Temp gauge goes HOT- suggestions?

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vvurdsmyth
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Re: Temp gauge goes HOT- suggestions?

Postby vvurdsmyth » Wed Sep 05, 2012 4:48 am

As I figured, the electrical diagram (pg, 6210-2 of the '86 electronics manual) does not indicate which of the temp sensors it is, but it does show that the gauge gets its signal from the "service interval processor", which was disabled by a former owner.. but why should it frag' now...? hmm Anyone know which of the temp sensors is the one for the temp gauge..?
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Re: Temp gauge goes HOT- suggestions?

Postby Yoshi » Wed Sep 05, 2012 11:06 am

Unplug while running, see what each one does. The one that changes how the car runs is not the right one.
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Re: Temp gauge goes HOT- suggestions?

Postby vvurdsmyth » Wed Sep 05, 2012 2:09 pm

Brilliant suggestion Yohsi, maybe I'll get to it today; hopefully there is not another one that has no immediate affect on how it runs...; also it is a relief that gauge signal does not go through the computer.. explains why it runs well...; will let you know how the test turns out. Addendum: someone on another site suggested it is the single lead sensor on the thermo' housing.. sounds logical.. too bad I do't have a test unit; the way, I guess is to see if there is any current, likely a few milli-amps, from that sensor; hmm gotta pick up a cheepo test unit...
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Re: Temp gauge goes HOT- suggestions?

Postby ss45466 » Thu Sep 06, 2012 1:10 pm

The temp sensor for the gauge is tan, with a 2 prong housing but only 1 terminal. It should be one of the ones on top next to the fuel rail. One will be blue for the ecu and the other will be tan. This is how the late model e30's are, should be nearly the same for an early model. The sensors on the radiator are for the aux fan iirc.

Also you might want to check your grounds.
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Re: Temp gauge goes HOT- suggestions?

Postby vvurdsmyth » Thu Sep 06, 2012 3:11 pm

Thank you ss45466; you confirm what someone else mentioned, and I'm on top of it; early yesterday the temp suddenly was working... later it was not, the gauge showing hot; all of the temp connections have been cleaned with contact cleaner... the on and off of the temp gauge suggests a connection problem; I'm going back at it again today to see if that connection can be tightened up somehow...
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Re: Temp gauge goes HOT- suggestions?

Postby Yoshi » Thu Sep 06, 2012 3:12 pm

buy aftermarket gauge/probe. problem solved :)
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Re: Temp gauge goes HOT- suggestions?

Postby AustinR » Fri Sep 07, 2012 12:32 am

Yoshi wrote:buy aftermarket gauge/probe. problem solved :)


I have a feeling my interior is gonna be filled with aftermarket gauges as my car's stock wiring slowly fails. haha.

OP, let us know when you find the final solution!
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Re: Temp gauge goes HOT- suggestions?

Postby vvurdsmyth » Sat Sep 08, 2012 12:20 am

Problem Solved - thank you all; identifying the location of the culprit sensor was the key; the connection to the sensor was too lose.. I finally took a needle nose pliers and put a slight twist in the contact blade - that insures contact and everything is just 'ducky', as they say... Thanks again all..
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Re: Temp gauge goes HOT- suggestions?

Postby Yoshi » Sat Sep 08, 2012 1:16 am

W00t!
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Re: Temp gauge goes HOT- suggestions?

Postby vvurdsmyth » Sat Sep 08, 2012 1:41 am

Yes Yoshi, that is all it was... the blade/receptacle thing had apparently gotten too lose; hitting it with electric contact cleaner didn't help; it worked for one day, then went wonky again, clearly indicating a connection problem; an ever so slight twist in the the blade did the trick (~:
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Re: Temp gauge goes HOT- suggestions?

Postby Yoshi » Sat Sep 08, 2012 1:49 am

maybe replace a section of the wires. dielectric grease is your friend.
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Re: Temp gauge goes HOT- suggestions?

Postby vvurdsmyth » Sat Sep 08, 2012 2:25 am

Yoshi, I was hoping it wasn't a wire and I use electric contact cleaner on contacts; I'm going to put a slight twist in all those kind of connections that seem lose, or could be lose; who knows if some are not sending their signal the the CPU-

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