bad sending unit?...water temp
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
bad sending unit?...water temp
so i tested the wire from the sending unit and was around 11v...i checked the back of the gauge and was around 11-12v.... but the water temp gauge doesnt move.....i believe the gauge is new and the circuit board seems fine.... could it be a shyt sending unit???....
Le Mans Master
Joined: Jan 2007
Posts: 5,485
Likes: 7
From: Peekskill NY
Are you not getting a fuel level reading on your gauge? Mine use to swing all over the place, then it leaked, so replaced it, and now the gauge is fairly steady.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Try the standard test. Key to ON
Remove the sender wire from sender and the gauge should read cold
Ground the sender wire to the engine and the gauge should read hot.
Let us know what happens.
Willcox site has some tests also.
Remove the sender wire from sender and the gauge should read cold
Ground the sender wire to the engine and the gauge should read hot.
Let us know what happens.
Willcox site has some tests also.
Melting Slicks
Joined: Feb 2001
Posts: 2,608
Likes: 3
From: TEXAS - you mean there are other states?
So.... Rog - I just did your test and the meter pegged wayyyyy past 250 (about 3 o'clock). So my gauge must be good. The sending unit is brand new from Lectric Limited. I do have a very small amount of teflon tape at the last threads on the sending unit. I pulled that and re-inserted (dangit - coolant everywhere
). All looks good.But - I do see where my Lectric Limited harness connector to the sending unit was quite loose.... so - I pulled the connector and closed it a bit. Now it fits snug. Will see what happens when I crank it next time.
Burning Brakes
Joined: Nov 2006
Posts: 893
Likes: 7
From: Orange Park Florida
Kaiserbud,
Would you perform a gauge test for me? With the ignition off, pull off the temp sender wire and connect one lead from the meter to it. Then connect the other meter lead to a solid ground (the manifold will do). Using the ohms scale let me know what the reading is. For early C3s I believe it should be in the 200-220 ohm range. I'm trying to find out if this measurement will give us a baseline for determining temp meter accuracy without having to remove the dash for access to the rear of the meter.
Thanks in advance!
Would you perform a gauge test for me? With the ignition off, pull off the temp sender wire and connect one lead from the meter to it. Then connect the other meter lead to a solid ground (the manifold will do). Using the ohms scale let me know what the reading is. For early C3s I believe it should be in the 200-220 ohm range. I'm trying to find out if this measurement will give us a baseline for determining temp meter accuracy without having to remove the dash for access to the rear of the meter.
Thanks in advance!
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
I am not getting a reading on my temp gauge. Now I may have not let it run long enough to heat up as this is a complete restoration and I am verifying EVERYTHING.
So.... Rog - I just did your test and the meter pegged wayyyyy past 250 (about 3 o'clock). So my gauge must be good. The sending unit is brand new from Lectric Limited. I do have a very small amount of teflon tape at the last threads on the sending unit. I pulled that and re-inserted (dangit - coolant everywhere). All looks good.
But - I do see where my Lectric Limited harness connector to the sending unit was quite loose.... so - I pulled the connector and closed it a bit. Now it fits snug. Will see what happens when I crank it next time.
So.... Rog - I just did your test and the meter pegged wayyyyy past 250 (about 3 o'clock). So my gauge must be good. The sending unit is brand new from Lectric Limited. I do have a very small amount of teflon tape at the last threads on the sending unit. I pulled that and re-inserted (dangit - coolant everywhere
). All looks good.But - I do see where my Lectric Limited harness connector to the sending unit was quite loose.... so - I pulled the connector and closed it a bit. Now it fits snug. Will see what happens when I crank it next time.
If it doesn't read 78-81 your gauge will be off.
If the reading in boiling water is 95-105 your gauge will read much colder than your engine actually is , probably around 150 degrees.
If you would like I can send you a small tester to plug into your green sender wire at the engine that should make your gauge read 210 degrees.Tester in pic.
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Melting Slicks
Joined: Feb 2001
Posts: 2,608
Likes: 3
From: TEXAS - you mean there are other states?
Hi guys.... just home from the days work...
Jim - I will address tomorrow.
Rog - thats sounds interesting - if I do not get resolved by the weekend - you bet. thanks
As for testing - I did not - I wanted to get the sending unit back in to stop the leak. I may indeed change my laziness if things do not progress in the right direction.
Jim - I will address tomorrow.
Rog - thats sounds interesting - if I do not get resolved by the weekend - you bet. thanks
As for testing - I did not - I wanted to get the sending unit back in to stop the leak. I may indeed change my laziness if things do not progress in the right direction.
Melting Slicks
Joined: Feb 2001
Posts: 2,608
Likes: 3
From: TEXAS - you mean there are other states?
Hi Jim - I did your test using a Radio Shack 22-218 which does not have digital readouts. I had to 'zero' it out and then obtained these readings:
No ignition on (in fact no battery). Mt Sending Unit is from Lectric Limited
200 ish Temp Sending Unit Tip to ground
0 Temp Sending Wire (from Gauge) to manifold ground
0 Temp Sending Gauge Base to manifold ground
Rog - By tightening the wire clamp onto the temp sending unit, I was able to get a temperature reading at the interior temp gauge.
I also let it run a bit longer (building up my courage [[or nerve]])
and FINALLY the DeWitts Spal Fans came on. The newness and oil are burning off and I am just very protective at this stage 
The gauge read 190-200ish so I assume the fans are set at 180. Will have to check DeWitts website.
No ignition on (in fact no battery). Mt Sending Unit is from Lectric Limited
200 ish Temp Sending Unit Tip to ground
0 Temp Sending Wire (from Gauge) to manifold ground
0 Temp Sending Gauge Base to manifold ground
Rog - By tightening the wire clamp onto the temp sending unit, I was able to get a temperature reading at the interior temp gauge.
I also let it run a bit longer (building up my courage [[or nerve]])
and FINALLY the DeWitts Spal Fans came on. The newness and oil are burning off and I am just very protective at this stage The gauge read 190-200ish so I assume the fans are set at 180. Will have to check DeWitts website.
