Effects of killing one injector - 4 cylinders

[hayden55]

Odd thought as my googling was unsuccessful. With a lot of real world experience with friends running Hondas basically tractoring down the road with one dead cylinder, two dead cylinders, and one time an amazing three cylinders down. What would killing one cylinder do? I assume if you killed the injector to keep the fuel from pumping instead of just killing the spark like what typically happens... Could you three cylinder it and get better mileage?
DIYactivecylindermanagement?

[RedDevil]

The 'dead' cylinder would pump fresh air into the exhaust, so the lambda sensor will sense an overage of oxygen and the EFI computer will try to compensate by injecting extra fuel into the other cylinders.
So just disconnecting the injector is no good.

However, if you close off the intake port of the dead cylinder that will be drawing a vacuum instead of pumping air. That way it has as little friction as possible. Then it would run more or less smoothly.
The vacuum will draw some oil into the cylinder head. Maybe it seeps back into the oil pan when the engine is at rest, otherwise the buildup may cause trouble.

[Frank Lee]

Originally Posted by hayden55

Odd thought as my googling was unsuccessful. With a lot of real world experience with friends running Hondas basically tractoring down the road with one dead cylinder, two dead cylinders, and one time an amazing three cylinders down. What would killing one cylinder do? I assume if you killed the injector to keep the fuel from pumping instead of just killing the spark like what typically happens... Could you three cylinder it and get better mileage?
DIYactivecylindermanagement?

Should be simple enough for you to pull the wire off an injector and run it. If the CEL freaks you out stuff a resistor in the connector.

[oil pan 4]

It only works in engines with hydraulic lifters.

[JSH]

Originally Posted by hayden55

Odd thought as my googling was unsuccessful. With a lot of real world experience with friends running Hondas basically tractoring down the road with one dead cylinder, two dead cylinders, and one time an amazing three cylinders down. What would killing one cylinder do? I assume if you killed the injector to keep the fuel from pumping instead of just killing the spark like what typically happens... Could you three cylinder it and get better mileage? DIYactivecylindermanagement?

For cylinder deactivation to work you need to keep the valves closed on the deactivated cylinder. If you don't close the valves you increase the pumping losses of the engine. (You are essentially using that dead cylinder as an air compressor.) Pumping air also causes all kinds of problems with the engine management as noted by RedDevil

Originally Posted by oil pan 4

It only works in engines with hydraulic lifters.

Plenty of overhead cam engines have cylinder deactivation. They use two piece rocker arms with a pin connecting them. When the cylinder is in use oil pressure keeps the two pieces pinned together allowing the valve to open in close. When the cylinder is deactivated the pin is disconnected so the cam is not longer connected to the valve.

EDIT: Eaton's overhead cam cylinder deactivation
http://videos.eaton.com/detail/video...tion-with-lash

[Vman455]

Originally Posted by RedDevil

The vacuum will draw some oil into the cylinder head. Maybe it seeps back into the oil pan when the engine is at rest, otherwise the buildup may cause trouble.

That alone would stop me from trying this on a Prius, since the 2010s and 2011s are already known to be prone to developing oil-burning issues as they age.

[Fat Charlie]

My Fit lost an injector a year and a half ago. It was scary, I didn't think I'd make it up a couple hills no matter what gear I was in. Maybe it was the limp mode, but I don't want to see that again.

[D.O.G.]

Originally Posted by Fat Charlie

My Fit lost an injector a year and a half ago. It was scary, I didn't think I'd make it up a couple hills no matter what gear I was in.

One of my wife's previous cars (Holden Gemini from many years ago) snapped the camshaft in half so it only operated the valves on the front two cylinders.
It ran on the flat, but wouldn't go up hills. Living in the mountains as we do, it meant getting the car towed home.

[oldtamiyaphile]

My FIAT runs great on 2 cylinders. I have had it on one cylinder (coil pack failure) and it still went well enough.

[hayden55]

Originally Posted by Vman455

That alone would stop me from trying this on a Prius, since the 2010s and 2011s are already known to be prone to developing oil-burning issues as they age.

Yeah I'm not one to try it on the Prius. Car is too nice to be doing hanky mods. Makes me want wanna do a catch can but my car only burns like 1/2 to 3/4 quart over 10k. Considering what most of my American cars have used over 7.5k that's fantastic. 😂
What about your car? I mean on the worst end of the scale I went 12k on walmart syn and never had to add any oil. Still up halfway on the stick.