Oil Pressure Goes to Zero!

[ballencd]

There is no mechanical interference on the wire. Picture looks like they touch but they are far apart.

Interesting......today I pulled the dash and wiggled all the wires, moved the tach wire away from the rest, reseated a few wires and the problem for now has gone. I reinstalled the dash and tested a second time....all good. I didn't drive it but let it idle to warm up....it may need to be run on the road as it gets hotter on the road. It was not real hot today either....like 88 vs 95. I will follow up if it comes back. Thanks for all the replies.

 

[Bextreme04]

Just woke up and thought of this. What do the other gauges do? When the oil pressure drops. It could just be a ground. Electrical problem and we are 2 pages in and first mention of a ground. But, there were labatory dicks swinging around and laws being written.
What do the other gauges do?

Loss of ground would cause the gauge to peg to full. Losing the ground would cause infinite resistance(broken signal wire is the same thing) which in this gauge is a max signal. 0 PSI reading is from 0 resistance... which would be a short to ground(either internally in the sensor or externally in the signal wire) or possibly a loss of power/ground at the gauge cluster. Since the rest of the gauges share the same power and ground feed and the issue only happens when the engine is hot and in reverse, it's probably not that.

 

[heavychevystuff]

i had a 1993 big blazer with over 200,000 miles on it....
so same exact motor as our squares.
same issue.

it would drop to 0 when the engine was hot.

i installed a whole new oil pump and it didnt fix it. i was so pissed.

what fixed it was adding a bottle of lucas....
after that; running 20w50 oil

it just needed that heavy **** to fill out all the galleys and worn out tolerances of a clapped out old engine. thats why they NEED zinc in the oil to get to 250,000 miles properly, and beyond.

but yeah. just run thick AF oil, or, add Lucas each time.

 

[ballencd]

The gauges have not failed again since the wire wiggling. The engine only has about 130K on it but I do run Lucas and 15-40 Rotella in it already. I think is was a loose wire.