smokes only when down hills?

[caprisecca]

okay so i live in the ozarks, lots of hills and smaller mountains, and theres one i drive down every day. right at 2 miles of coasting and braking, no accel. and ive noticed that every time i accelerate at the bottom of the hill quite a bit of blue smoke comes out. ive started watching and that the only time ive noticed this car to smoke, even at startup, is only when accelerating after decending hills. the longer the hill the more smoke.
i dont believe there is any blowby as my car only uses about a quart of oil every 1200 to 1500 miles. also there are no leaks so this is my only oil consumption.
other information that might be useful to yuns, 230k on motor, and cars is in great running condition everywhere else.... just thought i would ask the pros what yall thought?

[Christ]

When you let off the pedal, the vacuum increases because the engine is trying to suck air past the throttle plate. This causes the pressure in the block to drop, and the oil mist can get sucked into the cylinders if the rings are loose, making blue smoke appear while you're accelerating or when you get back on the throttle.

Generally, this means the block vent and PCV system need maintenance.

Something you can check quickly if it's EFI, make sure you're on a level, accelerate to 60, let off the gas and when the car starts dragging down, momentarily turn the key off, then back on with it still in gear. This only works on EFI with manual trans. It will tell you if you're getting the fuel cutoff. If you can feel the car "stall" when you turn the key off, you're not getting DFCO, and that could also be a cause for your blue smoke issue.

[Larry Hampton]

Is it a standard? Push in on the clutch. Shut it off, but don't turn the key so far you lock the wheel, LOL!!

[FestYboy]

another option that falls into the increases vaccum train of thought is the intake valve seals wearing and allowing oil to mist onto the valve and then into the cumbustion chamber.

[Movin]

If you push the brake pedal enough to turn on the brake lights but not enough
to brake .. It will turn on the fuel cut way sooner and hold it longer than decel.

[Christ]

If you push the brake pedal enough to turn on the brake lights but not enough
to brake .. It will turn on the fuel cut way sooner and hold it longer than decel.

Sweet, just learned how to manually control DFCO

[caprisecca]

okay just to double check whats DFCO mean lol? ... something fuel cut off?

[Christ]

Deceleration Fuel Cut Off. Most EFI cars have it, there are some carb designs that allow for it as well.

Basically starves the engine for fuel when your foot is completely off the throttle. If it's working properly, and you cut the key off for a second, you won't feel the engine "stall". You generally have to be over 2,000 RPM and decelerating through engine drag to engage it (or in some cars, touch the brakes.)