Oil Pressure Gauge Help???

Thanks.

The gauge is a 1967 Ford Mustang. The sensor was changed from a button type (sensing 5psi or lower) for the idiot light to the cannister type which Ford had used for years (uses a resistor).

The gauge is a two post type. One for the stepped down power of 5 v and the other going to the sensor. I'm told less resistance in the sesnor more power to the gauge...needle moves.

It seems that power is going through all the right places which points to the sensor/sending unit. I was hoping I guess that some-one would slap me and say you forgot.........something......but. I guess more tesing is needed to track down the problem.

Quote:

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Originally Posted by kbmwgt

Thanks.

The gauge is a 1967 Ford Mustang. The sensor was changed from a button type (sensing 5psi or lower) for the idiot light to the cannister type which Ford had used for years (uses a resistor).

The gauge is a two post type. One for the stepped down power of 5 v and the other going to the sensor. I'm told less resistance in the sesnor more power to the gauge...needle moves.

It seems that power is going through all the right places which points to the sensor/sending unit. I was hoping I guess that some-one would slap me and say you forgot.........something......but. I guess more tesing is needed to track down the problem.

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I would think you could check your sending unit pretty easy, but it might take a second pair of hands or some aligator clips on meter leads. Put an ohm meter on your sending unit from the output terminal to the case and you'll see resistance. Then set your air supply regulator to say 40psig, put a nozzle on the hose and blow that pressure into the end of the sending unit. Should see a change in resistance, right? Seems logical to me, but could be too simple?

do you have the sending unit for the guage you are using???????????If no then I would get it and quit guessing. If yes call or go to them and get the directions..... maybe you should just not use the ford harness as its is not working for you???? An op gauge is as easy as adding a light to the trunk.

5v is a computer type thing---you don't have the correct matching parts--simplest way for me to tell you to fix it is to buy a guage/sender combo from an reputable company---or go to a mech guage because you are coming up short on the PIE stuff----

Quote:

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Originally Posted by jerry clayton

5v is a computer type thing---you don't have the correct matching parts--simplest way for me to tell you to fix it is to buy a guage/sender combo from an reputable company---or go to a mech guage because you are coming up short on the PIE stuff----

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Jerry's right (as usual), if your gauge is a 1967 unit it's going to be looking for a 12V feed with the variable resistor controlling the current. Sounds like maybe you have a more modern sending unit, meant for an ECU vehicle? Where did you get the 5V information?

He may be correct as many fords used a resistor for their gauges well into the 70's! You can use gauges from a 70's pickup and insert them straight into a 48 f-1 !

If he's using a ford gauge and a ford wire and a ford sending unit, it should (in theory) WORK! Unless there is an optional gauge cluster in the center of the dash or some other wires have been "re-purposed?!?!?

Maybe try a separate (new) piece of wire to run from the gauge to the sending unit and eliminate all the other stuff as a test? I never heard from him if he did test the wire by grounding at the block the connection that would go to the sending unit and what those results were.. or did I miss that?

Going to try that this weekend.