Temp gauge adjustable resistor question
Thread Starter
Le Mans Master
Joined: Jan 2001
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Temp gauge adjustable resistor question
So, I got my adjustable resistor from Willcox and installed it per the video below. It all seemed to go together well but I do NOT get the response shown on the video when I rotate the screw.... of course there are some notes on the video about having ohms present??
My temp gauge needle does NOT move when I tweak the adjustable resistor.
I am a bit confused. Should the temp gauge needle move with just the adjustable resistor installed? Or do i need to hook up the unit to the vehicle temp sender and power up the system?
http://repairs.willcoxcorvette.com/w...deo-1968-1976/
My temp gauge needle does NOT move when I tweak the adjustable resistor.
I am a bit confused. Should the temp gauge needle move with just the adjustable resistor installed? Or do i need to hook up the unit to the vehicle temp sender and power up the system?
http://repairs.willcoxcorvette.com/w...deo-1968-1976/
Melting Slicks
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From: Canberra Australia
2025 C3 of the Year Finalist - Modified
For the variable resistor to adjust the reading on the temp gauge you will need to complete the circuit to ground via the temperature sender etc
Thread Starter
Le Mans Master
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Thanks - I'll check after I reassemble...
That makes me feel a bit better. I guess I'll check it when I put it all back together.
I did check the variable resistor and it does vary so that's good. I placed it at 90 ohms for now.
Also checked my REALLY old stock resistor..... it read 86.3 ohms... pretty amazing considering it's so old.
Thanks CraigH
I did check the variable resistor and it does vary so that's good. I placed it at 90 ohms for now.
Also checked my REALLY old stock resistor..... it read 86.3 ohms... pretty amazing considering it's so old.
Thanks CraigH
Former Vendor
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From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
That makes me feel a bit better. I guess I'll check it when I put it all back together.
I did check the variable resistor and it does vary so that's good. I placed it at 90 ohms for now.
Also checked my REALLY old stock resistor..... it read 86.3 ohms... pretty amazing considering it's so old.
Thanks CraigH
I did check the variable resistor and it does vary so that's good. I placed it at 90 ohms for now.
Also checked my REALLY old stock resistor..... it read 86.3 ohms... pretty amazing considering it's so old.
Thanks CraigH
Willcox
Thread Starter
Le Mans Master
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Thanks... I'll check it ...
It's easy enough to hook it up temporarily since I have everything torn apart.
90 ohms is the best starting point.. but as Craig stated, you must also have input ohms for the gauge to function. You can test the gauge before you install it in the car by applying power and ground to it (the gauge should peg cold) and then ground out the ohms input stud to the ground stud and you should get a hot temperature. If it's working in this manner everything is good, it's it's not then post back.
Willcox
Willcox
Former Vendor
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From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Yeah.. just find an old flasher if you want a ohms input, they run around 50-55 ohms on average. Don't try to adjust anything though... but if you want to see a change you could stagger two in series, test the ohms and use that for a 100 - 110 imput..
I say don't set anything because you want to balance your temperature sender to the dash unit by using a verified result. Meaning if you know what thermostat you have in the car and it opens at 180, then hold your hand on the hose and when you feel the water get hot, dial the gauge to 180... or use an IR gun.. either way will get you close.
Willcox
I say don't set anything because you want to balance your temperature sender to the dash unit by using a verified result. Meaning if you know what thermostat you have in the car and it opens at 180, then hold your hand on the hose and when you feel the water get hot, dial the gauge to 180... or use an IR gun.. either way will get you close.
Willcox
Thread Starter
Le Mans Master
Joined: Jan 2001
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I have ez-efi 2.0 digital temp indication
SO.... when I get around to adjusting gauge - it should be easy (assuming the gauge works
.
I should be able to hook it up easily to the regular connector before I put everything back together.
I'm guessing that intermediate mark is about 155 degrees?
. I should be able to hook it up easily to the regular connector before I put everything back together.
I'm guessing that intermediate mark is about 155 degrees?
Yeah.. just find an old flasher if you want a ohms input, they run around 50-55 ohms on average. Don't try to adjust anything though... but if you want to see a change you could stagger two in series, test the ohms and use that for a 100 - 110 imput..
I say don't set anything because you want to balance your temperature sender to the dash unit by using a verified result. Meaning if you know what thermostat you have in the car and it opens at 180, then hold your hand on the hose and when you feel the water get hot, dial the gauge to 180... or use an IR gun.. either way will get you close.
Willcox
I say don't set anything because you want to balance your temperature sender to the dash unit by using a verified result. Meaning if you know what thermostat you have in the car and it opens at 180, then hold your hand on the hose and when you feel the water get hot, dial the gauge to 180... or use an IR gun.. either way will get you close.
