As I wrap up my long delayed engine swap and finish up the wiring, I noticed that I have an oil pressure sender wire (for an idiot light) at the back of the engine. However, my car (a '69 RS/SS) has console gauges, so the normal oil pressure port is already used by the tubing hookup for the gauge.

I'm curious as to which of these three is true:

1) My car probably wasn't equipped with console gauges originally, and hence has the wire left unused for the original idiot light, or

2) Cars that had gauges from the factory just left the idiot light sensor wire unused, or

3) Cars with console gauges should have a T-connector to supply both the pressure tubing AND the idiot light sense wire

While (3) might be a good way to go, I'm trying to figure out what the situation would have been from the factory.

Thanks!
Dave

My Guess and I do mean guess is #1

Plus the fact that an oil pressure gauge actually senses oil pressure via the tube (filled with oil) whereas the idiot light just uses a sender that goes to ground when the oil pressure is below a certain point. Grounding the circuit completes the circuit allowing the idiot light to go on.

alan

I guess #1
You could have both, r just tape up the wire and stash it out of sight.

#1
A different Harness was used for RPO-U17 cars ...

I have both gauges connected. I feel that if I don't notice the oil pressure drop on the gauge then the Idiot light will alert me.

Plus the fact that an oil pressure gauge actually senses oil pressure via the tube (filled with oil) whereas the idiot light just uses a sender that goes to ground when the oil pressure is below a certain point. Grounding the circuit completes the circuit allowing the idiot light to go on.

alan

That's my point (and question). Since they work differently, unless you T-d the output, with one side going to the tube and the other to the sender, you can't have both from the single oil pressure port.

But did they really have a different engine harness for cars with console gauges? ie: one that omitted the sender? That's the question.

The sensor wire is part of the stock factory loom, with or without consol.
I do not know for sure if factory consol and idiot light where both connected..
But I do believe from memory (about 25 yrs ago) when the matching engine # got its 1st rebuild...I sure the oil light used to come on on a cold start.
I do not remember pulling a 'T' off behind the dizzy, but do remember purchasing one to use both idiot light and consol????

I do believe?? the maybe another point on the block further down near the oil filter where the idiot light or consol may have connected in??

3) Cars with console gauges should have a T-connector to supply both the pressure tubing AND the idiot light sense wire
While (3) might be a good way to go, I'm trying to figure out what the situation would have been from the factory.

Just do it....A red 'KILL THE ENGINE NOW!!' light on the dash is as far as Im concerned a neccessity.
Several times over the yrs, curuit and off road racing it saved and engine..
And ...I was barralling along at high speed out in the country hill, in the camaro, took a cnr, it had a dip and a hump, the sump dropped om the hump, ripped it open...light came on, turned the engine off even before came to a stop...the idiot light saved an expensive engine rebuild....it happens.

I have both gauges connected. I feel that if I don't notice the oil pressure drop on the gauge then the Idiot light will alert me.

I connected the idiot light wire to a sending unit on the driver's side head and the pressure line for the gauge to a sending unit behind the distributor. I have both types of sending units on the engine.

I had my " kill the engine now " light come on at the 1000 foot mark in my drag car I looked at that and thought huh I nver see that light come on while,Oh s--t .I shut it down ,loaded up ,took it home, took it apart found the pick up tube had broke .I had to put main & rod bearings in turn the crank 10 -10 . I guess if your moter is turning 6700 rpm you don't get much time.

I had my " kill the engine now " light come on at the 1000 foot mark in my drag car I looked at that and thought huh I nver see that light come on while,Oh s--t .I shut it down ,loaded up ,took it home, took it apart found the pick up tube had broke .I had to put main & rod bearings in turn the crank 10 -10 . I guess if your moter is turning 6700 rpm you don't get much time.

......milliseconds?.........:beers:

alan

thought huh I nver see that light come on while,Oh s--t .I shut it down
Sometimes it pays not to "think" 1st...Red light just kill.

I have both gauges connected. I feel that if I don't notice the oil pressure drop on the gauge then the Idiot light will alert me.

I do too and it saved me once when the distributor clamp slipped off and allowed the pump to become disengaged. I have no doubt I would have trashed the motor before I noticed the pressure gauge.

I connected the idiot light wire to a sending unit on the driver's side head and the pressure line for the gauge to a sending unit behind the distributor. I have both types of sending units on the engine.

I have to make a correction: I have the idiot light plus gauge connected for the engine temperature, not the oil pressure. I apologize for any confusion I may have created.

1) My car probably wasn't equipped with console gauges originally, and hence has the wire left unused for the original idiot light. Dave

#1 is the winner - the factory harness was unique when console gauges were specified, and didn't have the circuit for the oil idiot light wire. :thumbsup: