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I supported Toymods
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I renounced punctuation
Registered:
May 2002
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Temperature senders
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Sun, 20 March 2005 23:47
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Most temperature senders decrease in resistance with increasing temperature.
However, Toyota, in their infinite wisdom, chose to run a temperature sender that increases in resistance with increasing temperature in the 1960-67 Toyota Crowns.
Can anyone suggest where on earth I can find such a thing? The sender doesn't have to be Toyota, nor does it have to be internally voltage regulated (like the Toyota one is).
Please don't say another 1960-67 Crown as these are impossible to find - most have had engine cxhanges and the original sender went to the bin with the dead engine. Also don't suggest the local instrument gauge shop as they just want to sell me a very swish VDO temp gauge (which I don't have a problem with but I prefer to keep the original look of the car).
I have even tried to source one from Japan via the Crown Classics shop to no avail. Toyota Japan say the sender is discontinued (no surprise there).
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Temperature senders
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Mon, 21 March 2005 00:06
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thats nice of them!
do you know some values on the temp/resistance curve?
digikey has a few PTC thermistors.. made by these guys...
http://www.thermometrics.com/assets/images/ptcnote s.pdf
PTC's seem to have drastic resistance changes with temp compared to NTC's...
if i had half an idea about electronics, i'd suggest to use some sort of PIC to enable the use of a mre normal sensor....
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: Temperature senders
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Mon, 21 March 2005 00:51
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The resistance range appears to be about 30-50 ohms cold and about 300 hot. I have a day off tomorrow so I plan to map out a curve for the what the gauge sees.
I can externally regulate the gauge using a 7V regulator out of an old Holden.
At the moment the only way I know if the engine is over 90 degrees is by the thermo fans going off!
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Location:
Brisbane
Registered:
May 2002
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Re: Temperature senders
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Mon, 21 March 2005 01:00
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What are the chances of getting a gauge out of some other toyota (one that uses the normal temp sensor) and putting the guts of that into the back of the gauge? That way it would still look bog stock  Guess its a fair bit more work tho than just finding a temp sender to do the job!
Cheers
Wilbo
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Temperature senders
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Mon, 21 March 2005 01:02
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i was just abotu to suggest the same...
the VDO gauges are quite small inside and they often go on ebay for around $20-30.. would be pretty easy to adapt, but it means ripping bits out of your original dash...
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: Temperature senders
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Mon, 21 March 2005 01:11
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I'm gradually reaching that point where I'll just slap the motion of some gauge into my Crown dash and run the matched sender. It's a bit more work than I had planned but it's less work than replacing a cooked 1UZ.
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Location:
Brisbane
Registered:
February 2003
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Re: Temperature senders
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Mon, 21 March 2005 02:10
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GT - have a search thru the msefi forum as there are some euro cars that have the inverted behaviour of temp sensors as well.
i recall a thread that started with a euro car owner wanting to re-use the factory sensors for megasquirt.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: Temperature senders
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Mon, 21 March 2005 04:15
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usually most thermistors have a non-linear response curve - bastards.
Do a quick high-school style experiment and plot resistance vs temperature and then pick something which matches of course.
If you get stuck finding a part, send me the details and i will waste the time of one of my suppliers 
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