Thread: Oil Pressure Gauge Help???

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The particulars:
1967 Ford Mustang
390ci

Instrument panel has Tach with clock in upper center gauge location (non-working).
Currently an oil idiot light is located within the Tach (lower left location)

What I wanted to do: remove clock and install a stock oil pressure gauge in its place.

Friend gives me a working Oil Pressure Gauge (OPG) that would be a natural fit in the clock location.

Oil sensor (button like sensor, coarse thread) is located on the top of the oil filter housing.

UNDER-HOOD
1: remove WHITE with RED stripe wire attached to threaded top of button style oil sensor (90degree connector).
2: remove button style oil sensor
3: install Oil Sensor for oil pressure gauge equipped cars (canister type with coarse thread attachment and small threaded post at the top.
4: re-attach WHITE with RED stripe wire to top of small threaded post atop oil sensor.

INSTRUMENT PANEL
After removal of panel to gain access to gauges.

1: detach wiring to clock, Remove clock
2: install OPG in its location (adapted a mounting system that hold gauge in place, made of plastic)
3: cut WHITE with RED wire going to Oil idiot light and attach to right post (as looking down from above) of the OPG
4: Tap off of the constant voltage regulator (using spade connectors) on back of speedo (for power) and attach this wire to left post (as looking down from above) of OPG.

Problem:
Upon moving starter switch to ON or STARTING engine, OPG does not move.
OPG can be grounded separately and the needle will swing fully, so OPG works.

I have been through 3 Oil Sensor switches (canister types). All the same outcome.
I have been told that these sensors should have a ohm resistance of 20-80ohms.
Is this with the engine running and the sensor in its place?

I even tried running a wire directly from the top post of the oil sensor to the right post of the OPG (by-passing any old car wire problems) and still no movement of the OPG.

Is there something special about a 390 oil sensor that I’m missing?

Can some-one direct me on how to connect a OPG what was a Oil idiot light car?


I’m not educated in the electrical ways of things so talk to a simple mind (tab A into slot B type).

Thanks for any help.


Mike

Is there continuity on the white w/red wire? I think if you ground the white wire at the sender, with the wire connected at the OPG, it should peg the needle. The same as when you grounded the gauge.

my other question is to verify the sending unit your unit is for a gauge not a light... And who's gauge? Name brand?

Mike,
Welcome to CHR, and as you're finding out we're not so hung up with things being in the right section around here, unlike some "other places", but one thing that riles folks is to have the same thing posted in several places, because they all show up when we hit "Today's Posts". You might want to PM a Moderator, like mrmustang, and ask that the second thread be deleted - just a suggestion.

Like Mike (34_40) said, check your continuity on the white/red wire, either with an ohm meter or using a test light. I suspect that your "idiot light" used the low pressure switch as a path to ground, with power being supplied to the lamp at all times, just waiting for the low pressure to complete that circuit. Your new sensor is a variable resistor which changes with oil pressure. It is grounded at the connection to the block (you cannot use a full coverage of teflon tape or sealer, as it will insulate your connection. A wrap on the bottom couple of threads is OK if you have to have it). As you have done, power to one terminal of the indicator, and the other side hooked to the sender. Are your OPG connections marked?? If not and if you have a good ground at the block you might try reversing your connections at the gauge and see if that might be your problem?

Sorry for the double posts. I'm guessing I did it between work assignments (yes I'm at work) and forgot I did it. I really thought I was in the FE forum each time I logged in (odd).

I'll only reply over on the FE forum so not to complicate the mess I made.

My apologies again.