oil pressure sending units specs

Greetings! This is my first post on 12Volt, and I'll be frank: I've run out of ideas. And I have little hope that anyone will have an answer for this. For the life of me, I cannot find any, detailed, technical information on oil pressure sending units. Truthfully, I have that problem with other sensors, but have worked through it so far. I mean the kind of specs an engineer would want when designing a system...because that's what I'm doing. At this point, your first question is year/make/model? Rational question. But it won't work here. The "application" is a 1970 Cadillac Eldorado. And I do not want the original part. I want to replace the factory oil pressure switch (among others) that simply closes when pressure drops to between 3 - 9 psi and activates an idiot light. The car, at 30mph will reach a minimum of 35psi. At 40psi, a relief valve opens. At idle, it should maintain 10psi. The original switch has a 1/4" 18 thread NPT base. I almost know enough to build a sensor from scratch. What I want is to find a modern sending unit, that fits the existing boss and covers the pressure range of the car. Most modern cars have much higher oil pressure. And it is fine if the unit goes higher than what I need. Also, unlike the factory switch, I want a modern unit that operates at TTL logic levels (I.e. 5V reference). Not the highly fluctuating battery voltage (14V average, 8 - 20V not uncommon, much higher possible peaks). I cannot find a human, web site or database that either make it possible to choose an appropriate unit OR wiring diagrams that tell which pins on a given unit do what, if it is resistive, current or voltage based, what the value range is, what psi a value equates to, etc. Apart from finding units that fit in the hole, I can't find a single useful detail beyond that. I've even emailed manufacturers who politely refer me to a local dealership for my "service needs". If anyone can point me to any kind of technical resource, I'll dance a jig. Otherwise, I will have to randomly sample units, figure out which pins are for what and pressure test them to gather value range data. Doable, but expensive, time-consuming and irritating. Thank you for your time! Brandon Gohsman

Oil pressure sending units are matched to their gauges. Once you have a gauge set up, there are different methods of extracting a voltage to feed other circuits.

hi, http://autometer.com/cat_accessoriesdetail.aspx?vid=27...need an adapter for threads however. also look here:...http://www.kavlico.com/kavlico-pressure/downloads/data-sheets   and finally here: http://sensing.honeywell.com/index.php?ci_id=3108&la_id=1&pr_id=31582 maybe one of those will help; mark