Oil pressuer sending unit & gas mileage

Factual Questions
#1

In January my 83 Corolla (carbureator, no fuel injection for Inigo!) started leaking oil. Not a little bit either. Tons. Barrels. Like 1 quart in 2 days. Made a helluva mess lemmee tell you. Fuel economy plummeted at the same time from 35mpg down to 25. 'twas cold this winter, and dark when I’d get home so I didn’t have a chance to explore for the source until April. I’m thinking, “Please God, just the pan gasket. No head gaskets or seals–I’ll go back to church, but please, just a pan gasket. That I can handle…”

As I’m opening my hood (or bonnet for you UK Voyeurs) my neighbor, the 6’3" 250# retired factory worker turned classic car restorer named Hans, rolls over and booms, “Whassa matter with your buggy?” “Bleeding oil like it’s been gut shot.” (he appreciates this kind of talk, makes it OK that I wear nice clothes to work and don’t drive a pickup) “Anything else?” “Gas mileage sucks now…” Leans into the gaping maw of my sporty 2-door import and regards my simple 4-banger, the only attachments to which are an alternator and the aforementioned carb & aircleaner. There’s room for a small child in there as well, but none today. “Hmm…Oil Pressure sending unit. It’ll run you $5?” I’m skeptical. “Would that affect the gas mileage?” “Dunno why. Always does though.”

I replaced the part (only $3) and sho’ nuff the leak stopped and the gas mileage bounced right back to 35mpg. Throughout the leaking period I never let the engine get more than a quart low (only holds 4) because the prospect of buggering my engine didn’t appeal to me. And while it was quite cold at times this winter I noticed no difference in fuel economy any previous winter, so I’m inclined to rule out the cold as the OPEC ally.

So. Now the question. In an older engine with a rudimentary computer, if any at all, can the failure of an oil pressure sending unit adversely affect fuel economy?

#2

I doubt there’s any relation at all, but I’d be interested to know if there was. It’s like you urinating, and for some reason, you forget your multiplication tables every time you piss. Doesn’t relate you know?

#3

Ummmmmm…yyyyyyyeeaaah. Something like that. :dubious:
I used to own a Nissan pickup. When the O2 sensor failed the computer decided a good thing to do would be to run the engine super rich. So much gasioline was entering the cylinders that some was getting squeezed out past the rings and into the oil (my mechanic told me this–I won’t be embarrassed if someone starts laughing). The oil had thus been thinned so much that it was exploiting a weak rear main seal and had caused it to leak some. The leak went away after I replaced the O2 sensor and the oil, and the fuel economy improved with the replacement of the sensor. I suspected the same thing was going on with “Muh muh muh my Corolla” until I relaised it wouldn’t have an O2 sensor.

#4

I’ve never heard of oil sender leakage affecting fuel mileage, and I don’t see how there could a cause/effect relationship.

#5

I replaced a jillion oil pressure sender units on the old aircooled VWs. I never heard anyone comment of gas milage vs. sender unit either pro or con. I don’t see a connection at all.