help with temp sender/gauge

[Dave NEO]

With ignition on, I grounded the wire lead to the sensor and the gauge pegged. Also put a voltmeter positive lead to the sender wire and other to battery ground and got pulsing voltage. So per previous posts this said sensor bad.
I replaced sensor and not seeing any action on gauge after a short run. I have a feeling gauge is sticky and I need to run engine longer and heat it up really well. So we'll see I guess. Tried using ohm meter but I'm not good at reading the scale - but it did seem when testing the old and new sensors on the workbench that they gave different ohm readings. With the black lead attached to sensor base and the positive lead attached to the wire connector at the top I think I get what is 10 ohms on the old sensor and 80 on the new sensor which seems to suggest the old one needed replacing if i understand correctly what I have read in related posts on this forum. Comments appreciated.

 

[kiss]

Does your fuel gauge work?

 

[Dave NEO]

yes , fuel and oil pressure definitely working - less sure of ammeter though it seems to be working also.

 

[TrailBeast]

Teflon tape on the sensor?

 

[Dave NEO]

on a few of the last threads...

 

[AJ/FormS]

pulsed voltage on the plus side is normal. That gauge does not work on 12 volts, but rather on about 5 volts. The way Chrysler does this is thru a dash-gauge voltage regulator. You are seeing it in action. It is just a bi-matalic strip that heats up when battery voltage goes thru it. Then it breaks the circuit and cools. This is then repeated endlessly.The result of all this switching is that the gauge sees an average voltage of around 5 volts. The gauge is slow to respond, so normally you don't see this fluctuating.
If your gauge pegs when full ground is applied but does nothing with the sender in circuit, then as others have said. Either the sender is bad, wrong,not connected properly,or not grounding properly. Use no sealer on this baby. It's brass; it doesn't usually take much torque to seal it.

 

[Dave NEO]

got it - thanks !

 

[Dave NEO]

took sender out and got rid of the teflon tape and gauge is working. takes longer than I thought to warm up the engine but it gets there - temp stays pretty low with new big aluminum radiator - not complaining...thanks all for the tips.

 

[AJ/FormS]

The size of the rad should not have anything to do with the the warm up period; that is strictly a function of the thermostat,the AFR,and the initial timing.
The thermostat sets the MINIMUM water temperature. It is always trying to trap the water in the block. Only when the water temp gets close to it's setpoint,does it begin to open. After the engine has warmed up enough to open the stat, the hot water then goes to the rad,and the pump pulls in the cold stuff. If the water temp falls to below the stat's setpoint then the stat begins to close, until the water temp bounces back up. It repeats this endlessly, trying to maintain a very narrow temperature window around it's rated setpoint.If the engine temp goes higher than the setpoint, there is nothing the stat can do about that,it is already wide open. Now the rad,fan system has to shed that extra heat.
>So maybe the stat is faulty,or
Do you think the choke might be set a little rich? Cuz rich will suck the heat into the tailpipe.Ans so will a too-rich low-speed fuel circuit
>If you have aluminum heads those are a real heat sink.
My aluminum heads take about 2 or 3 miles to warm up in summer, after the stat has already opened up, and the gauge has normalized.I can always feel it as the car surges ahead, and picks up 1 or 2 miles an hour.
And last but not least, the factory temp gauge is notoriously slow. I use it only to show trending.

Oh GeeWhiz, you said it takes longer to warm up than you thought to warm up the engine. My mistake. Somehow I read it that it took long to warm up,period. So ignore this post, lol. Sorry to waste your time.

 

[swies]

The size of the rad should not have anything to do with the the warm up period; that is strictly a function of the thermostat,the AFR,and the initial timing.
The thermostat sets the MINIMUM water temperature. It is always trying to trap the water in the block. Only when the water temp gets close to it's setpoint,does it begin to open. After the engine has warmed up enough to open the stat, the hot water then goes to the rad,and the pump pulls in the cold stuff. If the water temp falls to below the stat's setpoint then the stat begins to close, until the water temp bounces back up. It repeats this endlessly, trying to maintain a very narrow temperature window around it's rated setpoint.If the engine temp goes higher than the setpoint, there is nothing the stat can do about that,it is already wide open. Now the rad,fan system has to shed that extra heat.
>So maybe the stat is faulty,or
Do you think the choke might be set a little rich? Cuz rich will suck the heat into the tailpipe.Ans so will a too-rich low-speed fuel circuit
>If you have aluminum heads those are a real heat sink.
My aluminum heads take about 2 or 3 miles to warm up in summer, after the stat has already opened up, and the gauge has normalized.I can always feel it as the car surges ahead, and picks up 1 or 2 miles an hour.
And last but not least, the factory temp gauge is notoriously slow. I use it only to show trending.

Oh GeeWhiz, you said it takes longer to warm up than you thought to warm up the engine. My mistake. Somehow I read it that it took long to warm up,period. So ignore this post, lol. Sorry to waste your time.

I don't think reading the information is a waste of time. I learn more everyday and feel better prepared for the next problem to happen.
Thanks for taking the time to type it out.

 

[AJ/FormS]

Sometimes I think there is something wrong in my head. Rumble chided me yesterday, on my missreading a different post. It's starting to happen more often. At 64 I wonder if I'm losing it, or just getting stupid. Thanks for responding with mercy.

 

[TrailBeast]

Sometimes I think there is something wrong in my head. Rumble chided me yesterday, on my missreading a different post. It's starting to happen more often. At 64 I wonder if I'm losing it, or just getting stupid. Thanks for responding with mercy.

Will you still need me, will you still feed me when I'm 64?

 

[Dave NEO]

fan is an upgraded high perf and no thermal clutch (also not sure if it's even running a thermostat right now) so combined with what you said about these old gauges it makes sense.