Try your knowledge

[blacksnapon]

If you have a misfiring spark plug, will your o2 sensors show rich, or lean?

 

[6L PWR]

If you have a misfiring spark plug, will your o2 sensors show rich, or lean?

I guess rich. Since it wouldn't be burning fuel. ???

 

[surewhynot]

Thats my guess too.

 

[slmann]

that's what I went with too. but I'm just guessing.

good post Vince. You gonna school all of us here?

 

[blacksnapon]

that's what I went with too. but I'm just guessing.

good post Vince. You gonna school all of us here?

I just want to hear all of the gears turning! There's a lot of these examples out there that are maddening!

 

[Blue Goose]

I'm one of those lean votes.

 

[O'Rattlecan]

I voted rich. If it's not firing, then fuel isn't getting burnt. Which Oxy sensor? HEGO?

Ryan

 

[blacksnapon]

I voted rich. If it's not firing, then fuel isn't getting burnt. Which Oxy sensor? HEGO?

Ryan

any of them

 

[mrfixit]

I voted lean. computers these days sense the misfire and turn off the injector, but the cylinder is still pumping air. 02 senser has a certain volume of air passing that would show lean because of the dead cylinder.
Even my old van ran pretty good with one plug wire off!

 

[CaFordDude]

I voted rich but I don't have any knowledge to back up that guess. I'm just playin the game...

 

[mrxlh]

Rich, still getting fuel, and not burning it. (unless the injector is disabled by the mis-fire code, which in that case it would lean it out) Depending on how loaded the engine is, it will also show detonation and a lower % level of free oxygen in the exhaust as read by the O2 sensor nearest the cat. So when do we get the answer Vince?

 

[Bob Ayers]

I voted lean due to the O2 being dumped into the exhaust from the misfire.

 

[Fellro]

I would say it depends, not enough info. If it is the fault of the plug/wire that it is misfiring, rich. If it is the fault of fuel supply or other issue, lean. Also, if the misfire is due to a mechanical problem, it can go lean or rich.

 

[blacksnapon]

OK, I kind of think this one is going as far as it will ever go! LEAN---the reason, O2 sensors measure oxygen, not fuel. Oxygen is consumed during combustion, no spark, no combustion, excess oxygen in the exhaust flow.

 

[mrfixit]

I think it will always read LEAN in rattlecan's truck; He's so broke he even makes the truck starve!

 

[O'Rattlecan]

Don't go runnin that car around with gasoline! That'll burn it up!

Ryan