Willcox
Former Vendor
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From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
I believe the first mark was actually closer to 180 than 155.
I don't know what the actual temperature should be, but below you can see from the factory expected inputs what the ohms should be at what mark. This will not help you though since the issue you are trying to correct is the input ohms (from the sender) and not the expected ohms.
I'd just play around with it and get say, 180 somewhere you are comfortable with. Possibly make the 180 temperature the first mark and when you are set... then run the engine again and check the first mark at 100 degrees.
The gauge is non linear so the change in input ohms to make a change to the gauge drastically increases as car gets warmer. The resistor will not make a linear change to the non-linear gauge but the scale will still stay the same. (I hope that makes sense)...
Willcox
I don't know what the actual temperature should be, but below you can see from the factory expected inputs what the ohms should be at what mark. This will not help you though since the issue you are trying to correct is the input ohms (from the sender) and not the expected ohms.
I'd just play around with it and get say, 180 somewhere you are comfortable with. Possibly make the 180 temperature the first mark and when you are set... then run the engine again and check the first mark at 100 degrees.
The gauge is non linear so the change in input ohms to make a change to the gauge drastically increases as car gets warmer. The resistor will not make a linear change to the non-linear gauge but the scale will still stay the same. (I hope that makes sense)...
Willcox
Last edited by Willcox Corvette; Dec 15, 2016 at 03:03 PM.
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Thread Starter
Le Mans Master
Joined: Jan 2001
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Thanks, I'll check it against my digital readout when installed
Hmmm... I'll cross-check it against the digital readout from my ez-efi 2.0 once I get around to putting it together.
I plotted a quick manual graph of ohms vs gauge readout and it does appear that the middle mark (between 100 and 210) should be about 180 degrees.
Thanks.
I plotted a quick manual graph of ohms vs gauge readout and it does appear that the middle mark (between 100 and 210) should be about 180 degrees.
Thanks.
I believe the first mark was actually closer to 180 than 155.
I don't know what the actual temperature should be, but below you can see from the factory expected inputs what the ohms should be at what mark. This will not help you though since the issue you are trying to correct is the input ohms (from the sender) and not the expected ohms.
I'd just play around with it and get say, 180 somewhere you are comfortable with. Possibly make the 180 temperature the first mark and when you are set... then run the engine again and check the first mark at 100 degrees.
The gauge is non linear so the change in input ohms to make a change to the gauge drastically increases as car gets warmer. The resistor will not make a linear change to the non-linear gauge but the scale will still stay the same. (I hope that makes sense)...
Willcox
I don't know what the actual temperature should be, but below you can see from the factory expected inputs what the ohms should be at what mark. This will not help you though since the issue you are trying to correct is the input ohms (from the sender) and not the expected ohms.
I'd just play around with it and get say, 180 somewhere you are comfortable with. Possibly make the 180 temperature the first mark and when you are set... then run the engine again and check the first mark at 100 degrees.
The gauge is non linear so the change in input ohms to make a change to the gauge drastically increases as car gets warmer. The resistor will not make a linear change to the non-linear gauge but the scale will still stay the same. (I hope that makes sense)...
Willcox
Former Vendor
Joined: Aug 2006
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From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
In most instances, that first mark is 180. (aprox). This gauge is not one of the most accurate gauges to say the least. 
Willcox
Willcox
Thread Starter
Le Mans Master
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This is one nifty contraption :)
Well, I finally got around to installing this adjustable resistor. Set the EZ-EFI to start the fan at 180 degrees, started the car, drove around a bit and let her warm up....
I watched the digital temperature indication on the EZ-EFI controller as it went through 180 degrees. I tweaked the resistor so the gauge indicated 180(well, what we think is about 180) at the same time that the digital indicator read 180. It was reading a bit low --- I was surprised how many turns it required, but no biggie - reads great!
It's just wonderful. Thanks Willcox.
I watched the digital temperature indication on the EZ-EFI controller as it went through 180 degrees. I tweaked the resistor so the gauge indicated 180(well, what we think is about 180) at the same time that the digital indicator read 180. It was reading a bit low --- I was surprised how many turns it required, but no biggie - reads great!
It's just wonderful. Thanks Willcox.
Last edited by carriljc; Jan 29, 2017 at 09:16 PM.
Thread Starter
Le Mans Master
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...and a little oddity pending warmup..
UPDATE: The Temp Gauge was reading about 5 o'clock because the connector behind was not snug and tight. I wiggled it and the temp went right back to the bottom of scale this morning. Next time I pull the center dash panel out I will clean the connectors and make sure it's nice and tight.
This adjustable resistor is quite fantastic. I was able to monitor the temperature rise from 100 to the approximate 180 degree mark (halfway between 100 and 210) and it tracks quite nicely.
