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Discussion Starter #1
Hi all,

Having some issue with my temp gauge sender. Whats happening is when i turn the car on, the temp gauge goes from cold to past hot in a matter of minutes. I def know the engine isnt that hot as i have hooked up a mechanical temp gauge and car is getting to temp fine and staying there. Just the gauge is going off the chart!

I have a 67 with all new wiring, new gauges, new temp sender (the one to match the gauges) you name it i have replaced it. I have the sender in the intake as i have alloy heads and there is no hole for the sender in the head (have been told this will not alter the temp that much, not like it is climbing anyways).

Is it possible for the sender to be faulty? or is there something i am missing? I have had the autoelec check it out and he says the wiring is perfect must be the sender. i have replaced the sender with different senders (from different V8 engine out here in AUS) and they all do the same thing some a little slower than others but still climb and climb with only car idling for a minute or 2 max.

Should i order another temp sender for the gauges for the car agin and see if it does anything?

What am i missing here? its been doing my head in for a few weeks now!

Cheers,

Dan.
 

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Take the sending unit and suspend it in a pan of water on the stove and boil the water.
Use a thermometer if you like, but water boils at sea level at 212°F (100°C).
When water boils for one minute, remove the sending unit and measure the resistance between the body and its terminal, should be somewhere around 100-150 ohms.
Now knowing what resistance is needed for 210°F, acquire a 0-500 ohm or 0-1000 ohm potentimeter and adjust for the same resistance. Now hook up the pot to the dark green wire for the gauge and ground and see what happens.

If gauge continues to max out, need a new gauge. The less resistance, the higher the gauge reading.
 

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Discussion Starter #3
Will try what you say when i get home tonight, what happens if its not the gauges? i cant see it be as they are brand new. I have also had the autoelec hook up a OHMs? reader and the needle moves as its told.

Much appreciated.
 

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Putting an ohmmeter across the gauge terminals and the needle pegs, is a good sign.

What might need to be done as an experiment, hook your potentiometer at the 210°F resistance between a 5 volt power supply, three 'D' cell batteries in series would work, a gauge post and the other gauge terminal back to the batteries and see what the gauge displays. If the needle goes in the opposite direction, reverse the gauge hookup.

Some gauges work on a 5 volt power supply and need a resistor to send 5 volts through the gauge to the sending unit, 12-14 volts is too much. Gauges work on current, not voltage, but lower voltage gives less current. So you might be missing a voltage dropping resistor for the gauge.
 

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The odds are you have the wrong sender spec...And as Aussie and NZ are similar in our car fleets, our Holden ford jappa senders off the shelf are all different to the US 1st gen Camaro... althu some are closer than others.
A good auto sparky can add a resistor in the circuit to get it close..the trouble is most sparkies today are just R&R and have no idea of the parameters Everett is talking about above.
 

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Discussion Starter #6
The original Temp sender is the "correct" sender (have checked part number) for the gauges which i got from the US as with the gauges, wire looms etc so in theory the temp sender is "correct". The gauges are new OEM/OER from Matts classic bowties which are meant to be correct for 1st gen camaros (in my case the 67 console gauges) also.

I have only tried other senders as the autoelec measured the range of ohms of the gauges so i tried to find one that matched. Only the same thing happens the needle pegs past hot after 1-2 minutes of idle.

Everett i will check/suss out the volts that you think could be an issue, might be too much going to the gauges.

I wouldnt think this would be so difficult!

Thanks guys.
 

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Discussion Starter #7
Hi Guys,

I was looking through my AIM and noticed the gauges are meant to be grounded. I have a ground on there for the clock but not sure for temp etc. Could this be the problem? a bad ground?

Many thanks.
 
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