Runs better with oil cap off??

Engine, ignition, fuel, cooling, exhaust

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krogge
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Joined: Tue Apr 25, 2006 2:40 pm
Location: Colorado

Runs better with oil cap off??

Post by krogge »

Hey everyone :)
I've got a 72 f100 (390). I noticed today that the truck has significantly more pick up from the start, and even shifted better (auto trans). Then I started to smell oil burning off from engine compartment. I opened hood to check it out and oil cap had been left off from oil change (yesterday). Replaced the oil cap and truck immediately went back to "normal" running conditions, but not nearly as peppy as when oil cap was off.... any ideas??
Thanks !! :)
Dwell on the good stuff and you'll always be happy, dwell on the bad stuff and you'll always be angry. Be happy.
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Busboy
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Location: Nampa Idaho

Re: Runs better with oil cap off??

Post by Busboy »

When the oil cap is off it creates a little bit of a vacuum leak from the pcv valve. It might indicate that your overall fuel mixture is slightly rich.
1967 F-100 4x4 custom cab.
Another 67 F-100 4x4 custom cab.
2016 F-150 Eco-Boost 2.7 liter. (It will smoke the tires!)
1972 F-350 Sport Custom cab & chassis.
1972 F-250 Explorer Special, Camper Special.
1971 F-100 custom. 302, C-4, p.s. p.b. factory 65 amp alternator with transistorized voltage regulator.
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