Temperature Gauge Success
09-05-2010, 09:42 PM
#81
Race Director
Thread Starter
07-08-2011, 01:33 PM
#82
Racer
Recently my temperature gauge started to read a little low (100-150 instead of 185) so I decided to swap out the sender with a unit from zip with no real troubleshooting. Needless to say that didn't solve the problem. I came across this thread and started some real troubleshooting. (I did check the temperatures with an IR heat gun and they are right where their supposed to be)
After pulling the center cluster out I was surprised to see my temperature gauge doesn't have the 90 ohm wire round resistor that everyone else seems to have so my potentiometer dialer-inner became pretty much useless sadly. (It has a thin piece of non conductive plastic in its place)
Next I made the 79 ohm tester and hooked it up to the sender unit connection and the guage read 210 like it was supposed to. Do some aftermarket gauges have the 90 ohm resistor built into it?
Next up for me to test is the sender unit itself once the car cools down, but it troubles me that I'm going to have to find a decent one of those instead of just being able to "dial in" the gauge with the potentiometer. Anyone else run into this before?
Also of note, I measured the resitance of the green wire from the sender to the guage and it was 4 Ohms... this seems off to me...
Thanks for the help.
After pulling the center cluster out I was surprised to see my temperature gauge doesn't have the 90 ohm wire round resistor that everyone else seems to have so my potentiometer dialer-inner became pretty much useless sadly. (It has a thin piece of non conductive plastic in its place)
Next I made the 79 ohm tester and hooked it up to the sender unit connection and the guage read 210 like it was supposed to. Do some aftermarket gauges have the 90 ohm resistor built into it?
Next up for me to test is the sender unit itself once the car cools down, but it troubles me that I'm going to have to find a decent one of those instead of just being able to "dial in" the gauge with the potentiometer. Anyone else run into this before?
Also of note, I measured the resitance of the green wire from the sender to the guage and it was 4 Ohms... this seems off to me...
Thanks for the help.
07-08-2011, 03:52 PM
#83
Race Director
Thread Starter
Some aftermarket gauges don't need the 90 ohm resistor.
79 ohms = 210 test....thats a good sign that your gauge is pretty close
Touch the 2 probes of your meter together and see if your meter reads 4 ohms,if so you need to zero it.(otherwise your test was 79+4)
For $6 you can try a BWD WT203 from Advanced Auto,bring it home and put it boiling water and if you get a reading 81 or 82 ohms put it in your car and see how your gauge reads. If you don't get a reading of 81-82 take it back and see if they will let you test another one.
79 ohms = 210 test....thats a good sign that your gauge is pretty close
Touch the 2 probes of your meter together and see if your meter reads 4 ohms,if so you need to zero it.(otherwise your test was 79+4)
For $6 you can try a BWD WT203 from Advanced Auto,bring it home and put it boiling water and if you get a reading 81 or 82 ohms put it in your car and see how your gauge reads. If you don't get a reading of 81-82 take it back and see if they will let you test another one.
07-09-2011, 01:49 AM
#84
Racer
Thanks Roger, I really appreciate your help and all the legwork you've done as well. It's kinda fun trying to dial this thing in. At least I'm slowly remembering a few things from my intro to EE course 5 years ago lol.
I boiled the sender I recieved from ZIP, it came in around 147 ohms. So I'm guessing it was an 80-82 sender that was just misboxed... oh well. I may give them a call and see what they can do.
I did pick up a WT203 from Advanced that came in at 83 Ohms. Hopefully that should work out well.
I boiled the sender I recieved from ZIP, it came in around 147 ohms. So I'm guessing it was an 80-82 sender that was just misboxed... oh well. I may give them a call and see what they can do.
I did pick up a WT203 from Advanced that came in at 83 Ohms. Hopefully that should work out well.
03-27-2016, 04:36 PM
#85
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Pretty sure I've got it now.
Theses crappy senders are enough to drive a guy nuts. I'm working on a 70 that is going for it's PV test and the temp gauge has never gone above the mark in-between the 100 and 210 mark.
I have tested senders from Lectric Limited , Paragon , Autozone , O Rileys and Advanced Auto.
