Testing Gauges

[GILDIA]

Hi, does any body knows how to test the OIL/TEMP gauge, i can't get a single lecture from them.

Thank you

[EScanlon]

Both require the sensor mounted on the engine for readings.

If I recall correctly, they are both resistance sensors. As such, if you connect the Yellow/Red wire to 12v+ and the Yellow/White to ground, the gauges should "Max" out, that is, read all the way to the right.

HTH

E

[RogerZ]

take the wire off the sensor turn on the ignition. ground the wire gauge should max.

[beandip]

I wanted to see just what mid range was in lbs. on my oil pressure gauge so I installed a mechanical gage . In my case the mid position reading is close to 50lbs, and 1/4 off the zero is about 25 lbs . this is where my engine runs when at idle and normal temp. The temp gage use either a candy thermometer in the top tank of the radiator or one of the infrared sensors on the market. Either will work fine , just keep the glass from touching the metal of the Rad. Gary

[GILDIA]

Thank you guys, I will try it, what if when i ground them they wont read? does that mean that I will need a new gauge?

[EScanlon]

These are pretty simple gauges, simple analog dials. Check the obvious; power and ground connections. Past that.... you might want to find replacements.

2¢

E

[GILDIA]

Thanks E, regarding the power it feeds through the VR, and it just goes directly to the oil and temp sensors.

[EScanlon]

Exactly, the gauges make ground through the sensors in the engine block. As the resistance of the sensors changes the current flow changes as well causing the gauge to deflect more.

An interesing note here, I don't have the information as to whether the sensors increase or decrease resistance as the pressure/temperature changes. This might be a good point for someone to point out.

Hope this helps

E

[geezer]

An interesing note here, I don't have the information as to whether the sensors increase or decrease resistance as the pressure/temperature changes. This might be a good point for someone to point out.

Hope this helps

E

E, I don't have a lot of experience working with or testing these gauges but I know that less resistance will result in a higher current flow, which will make the gauge read higher as the temperature or pressure rises. So yes, I would say the sensors decreases resistance as the temperature or pressure rises.

[GILDIA]

So, if i ground the sensor wire, i should read maximum?

[EScanlon]

Yes.

What I was asking, that Ron answered, was whether anyone knew whether the sensors increased or decreased their resistance as the temperature/pressure went up. Since higher temp usually results in higher resistance (at least as far as electricity is concerned) it's not automatically intuitive.

E

[GILDIA]

I just ground the but i am not getting any lecture from it, do you know what is the voltaje I should get from the VR...