Coolant temp sensor test ( Lenny )...

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T.Hanson
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Joined: Wed Jul 26, 2006 7:39 am

Coolant temp sensor test ( Lenny )...

Post by T.Hanson »

Read your previous post: Testing coolant temp sensor, resistance readings.

Electric neophyte. I have a Fluke multimeter. Set it on Ohms, resistance, horseshoe symbol.

Take the red probe and black probe,...and put them where, and do what ? ( To read the window gauge to see the numbers you listed.)

Thank you,
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sd-mk2
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Location: San Diego, CA

Post by sd-mk2 »

you have an interesting way of writing my friend.
you always have useful info though thanks! :D
1980 BMW 528i, 1987 VW GTI, 1987 VW Golf GL, 1974 Alfa Romeo GTV 2000
T.Hanson
Posts: 1696
Joined: Wed Jul 26, 2006 7:39 am

Post by T.Hanson »

I know, and I wish I didn't when it gets so obtuse nobody can follow it to answer the question.

No offense intended to the experts. Years of knowledge has a way of assuming everyone speaks acronym, or knows righty tighty, lefty loosey.

Wrong.
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Lenny D.
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Post by Lenny D. »

Select Ω (ohms) on your meter.

That setting is measuring resistance in a circuit. The circuit consists of one of your leads carrying voltage from the power source (the batteries inside the meter) through the circuit to the other lead. If there is no load (touch the two leads together) watch the meter eventually settle on 0.00 Ω indicating there is no resistance in that circuit.
Now introduce the CTS into the circuit. It is basically a temperature controlled resistor that is variable (a thermistor). It has a range. Whatever numbers I posted is that range from cold to operating temperature. At whatever temperature the sensor is sensing is the number that is displayed on the meter measuring resistance in the circuit. Simply remove the connector, touch one of the meter leads to the connection point on the sensor you just exposed. Since the body of the device is ground, touch the other meter lead anywhere on the sensor that is metal (and why engine ground is so important, all the sensors are configured this way). That should produce a reading on the meter indicating the resistance (ohmage) that the circuit is producing. If the sensor is operating properly the number should correspond with the temperature of the sensor that the reading is producing to the table listed at the various temperature settings.

There'll be a quiz... :?
HTH

'80 528i
T.Hanson
Posts: 1696
Joined: Wed Jul 26, 2006 7:39 am

Post by T.Hanson »

Thank you.

Darned if searching the web doesn't offer expanded, if generic, solutions to fuel injection problems.
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