Tuning quiz....

[I Hate Import Cars]

So, someone asked me this, and I got it wrong, so I'm curious as to if anyone else will know. Here goes;

If you are tuning a motor, and are using a wideband O2 sensor to monitor it, and you pull off ONE spark plug wire, what will the sensor show? Will it go rich? Will it go lean? Why?

Please write your answer and an explaination as to what lead you to that conclusion. This was very interesting to me. Oh, and piss poor grammer and punctuation will not be tolerated. Thanks.

[AgentTed]

fuel is still spraying but not burning, but air is still present with o2 so I will guess lean.

[Wholesaler]

pull off the wire to the plug or have an open cylinder?

[B16offuryz]

x2 same question?? if they just pull the wire ...... will be a rich mixture since a/f is not being burned,.

if is an open cylinder...... its hard to say because a/f is being leak tru the spark plug hole

[I Hate Import Cars]

Read it again. "pull off one spark plug WIRE".

[AgentTed]

was i close?

[Type - O]

i would say rich since the mixture isnt burning. or maybe lean since the o2 sensor cant tell what a unburned mixture will be like or something to that affect

[KingDingaLing]

i say its gonna be the same as it was with 4 cylinders

[Wholesaler]

i say its gonna be the same as it was with 4 cylinders

thats what im going with, the amount of air and fuel entering the motor isnt changing

[efyoufool]

ima go with rich cuz ur dumping in gas into the cylinder and its not igniting at all.

[Lilrob]

neither lean nor rich

[Type - O]

is that your FINAL answer

[I Hate Import Cars]

How long should I let this go for? One person was pretty close so far...

[Lazieb29]

rich

[LiLinsane]

hmmm., I would say that it would show lean..

because the o2 sensor detects on the exhaust.

Oxygen should be depleted when it passes thru the sensor, if it sees an excess of oxygen it will assume that the engine didn't finish burning everything that it should, and normaly needs more fuel... its counting how much oxygen is left over after the combustion, if the combustion is compleate then there should not be any oxygen left in the exhaust.
but if somebody unplugged the spark plug, i would guess it would start seeing loads of extra O2.

which means:

Too much Oxygen = Fuel ratio is out of porportion, you have more air then gas, and you need more gas = lean
Not enough Oxygen = Have excess gas to burn in your mixture = rich

[I Hate Import Cars]

hmmm., I would say that it would show lean..

because the o2 sensor detects on the exhaust.

Oxygen should be depleted when it passes thru the sensor, if it sees an excess of oxygen it will assume that the engine didn't finish burning everything that it should, and normaly needs more fuel... its counting how much oxygen is left over after the combustion, if the combustion is compleate then there should not be any oxygen left in the exhaust.
but if somebody unplugged the spark plug, i would guess it would start seeing loads of extra O2.

which means:

Too much Oxygen = Fuel ratio is out of porportion, you have more air then gas, and you need more gas = lean
Not enough Oxygen = Have excess gas to burn in your mixture = rich



*DING* *DING* *DING*!!! We have a winner! "What do we have for him, Johnny?"

Very good. Even though there is no cumbustion taking place, it will not show rich, because it only knows how much oxygen is coming through the exhast. And when there are approx. 14 parts oxygen to every 1 part fuel to make a complete burn, (in which there is NO oxygen OR fuel left over), but the ecu sees oxygen left over, it follows logic that there was not enough fuel molecules to get rid of all of the oxygen, so it thinks it's lean. If it were rich, then all of the oxygen would have burned and there still would have been fuel molecules left over. It didn't make sense to me until it was explained to me that way. That was a fun one. Any thoughts?

[AgentTed]

so what was wrong with my answer?

[I Hate Import Cars]

so what was wrong with my answer?

Nothing. I told you someone was very close after you posted. I couldn't say it IMMEDIATELY after you posted. It was like the first response. I wasn't bored with the thread yet. You had it, just not much detail in the explaination. Are you really mad about it? Or are you mad because I didn't say DING DING DING to you? I bet that's it. I HATE when someone else get's a DING DING DING that I EARNED!