My Temp Gauge I Making Me Hot Under The Collar

[dodj]

When Redline redid your gauges, they were left stock, correct?

[dodj]

When I disconnect the wire, from the sender, the gauge does not move, at all. Mopar5 also suggested that I remove the wire, at the gauge and check for continuity. I will probably dig a little deeper, today, and do that. I think that I will need to remove the cluster, to do so.

With the evidence you have, you don't need to remove the cluster.

[Bullitt-]

   I imagine that Redline upgraded your voltage limiter to a solid state piece?
              If NOT I have a theory.......... poor ground to the limiter.

[Mopar5]

If you find you do have continuity on the wire to the sending unit . Most meters have a continuity buzzer built in you can set it on tone and then go through and wiggle the harness peice by peice and if you are lucky you may hear the meter go silent and then you are in the vicinity of the short to  ground. If you dont have a tone setting on your meter you can get a cheap 12 volt buzzer and put some leads on it and for safety I would put a 1 amp fuse on the hot side of the buzzer lead as close to the end of the wire as possible at the point of connection to power.. I like a buzzer better than using a light because you dont have to keep an eye on it. Its worth the time to make because you can use it for trouble shooting other stuff.

[floorit426]

First of all, Redline restored the gauges, did the ammeter conversion, and added an oil pressure gauge, to the clock location. As for the voltage limiter, I'm not sure.

Please bear with my ignorance, but I'm not sure what I'm looking for. Does the violet wire carry any voltage, with the key on? I am under the impression that it is a ground wire and the resistance of the sender is what determines the amount of voltage goes though the circuit.

[Jay Bee]

 [/quote]

I did check the resistance, of the old unit, and could not get a reading.

Was your meter on the right range scale? If it was set to the 200 ohms scale you wouldn't read anything.

Your sender should read about 80 or so ohms cold, 10 ohms or so hot.

Sorry, but I have to disagree. I think these resistance numbers only apply to the fuel sending unit. When I get a chance I'll remove mine from my car and measure it.

In the meantime here's some values from my spare temperature sending unit. It was replaced when the motor was rebuilt in 2011.
630 ohms - sandwiched between 2 ice cubes (no pic)
270 ohms - at room temperature (+or- 5 ohms)
44.9 ohms - in boiling water (+or- 5 ohms)

Too bad you don't have a, say, 75 ohm resistor you could temporarily substitute for the sending unit and see if your gauge still pegs. I can't wait to find out what this ends up being.

[floorit426]

I just put a volt meter on the wire sending unit side, of the wire. It registered 10.8 volts, with the key in the "on" position. Shouldn't it be in the 5 volt range?

[Jay Bee]

@floorit426 Well, that 10.8v is a problem. My car is a pulsating voltage (2.3 - 5.5v) with the key on "ON", "ACC" and with the motor running. Just like my regulator on the back of the cluster. What's weird is that if it's your 5v regulator then your fuel gauge would be pegging too. Didn't you say you don't have your fuel gauge grounded properly. If that's the case ground that properly and see it it pegs too.

Here's the resistance readings of the temp sender that's in my car.

231 ohms - room temperature
24.6 ohms - in boiling water (+ or- some)

[Bullitt-]

I just put a volt meter on the wire sending unit side, of the wire. It registered 10.8 volts, with the key in the "on" position. Shouldn't it be in the 5 volt range?

I just put a volt meter on the wire sending unit side, of the wire. It registered 10.8 volts, with the key in the "on" position. Shouldn't it be in the 5 volt range?

Kind of lines up with my thinking that IF you have the original mechanical voltage limiter with a poor ground the unit is not cycling as Jay Bee has stated his does..  I'ts taking the 5-seconds to heat up enough to open the contacts......
IF this is what's happening, why the fuel & oil gauges don't peg also is perplexing.....

[floorit426]

I will reground the fuel sender one more time and see what happens. Also, when I checked voltage, at the sender end, there was no pulse, either. It was a solid reading.

[Jay Bee]

As a sidebar, the first batch of solid state 5v regulators that were made by Greg Garner of Real Time Engineering actually pulsed like the old mechanical ones. It has 3 pins on the back allowing for the condenser. I have one of those in my car.

There are some reproductions, namely Vans, (probably others too) that are a steady 5v out. I bought one of those for a cluster I sold. Those only have 2 pins on the back, no need for the condenser/capacitor.

[Jay Bee]

@Bullitt-  He has a standard dash and Redline put an oil gauge in the clock spot, maybe they used a 12v gauge and that's why it doesn't peg    Apparently, Redline also replaced his regulator.

[floorit426]

I can't seem to find the work order. I will call them, Monday, and see if they have a record of what was done.

[dodj]

Sorry, but I have to disagree. I think these resistance numbers only apply to the fuel sending unit.

No need to be sorry Jay Bee, you are 100% correct 

I just put a volt meter on the wire sending unit side, of the wire. It registered 10.8 volts, with the key in the "on" position. Shouldn't it be in the 5 volt range?

Ya...or pulsing to 0 as bullit's theory is suggesting, but if that's the case, the fuel gauge should peg as well. You reported a fuel gauge issue, but it's not consistent with a high regulator output.  Oil pressure would peg as well, but being a new added piece, it may or may not be stock configuration.

  Apparently, Redline also replaced his regulator.

Also, when I checked voltage, at the sender end, there was no pulse, either. It was a solid reading.

Depending on the regulator used, if it has the third spade connection that would normally be for the condenser, it would be possible to connect battery 12v to the regulator where the condenser would normally go and connect the gauges to the normal output lug and you would supply battery voltage to gauges. Effectively bypassing the reg

When you are at the fuel sender, take a voltage reading there as well. Expecting 10.8v but the way this gauge tshooting is going, should be ready for anything..lol

[floorit426]

I checked the voltage, at the tank. You are right, 10.8 non pulsating volts. It would appear my voltage limiter is the culprit? I still don't understand why the other gauges were not pegged, though.