Has anybody ever seen or done a study on the accuracy of gauges in automobiles, or know anything about their tolerances? I'm not so much talking about odometers (e.g. the recent Honda lawsuit settlement) and fuel level gauges. I'm talking more about tachometers and redline, water temp, oil temp, oil pressure, voltmeters, even fuel economy gauges. I assume it could vary significantly from maker to maker, and from mechanical to electro-mechanical to electronic. But I wondered if there's a specified maximum tolerance by SAE, automakers, etc.
Accuracy of auto gauges
- Thread starter LouDawg
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Most electronic tachs on cars have some delay in my experience. It's largely irrelevant, though, since 90%+ of cars have automatic trannys in this country. As for fuel gauges, I think every manufacturer pads their gauges to a greater or lesser extent so that you have a buffer when the gauge gets to E. Water temp gauges are notorious for being padded, too, so that Joe Public doesn't freak when the gauge starts moving around.
Well my Toyota Camry has been right on interms of speed when checked against my GPS.
When my fuel gauge reads empty and my low fuel light comes on, I have a gallon and a half left in the tank (tried this and filled up a 14 gallon tank with 12.5 gallons).
Unless they made it smaller after 1998, the cavalier/sunfire tank is 15 gallons.
I have a scangauge and can see the inaccuracies and worthlessness of most every gauge except speed. Thats pretty close to what the computer reads until 70+; then it reads low. I know pretty often oil pressure gauges are fake. Below Xpsi the gauge is red and above Xpsi the pressure switch closes and the gauge jumps to middle of the range. Junk.
I have a scangauge and can see the inaccuracies and worthlessness of most every gauge except speed. Thats pretty close to what the computer reads until 70+; then it reads low. I know pretty often oil pressure gauges are fake. Below Xpsi the gauge is red and above Xpsi the pressure switch closes and the gauge jumps to middle of the range. Junk.
Speedometers, odometers, and tachometers, are not NASA spec accurate, but are generally pretty close, nowadays.
Water temp is usually in the middle of the gauge, and needs a 40 deg F difference to move. They don't want to alarm the average citizen.
Voltage is usually right on, as well.
Oil pressure gauges seem to be on/off, rather than a real reading.
Water temp is usually in the middle of the gauge, and needs a 40 deg F difference to move. They don't want to alarm the average citizen.
Voltage is usually right on, as well.
Oil pressure gauges seem to be on/off, rather than a real reading.
Do you have a specific car in mind? A lot of Ford guages for instance are simply idiot guages (light disquised as a guage). They read somewhere in the acceptable range and stay there until something drastic happens.
Alex.
Alex.
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