Okay, I think this has been hit on before, but I have an aftermarket oil pressure gauge that I want to hook up. The sender unit is 1/8" 27 tp, and of course the location that the oil pressure sender should go is a metric thread. I've read that I should tee it off and have both connected, but that sounds like its more trouble then its worth. I've found the adapters to attached the aftermarket sender, and would like to know how to fool the idiot light into thinking it has good pressure, as the factory sender is just a switch. I can't see the purpose of having both an idiot light and a gauge, the gauge provides far more information, and I think I'm just as likely to notice it as the idiot light.

If you have the adapters for the aftermarket sender, hook up the gauge and forget the IDIOT light. Hooking the light to the gauge sending unit will probably throw off the accuracy of the gauge, and since the light draws way more current than a gauge movement, it could possibly damage the sending unit.

Do I just leave the wire that went to it hanging?

What kind of gauge did you buy?

Its a no name electric gauge, just had to have something better than that light. I have a inkling that my oil pressure might be too low.

Also, anyone know the thread of the current oil pressure sensor on the block right now? I want to say its M12x1.25.

You should be able to unscrew the stock one and about 12" up there should be a plug that you can disconnect, then just tuck the remaining wire somewhere out of the way. That's all i did anyways, i have a mechanical gauge but it works great...very easy install and i actually had the right metric reducer for my application which was nice for a change.

I will do the same, thanks for the info!

You can also get a dual output sender, has both analog pressure output for a gauge and a contact output for an idiot light. I used a dual output VDO sender on my VW.

Oil pressure senders.