Zero oil pressure?

[mjohnson]

I need to diagnose my oil pressure sensing/reading system.

My '78SC suddenly reads zero on the oil pressure gage. Actually, it bounces (like digitally) between 0 and 0.5 bar. The engine had been reading "normal" pressures before this.

The pressure idiot light did not illuminate and the engine ran fine though I did shut it down < 10s after noticing the strange pressure readings (this happened in the driveway).

Short of puking oil straight down out of the oil pump is a zero pressure reading from a 'normally' running engine even possible?

How does the sender work? Is it something like 0V = 0 bar and 12V = x bar? Maybe I can put my multimeter on it while I crank the engine? Same set of questions for the gauge in the dashboard...

Of course this happened immediately after I was screwing with the oil lines. I had a massive leak in the one that goes from the thermostat to the crossover pipe in front of the engine. Once I got that one changed, with all the associated swearing and spilling of blood and oil, I am not happy to see this next problem.

If anyone wants to see a 911 get pushed off a big cliff into the Rio Grande, let me know.

mike
'78SC