wiring question

[MHunter]

Is there a wire I can splice into that is +12v only when the engine is running?

Thanks,
MH

[crafty]

No.... but if you want something wired this way, put an oil pressure switch in a spare hole, run -ive to there and +ive to to switched power. When the oil is moving it provides earth.

[Steve_D]

Depending on how much power you want to use I would suggest using a relay and, as Crafty said, use an oil pressure switch to drive the relay.

You will also need to consider if you have an Accusump your new supply may come on as soon as you turn the ignition because the Accusump will raise the oil pressure.

If you have EFI you may be able to use the fuel pump relay as that will only be on when the engine is running apart from a few seconds prime pulse just before start-up.

Steve

[MHunter]

any way I can spliced into the oil pressure sender already installed and use its variable voltage to run a relay? 0 volts = relay off, any voltage above a certain small treshold = relay on?

[Steve_D]

MHunter said:

any way I can spliced into the oil pressure sender already installed and use its variable voltage to run a relay? 0 volts = relay off, any voltage above a certain small treshold = relay on?

With a custom made electronic circuit...Yes.
But seeing as neither of us know how to build such a circuit then ...No.

Simplest it to add a tee fitting where your sensor is and hang the sensor and a switch off it.

Steve

[spatz]

what do you want to do ?

[MHunter]

I'm trying to get the headlamps (driving light, or parking light) to turn on when the engine is running. requirement here in canada. Daytime Running Lights.

I could just have them turn on when acc. are on, but I was hoping for a cleaner install if it is simple enough.

[Steve_D]

MHunter said:

I'm trying to get the headlamps (driving light, or parking light) to turn on when the engine is running. requirement here in canada. Daytime Running Lights.

Why not just power them from a relay connected to the ignition switch?
If you connect to the auxiliary position they will be switched off during cranking but onat all other times.

Steve

[spatz]

ok I think you should keep this a manual switch, or as mentioned before wire it with a pressure oil switch if you are using
an old SBC or even more simple using the fuel pump relay switch of the ECU.

[Steve_D]

MHunter said:

Is there a wire I can splice into that is +12v only when the engine is running?

Thanks,
MH

None that I know of.

Steve

[60mph]

Your headlights will go out when your oil pressure fails . At least this way you won't have to keep looking at the gauge !

Frank

[MHunter]

60mph said:

Your headlights will go out when your oil pressure fails . At least this way you won't have to keep looking at the gauge !

Frank

Yep, they'll be like 2 huge oil pressure warning lights. But now I wonder why you used the word "when" instead of "if"...

[60mph]

I was assuming that you would not have an AS engine ! Otherwise 2 huge warning lights not required . [joke]

Frank