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Help finding resisor values for oil pressure and oil temp sendors — Parallax Forums

Help finding resisor values for oil pressure and oil temp sendors

mosquito56mosquito56 Posts: 387
edited 2009-10-21 16:31 in General Discussion
· I am trying to find info on the resistor values of various engine senders. Is there any way to find the various values for various senders?
Vdo values would be a good start. Thanks.

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Comments

  • stamptrolstamptrol Posts: 1,731
    edited 2009-10-20 17:24
    They vary in value from manufacturer and from engine to engine. And, not all of them are resistive.

    Best source of info is a service manual for the car in question. Check out Google, auto parts store or your public library.

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    Tom Sisk

    http://www.siskconsult.com
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  • James LongJames Long Posts: 1,181
    edited 2009-10-20 17:27
    Most industrial sensors send out a value of 4ma-20ma for pressure. I'm not sure about temperature senders.

    James L

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    Please note: Due to economic conditions the light at the end of the tunnel will be turned off until further notice. Thanks for your understanding.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2009-10-20 18:15
    Having rebuilt sveral cars back in the 80s/90s I have found that the sending units vary greatly in value and function. I had some that were resistive, and others that were proportional voltage. Of the voltage units some of them simply were on/off at a preset point. Because of this and my need to interface to a microcontroller I replaced several sending units with ones from other models and/or manufacturers and often had to use adaptive fitting to make things work. I would say empirical testing is going to become necessary here.

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    Chris Savage

    Parallax Engineering
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  • ercoerco Posts: 20,260
    edited 2009-10-21 16:31
    I tested some several temp senders years ago, I just bought a few universal types from Pep Boys. They were all less than 1000 ohms, many around 200 ohms at room temp. They appear to be just simple thermistors, designed to be read by a calibrated milliammeter at 12V.

    As Chris mentioned, some oil pressure senders are just switches for idiot lights, normally on, and they switch off at low PSI. Usually 2-10 psi, so it's more of a low/no oil condition, especially when you are cornering hard and the oil sloshes away from the pickup screen in turn 5 at Riverside raceway in my decambered '67 Corvair Monza 140 4-speed with a 3.55 diff ...

    That got my heart racing for a moment, if not the car.

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