I used boiling water , 212 degrees as a base for testing the senders (the gauge is marked at 210 so that is almost perfect). Most stock C3 gauges when inputted with 79-82 Ohms will read right around 212. So if you put a sender in boiling water it needs to have an ohms reading of 79-82 ohms to make the gauge read 212.
The best and closest senders I've found are the ones from Advanced and O-Rileys both from BWD #WT203 at $6 each. O-Rileys has an AC Delco also but it is exactly the same part as the WT203 but in an AC Delco box and has a price tag of $22. These all tested from 80-82 ohms in boiling water.
The Lectric Limited #06400759 and Autozone TU5 looked identical and tested identical , 102 ohms in boiling water.
102 ohms gives a gauge reading of aprox. 150 degrees ( no wonder so many think these senders are great , their engines appear to be running nice and cool). This is 62 degrees too cold , not good in my opinion.
Paragons #8454 looks different with the correct writing on it but it tested exactly the same as the LL and Autozone TU5 , 102 ohms in boiling water.
The LL and Paragon senders do have the correct pin for connecting the green sender wire.
On the BWD WT203 the connection is the thumb tack style.( For the 70 I am working on I ground the connector round to use the original harness connector.)
On the 70 the BWD WT203 was pretty close but because of the PV test I wanted to experiment and get a little closer. Here are some pics of the process using the WT203 sender and with the gauge resistor removed and a variable potentiometer set at 80 ohms (original resistor read 86 ohms).
This first pic is engine idling with a temp gun reading on top of thermostat housing of 198 and a reading of 201 at the base of the housing. I think its pretty close. Yahoo !
This pic is with a gun reading of 223 top and 226 base. So far so good.
I wanted to force the engine to run hotter but was difficult to do with the usual covering of the radiator. I had to all but pinch off the upper rad hose. Found out later in the process the TCS wasn't working correctly and at normal temps was allowing vacuum to reach the dist.
This last pic is with the engine off and the heat rising. I was hoping to see this so I was assured the sender would produce a high temp reading. The gun read 245 at this point and after a min or so read 260 and the gauge was buried into the red. I'm pretty satisfied for the purpose of protection this combination of sender,gauge and resistor is pretty accurate and will throw red flags when the engine is getting hot.
Here are couple more threads with some more temp gauge info.
http://forums.corvetteforum.com/c3-t...uge-stuff.html
http://forums.corvetteforum.com/c3-t...ender-pic.html
http://forums.corvetteforum.com/c3-g...-ohms-law.html
Theses crappy senders are enough to drive a guy nuts. I'm working on a 70 that is going for it's PV test and the temp gauge has never gone above the mark in-between the 100 and 210 mark.
I have tested senders from Lectric Limited , Paragon , Autozone , O Rileys and Advanced Auto.
I used boiling water , 212 degrees as a base for testing the senders (the gauge is marked at 210 so that is almost perfect). Most stock C3 gauges when inputted with 79-82 Ohms will read right around 212. So if you put a sender in boiling water it needs to have an ohms reading of 79-82 ohms to make the gauge read 212.
The best and closest senders I've found are the ones from Advanced and O-Rileys both from BWD #WT203 at $6 each. O-Rileys has an AC Delco also but it is exactly the same part as the WT203 but in an AC Delco box and has a price tag of $22. These all tested from 80-82 ohms in boiling water.
The Lectric Limited #06400759 and Autozone TU5 looked identical and tested identical , 102 ohms in boiling water.
102 ohms gives a gauge reading of aprox. 150 degrees ( no wonder so many think these senders are great , their engines appear to be running nice and cool). This is 62 degrees too cold , not good in my opinion.
Paragons #8454 looks different with the correct writing on it but it tested exactly the same as the LL and Autozone TU5 , 102 ohms in boiling water.
The LL and Paragon senders do have the correct pin for connecting the green sender wire.
On the BWD WT203 the connection is the thumb tack style.( For the 70 I am working on I ground the connector round to use the original harness connector.)
