. 2)- The Gastester gives accurate and repeatable readings *if* and only if you warm-up and calibrate it correctly. I advise powering it, not from your car's battery, but from a separate 12v battery. That way, you can let it warm up on it's own, while you go for a drive, warming up the car motor. I let the tester warm up for a full 1/2 hour. More time than the instructions asked for, but this made for a very steady reading after calibration. You are not supposed to move the head unit after calibration, and I didn't try. 3)- After the testing period is done, the instructions suggest leaving the probe in clear air for 10 min or so, unit still powered up. This is said to purge and clean the unit's sensor. You can tell the purging is done, when the display returns to the 2.0% calibration figure. I found this took much longer than 10 min. More like a 1/2 hour. But it's no problem to leave it running as long as it takes to do the job. 4)- The so-called 'Automatic Water Drain' doesn't seem to drain squat! There is quite a bit of condensation that collects in the probe hose, but it didn't seem to affect the reading. I just poured it out of the hose after the testing was over. While all this seems like a lot of fooling around, just to get a CO reading, I was very pleased when I compared my results to a professional Sun 4-gas tester. The Gunson Gastester is certainly accurate enough to help me tune my motor for performance, as well as emissions at smog check time. __________________ '81 SC Coupe 'Blue Bomber' 'Keep your eyes on the road, and your hands upon the wheel.'- J.D.M. | |
03-16-2003, 06:06 PM |
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