*********************
NOTE: BELOW IS ORIGINAL COMMENT --- IT WAS CORRECTED AS STATED ABOVE....LEFT IT HERE FOR REFERENCE PURPOSES:
So, I take the car out for a short drive to see how things are working. I notice that the temperature gauge is at about 5 o'clock ...hmmmm....guess I'll pull over in a little bit to see if something came loose.
So I drive along for the next opportunity to pull over..... next time I look, and the car is now warmed up, the temperature reads just fine.
Curiouser and curiouser. Seemed to work fine after that.
I'll check again tomorrow when cold.
This adjustable resistor is quite fantastic. I was able to monitor the temperature rise from 100 to the approximate 180 degree mark (halfway between 100 and 210) and it tracks quite nicely. *********************
NOTE: BELOW IS ORIGINAL COMMENT --- IT WAS CORRECTED AS STATED ABOVE....LEFT IT HERE FOR REFERENCE PURPOSES:
So, I take the car out for a short drive to see how things are working. I notice that the temperature gauge is at about 5 o'clock ...hmmmm....guess I'll pull over in a little bit to see if something came loose.
So I drive along for the next opportunity to pull over..... next time I look, and the car is now warmed up, the temperature reads just fine.
Curiouser and curiouser. Seemed to work fine after that.
I'll check again tomorrow when cold.
Last edited by carriljc; Feb 2, 2017 at 08:46 AM. Reason: Added note to avoid confusion--
Team Owner
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Recheck your coolant level. Sometimes you can get an air pocket in the system when it is being filled. After running, the air goes out and the coolant level could be low.
Last edited by 7T1vette; Feb 1, 2017 at 11:59 AM.
Former Vendor
Joined: Aug 2006
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From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
I have about 1 year of research in this thing so I'm glad it's working out... Now if I could just figure out what other gauges this thing will work with I'd be all set.. (camaro, chevelle, nova, etc....) Willcox
Thread Starter
Le Mans Master
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I will test to 210 degrees when I get car back together....
Since it seemed to track quite nicely between 100 and 180(allegedly)- my next experiment will be to check how tracks between 180 and 210.
I plan to delay fan start until 210 degrees and see how the gauge tracks.
AND TEMP SENDER EXPERIMENT:
I also have a Temp Sender Duralast TU66 installed in the 3/8" hole for the Vortec heads. It read about the same as the large original sender (large original sender now installed in the intake manifold) when I installed it in the 3/8" hole for the Vortec heads.
(see here:
https://www.corvetteforum.com/forums...post1581659826 )
I will also swap the sensor lead over to the 3/8" TU66 and see how it tracks. IF IT TRACKS about the same as the original, then I think we'll have a good alternate for 3/8" holes in newer heads..... gotta put the dash back together first though.
I plan to delay fan start until 210 degrees and see how the gauge tracks.
AND TEMP SENDER EXPERIMENT:
I also have a Temp Sender Duralast TU66 installed in the 3/8" hole for the Vortec heads. It read about the same as the large original sender (large original sender now installed in the intake manifold) when I installed it in the 3/8" hole for the Vortec heads.
(see here:
https://www.corvetteforum.com/forums...post1581659826 )
I will also swap the sensor lead over to the 3/8" TU66 and see how it tracks. IF IT TRACKS about the same as the original, then I think we'll have a good alternate for 3/8" holes in newer heads..... gotta put the dash back together first though.
Last edited by carriljc; Feb 2, 2017 at 09:00 AM. Reason: add sender check comment
Thread Starter
Le Mans Master
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Posts: 6,741
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Duralast TU66 Temp Sender installed in the 3/8" hole for the Vortec head and gauge adjustment testing with Willcox Adjustable resistor.
The original 1/2" sensor on the passenger side intake, next to the thermostat, has been working wonderfully for years.
I am finally getting around to testing the TU66 temp sender that I installed on the driver side head ages ago.
Attached are some photos of the testing sequence I went through today.
Tomorrow (well, hopefully tomorrow) I will adjust my fan start & stop temps to the 212 range and see how the sensor responds above my Normal Operating Temp(NOT) of 175°F-180°F.
Anyway, I'll post the pictures one at a time so that I don't get them out of sequence.
The original 1/2" sensor on the passenger side intake, next to the thermostat, has been working wonderfully for years.
I am finally getting around to testing the TU66 temp sender that I installed on the driver side head ages ago.
Attached are some photos of the testing sequence I went through today.
Tomorrow (well, hopefully tomorrow) I will adjust my fan start & stop temps to the 212 range and see how the sensor responds above my Normal Operating Temp(NOT) of 175°F-180°F.
Anyway, I'll post the pictures one at a time so that I don't get them out of sequence.