On the 70 the BWD WT203 was pretty close but because of the PV test I wanted to experiment and get a little closer. Here are some pics of the process using the WT203 sender and with the gauge resistor removed and a variable potentiometer set at 80 ohms (original resistor read 86 ohms).
This first pic is engine idling with a temp gun reading on top of thermostat housing of 198 and a reading of 201 at the base of the housing. I think its pretty close. Yahoo !
This pic is with a gun reading of 223 top and 226 base. So far so good.
I wanted to force the engine to run hotter but was difficult to do with the usual covering of the radiator. I had to all but pinch off the upper rad hose. Found out later in the process the TCS wasn't working correctly and at normal temps was allowing vacuum to reach the dist.
This last pic is with the engine off and the heat rising. I was hoping to see this so I was assured the sender would produce a high temp reading. The gun read 245 at this point and after a min or so read 260 and the gauge was buried into the red. I'm pretty satisfied for the purpose of protection this combination of sender,gauge and resistor is pretty accurate and will throw red flags when the engine is getting hot.
Here are couple more threads with some more temp gauge info.
http://forums.corvetteforum.com/c3-t...uge-stuff.html
http://forums.corvetteforum.com/c3-t...ender-pic.html
http://forums.corvetteforum.com/c3-g...-ohms-law.html
03-27-2016, 04:49 PM
#87
Team Owner
Member Since: Sep 2006
Location: Westminster Maryland
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Hi,
Me TOO!!!!
I checked and it still appears he's been away since 2012.
Sure could use his 'voice of reason' and 'KNOWLEDGE' quite often.
Regards,
Alan
Me TOO!!!!
I checked and it still appears he's been away since 2012.
Sure could use his 'voice of reason' and 'KNOWLEDGE' quite often.
Regards,
Alan
03-27-2016, 11:44 PM
#88
Former Vendor
Member Since: Aug 2006
Location: Jeffersonville Indiana 812-288-7103
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
I still talk to Roger a couple of times a year.... he's living the high life in Fl retired. He doesn't have internet service where he lives so it's complicated.
As for the Evern Erdogan.. Keep the sender you have and install the appropriate adjustable resistor in your gauge.
175 ohms is no where near where that sender needs to be and the one you have is probably closer to that. With this resistor you can induce a linear change into the non linear gauge.
https://willcoxcorvette.com/catalogs...table+Resistor
-Willcox
As for the Evern Erdogan.. Keep the sender you have and install the appropriate adjustable resistor in your gauge.
175 ohms is no where near where that sender needs to be and the one you have is probably closer to that. With this resistor you can induce a linear change into the non linear gauge. https://willcoxcorvette.com/catalogs...table+Resistor
-Willcox
03-28-2016, 12:02 AM
#89
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[QUOTE=Willcox Corvette;1591869834]I still talk to Roger a couple of times a year.... he's living the high life in Fl retired. He doesn't have internet service where he lives so it's complicated.
As for the Evern Erdogan.. Keep the sender you have and install the appropriate adjustable resistor in your gauge. 175 ohms is no where near where that sender needs to be and the one you have is probably closer to that. With this resistor you can induce a linear change into the non linear gauge.
https://willcoxcorvette.com/catalogs...table+Resistor
-Willcox[/QUO
My sender had no ohms .I tried to put the new one in the one with high ohms .guess what it was too small I took the old one out it was earlier model size so I bought one for 71 Corvette .and boiling water test came out good with 82 ohms I put it in.I guess they made a new thread before me when they rebuild the engine it's original block .so it looks okay for now .thanks Willcox
As for the Evern Erdogan.. Keep the sender you have and install the appropriate adjustable resistor in your gauge.
175 ohms is no where near where that sender needs to be and the one you have is probably closer to that. With this resistor you can induce a linear change into the non linear gauge. https://willcoxcorvette.com/catalogs...table+Resistor
-Willcox[/QUO
My sender had no ohms .I tried to put the new one in the one with high ohms .guess what it was too small I took the old one out it was earlier model size so I bought one for 71 Corvette .and boiling water test came out good with 82 ohms I put it in.I guess they made a new thread before me when they rebuild the engine it's original block .so it looks okay for now .thanks Willcox
