Thorley Header Install

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Jun 15, 2010 | 09:58 PM

#31

Johnny Langton

Postmaster

Joined: Oct 2006

Posts: 4,171

Likes: 12

From: SE Texas

Quote:

Originally Posted by HB76

Ok smart one tell me just how does the eecu know which cylinders its reading the exh from... If you want a true closed loop you would need a sensor on each cylinder...
That ain't going to happen. Plus each injector isn't adjusted to the oxy sensor each time it fires... You are giving them way to much credit. Its just a half *** closed loop system, it could care less how many cylinders its testing.
Plus if its testing 5 cylinders and 4 are ok the other one would have to be way off to over ride what the others are putting out... Or two could be way on the lean side and two just right so that would mean one could be way rich and still be in specks....
Just something for you desk top mechanics to think about before you come out to the real world...

The PCM knows how much O2 should be in the exhaust stream at a given air/fuel ratio,and knows if a single cylinder is lean/rich based on when that cylinder's spark plug fires and the transport delay from the spark plug being fired til the exhaust should be at the O2 sensor. It gets far more complicated than that,but it should suffice to say that the PCM can control air/fuel of a single cylinder based on O2 input,so accurate measurements of the O2 in the exhaust are vital for a properly running engine that will operate at peak efficiency.
JL

Jun 16, 2010 | 07:10 AM

#32

krewat

FTE Leadership Emeritus

Joined: Jul 2002

Posts: 42,561

Likes: 423

From: Long Island USA

Not to mention that 3 cylinders are never going to provide an even stream of exhaust - dead spots occur, and what does the PCM see at the O2 sensor?

Jun 16, 2010 | 07:11 AM

#33

krewat

FTE Leadership Emeritus

Joined: Jul 2002

Posts: 42,561

Likes: 423

From: Long Island USA

Quote:

Originally Posted by HB76

Just something for you desk top mechanics to think about before you come out to the real world...

If you think JL (or anyone else here) are "desktop mechanics" you haven't been here very long, have you?

Aug 24, 2010 | 01:13 PM

#34

fomoco6.8

Freshman User

Joined: Nov 2009

Posts: 45

Likes: 2

From: Southern Maine

Ex03AK..... Hi Stew, check your PM's. Thanks

Mike

Aug 24, 2010 | 10:34 PM

#35

Pinky Demon

Posting Guru

Joined: Dec 2007

Posts: 1,361

Likes: 0

Quote:

Originally Posted by HB76

I have the same setup, and I'm not worried about the closed loop being off because of not catching a sniff of every cylinder. It wont know which ones its checking anyway... Only time it would make a big deal is if a injector or plug went bad, then you'd hear a miss anyway.
Carburetors worked just fine for years till EPA got their noses into everything... And we don't have no smog sniffers around here to check on us anyway

And know we all know to disregard everything you post after this. Thanks for the heads up.