I've seen xviper's writeup where he used a t-fitting to attach both the stock oil pressure sensor and the sending unit. Is it possible just to use a straight fitting and do away with the stock sensor or will this cause problems?

 

The car's ECU needs that stock sensor signal to run the car. Without that signal, I'm sure the ECU will have a brain fart and crap all over your parade.
Now the interesting experiment: See if the ECU will accept a spice off the new sender. I can't say for sure if the doing this will be recognized by the ECU or how it will affect the accuracy of your new gauge.

 

i disconnected the wire going to the stock sensor and drove it around. so far no check engine lights or any other problem.

 

This is very interesting. At the very least, you oil light should have come on. Did you tape the end of that wire so it doesn't touch any metal on the engine?

 

yes its taped. no problems yet.

 

If that's the case, then go for it. I just checked the Helm manual. With the stock sensor wire disconnected and taped like you have it, your oil light will never come on, even when it should (like during the initial ignition "ON" test sequence). The ECU will always think that there is oil pressure (even when there isn't), so all should be well. Just don't count on the oil light on the dash to tell you anything. But then, that's why you have the aftermarket gauge, right?
I should learn to always check the Helm manual before I make assumptions.

 

You should see if the 'OIL' light comes on with the ignition 'ON' but the engine OFF. If it does not come on, then you are preventing the ECU from seeing a problem later. I believe the stock oil pressure switch is just a switch (on / off), and it may be that the switch is open when there is oil pressure, and closed when there is no pressure.

 

This is exactly the case. I just cannot say with certainty if the ECU will kick up a fuss if it never sees a "confirmation" light on ignition test. Only time will tell.

 

If it were me, I would want the blinking CEL if my oil pressure suddenly dropped. You may not notice the guage, unless it has a blinking light.

 

well its all hooked up. The gauge goes up to 100 psi. The initial reading cold was 100 then it dropped down to 50. It goes back up to 100 around 3500 rpms. Sound right?