Oil Pressure Goes to Zero!

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

ballencd

Full Access Member
Joined
Aug 30, 2013
Posts
106
Reaction score
46
Location
Columbus, NC
First Name
Charlie
Truck Year
1988/1991/1983
Truck Model
V10 Suburban/V1500 Suburban/M35 bobbed w/dump
Engine Size
5.7/5.7/LDT 465-1c
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

Full Access Member
Joined
May 13, 2019
Posts
4,135
Reaction score
4,983
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
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

Junior Member
Joined
Aug 21, 2020
Posts
14
Reaction score
6
Location
usa
First Name
erick
Truck Year
1979
Truck Model
c20
Engine Size
454
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

Full Access Member
Joined
Aug 30, 2013
Posts
106
Reaction score
46
Location
Columbus, NC
First Name
Charlie
Truck Year
1988/1991/1983
Truck Model
V10 Suburban/V1500 Suburban/M35 bobbed w/dump
Engine Size
5.7/5.7/LDT 465-1c
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.
 

Forum statistics

Threads
41,848
Posts
903,418
Members
33,362
Latest member
Dhatch84
Top