I have new aftermarket gauges on the way and I started to read about hooking them up but I couldn't find a really good solution for the oil pressure gauge. The car is a '91 with a 305 TPI. I read that the pressure sender above the oil filter is also a switch for the fuel pump. From what I understand, if you remove the original sending unit and plug, the fuel pump wont see oil pressure and wont turn on. What is a way that you have gotten around that when installing your gauges? What is the usual way that an aftermarket oil pressure gauge is hooked up on these motors?

Thanks!

 

I recently had an oil sending unit scare on my 85. I went ahead and installed a tee and 1" oil pressure guage as cowitness to the dash guage. Perhaps you should consider a "tee" for your secondary oil pressure reading?

 

that's a good idea as well, then there's no messing around or wondering if unhooking the plug will mess something up.

 

Not exactly. It's a backup circuit only. Normal operation has the fuel pump power going through the relay. The oil pressure switch keeps the engine running if the relay dies.

Not sure why the factory did it that way, doesn't make much sense to me.