Temp gauge seems to read too low

[BS23VOB_FJ5_Faker]

My temp gauge in the rallye dash reads just on the line above the C when the car is up to temp and the fluid is at 185-190.  I expected it to read near the center.  Is this an issue, and would a new sending unit be worth a try?  I don't want to put aftermarket gauges below the dash, but I don't know if I can rely on the stock ones.

[Bullitt-]

Ground the wire that connects to the sending unit & see if your gauge pegs, That will tell you if the gauge is good or not, if that proves out clean contacts & connections & finally replace the sending unit.....Make sure you have a good motor to battery ground as well.

[MEK-Dangerfield]

Your gauge reads the same as mine at operating temperature. It shouldn't be halfway. These aren't like modern cars.


  Mike

[GregGarner]

You can also measure the resistance of the sending unit. It should be 80 Ohms or more when cold, and at max temperature it should be 10 Ohms. 10 Ohms
makes the gauge read full scale.  If all the gauges read low, then the limiter can also be at fault here. See here for more info on gauge testing:

http://rt-eng.com/mediawiki/index.php/RTE_Gauge_Faq

Greg Garner
www.rt-eng.com
1-479-756-2757

[BS23VOB_FJ5_Faker]

I bought 3 new temp senders from different sources. 2 of them cost $5 each from autozone and NAPA.  the third one I had high hopes for because I got it from Mopar Parts directly, and it cost nearly $30.  An ohm test was done with a pan of water on its way to boiling, a Raytek infra red temp gun and a fluke multimeter.  Keep in mind that this is a single sample of something made in China by the lowest bidder, and the test isn't conducted under the most scientific of conditions.  The results of the ohm testing and real world use are below:

Temp of water  (F)   81          160          210

Mopar                    222.3      74.2         38
Autozone               172.5       48,4         31.7
NAPA                    166          46.3         30.8

The NAPA part and the Autozone part looked IDENTICAL, and each worked better for me in my car.
In my opinion the Mopar part was a big waste of money, and did a poorer job in my particular car.

I guess I will just watch to be sure it doesn't go ABOVE the line above the C while I am driving.

PS, my gas gauge isn't working, but my oil pressure gauge seems fine.

[buzzard]

 Maybe you got regulator prob. yes/no. Maybe you should check the low voltage on the cluster. Good luck

[Chryco Psycho]

typically 190* is approx 1/3 on the guage reading just above the second line

[cowboy]

-
Mine also only lift very little over buttom, I changed the sending unit to a new one, - but its the same..
When I ground the wire  at the sending unit, it read top.....

[BS23VOB_FJ5_Faker]

The super high tech illustration shows what i have going on.  If I ground the sender wire momentarily, it pegs the gauge.  On cold start up it looks like the blue line.  When up to running temp at about 185f it looks like the orange line.  When I shut it down and it heat soaks to about 210f it looks like the red line.  It sounds like I have it reading a little low, but working.  When I get to that part of my to do list, I will give Greg at RT Engineering a call and go through the whole cluster.  Until then, I will just watch that it stays at the orange line.

P.S,  How much of a pain is it to pull the rallye cluster out of the 70 Cuda? 

[MEK-Dangerfield]

The super high tech illustration shows what i have going on.  If I ground the sender wire momentarily, it pegs the gauge.  On cold start up it looks like the blue line.  When up to running temp at about 185f it looks like the orange line.  When I shut it down and it heat soaks to about 210f it looks like the red line.  It sounds like I have it reading a little low, but working.  When I get to that part of my to do list, I will give Greg at RT Engineering a call and go through the whole cluster.  Until then, I will just watch that it stays at the orange line.

P.S,  How much of a pain is it to pull the rallye cluster out of the 70 Cuda? 

My gauge is the same as your's. It is operating normally.


  Mike

[cowboy]

On cold start up it looks like the blue line.  When up to running temp at about 185f it looks like the orange line.  When I shut it down and it heat soaks to about 210f it looks like the red line.

 

[BS23VOB_FJ5_Faker]

Thanks guys.  It sure seems like a lot of gauge left over.

[vinb]

Your Orange line is 165-168' on mine with a 160 stat and the thermometer in the radiator...

[miketyler]

I have the rallye setup in my 72 Cuda and recently bought a new electric gauge to compare it with. Am running both side by side and when the factory gauge is horizontal the other gauge is showing around 210* or so. I had one other person with the same setup and he made the same observation.   

[Mopar73340]

  Mine is the same way 210-215* for the factory guage to be horizontal.