All your other cars must have been magical! They got their EPA rated MPG at 80 and always read the correct temperature!
THey performed as advertised. What can I say?
Every single car I have ever been in has this problem. The local temperature in a parking lot is usually going to higher than the "official" temperature of the area. Even if you're parked in the shade and especially if your car is still warm from a previous drive.
What cars have you been in? Corvette, 370Z, Jeep were the last 3 I had.
Having said that, once my car is driven at speed I find that my temperature reading is usually withing 2 degrees of most outdoor temperature displays (banks ect.)
If your car is still off by 5 degrees when your car is being driven at speed than your temperature reading definitely performs worse than mine.
Here's what the temp sensor reads according to the service manual. I think the two lines might be the possible range of readings? If so, than the margin of error is very large and could definitely explain your 5 degree offset. The sensor is located behind the front bumper and as mazdadude said, you could definitely connect a resistor in series with it and fix your offset. I would recommend using a variable resistor so you can calibrate it on the fly after you've attached it.
I can see the location of ambient temperature sensor on CX-5 could be problematic as it's right in front of AC condenser and radiator. The same sensor on our VW and BMW, although behind front bumper, all located very low near the belly-pan and away from condenser and radiator.Here's what the temp sensor reads according to the service manual. I think the two lines might be the possible range of readings? If so, than the margin of error is very large and could definitely explain your 5 degree offset. The sensor is located behind the front bumper and as mazdadude said, you could definitely connect a resistor in series with it and fix your offset. I would recommend using a variable resistor so you can calibrate it on the fly after you've attached it.
Now that I know where it is, it makes sense. Dodge, chevy, and Nissan put their sensors in smarter places and this is the first I've seen it.
I'm not going to mess with it. Sorry you have issues with believing that some cars actually DO perform as advertised. What's interesting is that when I posted my MPG results on the various forums, that was about what everyone else was seeing, as well. Some saw 1-2mpg more, some saw less, but most said that's exactly what they got under similar circumstances. Of course, herd mentality is far from scientific, but it seems good enough for this forum, so I'll go ahead and cite it, lolThat's really something! (bs)
So, tell me more about what you know about my personal experiences? (It typically averaged around 17.5-18.5, but coming back from New Orleans, it did exceptionally well).
I've had a lot of thermometers in my life and the curious thing I've noticed is they tend to measure a combination of the air temperature and the objects around them. Put them in the sun and they go sky high. Put them near a hot engine and they measure the heat radiated from the engine. Who woulda thunk? (shrug)
Indeed, indeed. Somehow my Nissan and Jeep always nailed it, though. The Corvette was always garaged, so I can't much fairly say. If I wasn't driving it, it was in the garage.
The thermometers in banks in my area vary by up to a 8 degree range on a hot day. I can drive by 3 of them in 4 minutes. It's rare that they all read within 3-4 degrees. My CX-5 is all over the place too during hot days depending on how hot the asphalt under the car is, whether it was parked in sun or shade and which way the car is facing relative to the sun. This is to be expected. When the temperatures get in the 30's and I'm not driving in heavy or stop-n-go traffic, it settles right down and does the job it's supposed to (warn of potential ice).
Crazy that it varies so much on the CX-5. Never experienced that. I have double-checked with weather.com when I see bank signs though, and I drive almost exclusively at night, so I don't think sunlight/shade is the issue.
Of course roadway ice can form when the temperature is well above 32 degrees under certain atmospheric conditions so temperature is just a general guideline.
For sure! About 34*F is when I reliably saw it on bridges where I used to live.
Variable resisters can vary depending upon temperature and are not as stable as most fixed resisters. If the thermometer really does need calibrating, it might be better to use trial/error using a selection of fixed resisters. But it's never going to be perfect due to the effects mentioned above. Well, unless you have a magical car. (whistle)
