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post #1 of 9 Old 15th March 2006, 09:13 AM Thread Starter
Frits
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Outside temp sensor

When I had my car for about 6 months, I installed a set of coilovers, and lowered the car quite a lot. The front airdam touched the ground several times, and once, the outside temperature sensor popped out. I just put it back in the hole I thought it came out (couldn't really see, since the airdam is only a few cm above the ground).
Now I notice that the outside temp I read on my instrument cluster increases a lot when I'm driving slow. Last week e.g. I saw 33°C, while it could have been at most 8°C. I can't remember if I saw this same behaviour before the temp sesnor popped out ot the airdam or not.

So, is this normal, or did I probably put the temp sensor in a wrong hole?
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post #2 of 9 Old 15th March 2006, 09:37 AM
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I don't think it's normal mate. Mine seems to display a fairly accurate temperature whether driving quickly or slowly. If you stay in the same place for a while with the engine running and it is very cold outside, there is a chance that the heat from exhaust/engine could warm the air close to the car by a degree or two, but certainly not by the amount that you have seen.

I hope this helps


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post #3 of 9 Old 15th March 2006, 09:40 AM Thread Starter
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post #4 of 9 Old 15th March 2006, 09:45 AM
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post #5 of 9 Old 15th March 2006, 09:49 AM Thread Starter
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To be honest, I tried multiple holes

The sensor fell out again, so I tried another hole, and kept pushing until it didn't come out again. Might have to do it again while I can SEE what I'm doing...
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post #6 of 9 Old 15th March 2006, 09:51 AM
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Hi Frits,

It is important to keep in mind the proximity of the sensor to the road surface. Over here in South Africa mine could read up to 5 degrees celcius difference between ambient and display readout. I have had my sensor renewed before I realised this so my sensor is quite new.

Remember that tarred surfaces in direct sunlight could heat up to 65 degrees celcius and over on a warm day. If my stock air dam is about 25-30 centimetres above road surface, the effect of your lowered suspension could be worsened two or even threefold on a warm day, with having the car at a standstill (say for instance at a traffic light) with no air flowing over the sensor your stated readouts are quite possible.

The sensor in question also controls the climate control system, so if your cc system is working ok chances are there is nothing wrong with the sensor itself. Your erratic readouts might be as a result of the sensor position, which, even on a standard E39, is not optimal.

Regards,

Rudi

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post #7 of 9 Old 15th March 2006, 10:02 AM Thread Starter
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@imolaman: I quite understand what you're saying, these are valid points. But I don't think this is what's happening right now, because it's winter now...
I'll have it checked next time the car goes in for service, or when I can get under the car myself, whichever comes first.
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post #8 of 9 Old 15th March 2006, 02:55 PM
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Quote:
Originally Posted by Frits
@imolaman: I quite understand what you're saying, these are valid points. But I don't think this is what's happening right now, because it's winter now...
I'll have it checked next time the car goes in for service, or when I can get under the car myself, whichever comes first.
Good luck with the situation. Please keep us posted of the outcome.

Regards, Rudi

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post #9 of 9 Old 23rd May 2006, 01:10 PM Thread Starter
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Ok, it took a while, but here is the update finally. 2 things were wrong... The sensor was not in the right place. I put the sensor in the hole where the wire came out, so I put it IN the bumper. The sensor should be located UNDER the bumper. This caused the measured temperature to be higher than normal. The second problem was that my sensor was damaged, from grinding over the concrete. I have a new sensor, located on the correct spot, and it works much much better now.

Last edited by Frits; 23rd May 2006 at 01:10 PM.
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