Why oh why. Sudden oil pressure drop.

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Kent mosby

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I just installed a new WBO2 sensor and took the scamp for a quick ride. I took a datalog and oil pressure was great. I stopped the datalog as I was approaching home and noticed as I am pulling into the drive that oil pressure dropped to less than 2 psi. What could have happened with such a quick pressure drop? Tomorrow I plan to pull the distributor and spin the pump to check pressure and inspect the shaft before I start it up again. I can also install an analog gauge if I do not get pressure from the dash and efi sensors. Restarting the car for a few seconds repeated the low reading. My thoughts are stripped gear, plugged orifice to sensor. I recently changed the oil so the filter cannot be blocked. Which would strip first, the shaft going into the pump or the pump itself?
 
Low oil level will do that.

When inlet gets uncovered by a turn, or an incline or rapid stop

Might have a crack or leak in the pickup if the oil level reads normal.


As for intermediate shaft... IIRC the shaft turns the pump and the dist, if the car ran normal after oil pressure drop the gear is turning.
 
Oil filter on the front of the engine. Spin it off and cut it open.

See what's in there, steel shavings or aluminum? Might tell you where to start looking.
 
Let's see: EFI, onboard computers, electronic sensors, electronic gauges.

See a pattern here?

Spin in one of these shorty mechanical pressure gauges and see what you got.

Betting it's bad electronics for it to drop to nothing out of nowhere.
Screenshot_20220630-203827_Gallery.jpg
 
Was part of the data log running the **** out of it? Possible valvetrain failure, slinging out a lifter? Just spitballing worst case..... Hopefully it's electronic as others suggested.
 
Here's what I would do, pull the intermediate shaft out, insert a priming rod attached to a drill
in the pump, detach oil line from gauge and point it at your eyeball, now operate drill and pray you get shot in the eye with a pressurized stream of oil. lol
the trick is having the line pointed at your eye, if it's not you know there won't be pressure.
 
Do not fire up that engine again until you know the pump is supplying good pressure.
 
Let's see: EFI, onboard computers, electronic sensors, electronic gauges.

See a pattern here?

Yes but both gauges have separate sensors. For both to fail at the same time would be awfully coincidental
 
Was part of the data log running the **** out of it? Possible valvetrain failure, slinging out a lifter? Just spitballing worst case..... Hopefully it's electronic as others suggested.
No I was just running around. Top rpm might have been 4000rpm
 

Chances are higher than you think.
Grounds are common. I had a short which only burned one small ground wire at my battery that caused all kinds of havoc.
 
Chances are higher than you think.
Grounds are common. I had a short which only burned one small ground wire at my battery that caused all kinds of havoc.

I will check first with an analog gauge and track down the electrical if needed.
 
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