Correct me if I am wrong, but with no signal from the O2 sensors with the ECU not stay in open loop mode? Hard on the MPG I would think
Nope, assuming you weld/clamp those straight pipe sections so there are no exhaust leaks, then the front O2 sensors (ahead of the cats), still get the same data they always have. These front 2, "upstream", sensors are what the ecm uses to monitor and control a/f ratio and engine fueling. The second set, or "downstream" sensors, after the cats, serve only one purpose; to monitor the function of the cats. The ecm compares the reading between the upstream and downstream sensors, to determine what change the cats are having on the exhaust. At no time does the ecm use the downstream sensor data to actually control engine function/operation.
Yes, you'll get a CEL, w/ no cats, as the computer will see no change in the exhaust between the up and downstream sensors. The code will indicated catalyst failure or something similar. However, it will not put the computer in to a "limp" mode, and quite possibly INCREASE mpg, as the cats DO represent a restriction in the exhaust. PERIOD! It's is the truth, whether you green weenies like it or not. Neither "our" engines, or any other 4-stroke gasoline engine currently known to exist needs "back-pressure" , before you even try to make that claim. What an engine does need is as much flow as possible w/o compromising velocity. Basically, you need an exhaust system "just" big enough to do the job. Removing the cats does NOT cause the exhaust system to "feel" too big to the engine. Now, just hollowing out the cats, and leaving them in place DOES severely compromise exhaust flow velocity, and performance/mpg/drive-ability; as it creates an expansion chamber.
Now, if all of you whining fed-butt kissers would have actually read the op's posts, you'll notice, he said he wanted to do it TEMPORARILY, to get him by until the next paycheck, and that he NEEDED the vehicle to get to work.
Someone suggested he just "live with it" until he could fix it, to avoid breaking the law and "polluting". Others just jumped down his throat for even considering it,etc..... So you think he should keep driving it with a clogged cat, risking severe engine damage along the way; rather then break your precious almighty federal "law"? That's just ridiculous. Not to mention, driving it with cats that severely clogged, besides leading to severe engine damage, would likely cause very poor performance, and generate far more pollution than a good running engine w/ no cats. Or, maybe you think he should stay home and lose his job, rather then risk offending your delicate noses, and your own beliefs? Again, he said it was a temporary solution to an emergency situation. Survival, getting to work,etc... trumps the clean air act in my book, and in that of any reasonable, rational person.
As for those of you suggesting he shouldn't have bothered posting, knowing how YOU would respond; well maybe you shouldn't have bothered replying to his posts, knowing that you were just trying to bully him, and that your response was not one which answered his posted question.
The OP was NOT promoting anything. Again, not by any reasonable, rational definition of the word. He simply wanted to be reassured that he wouldn't damaging his vehicle by making a needed TEMPORARY repair, in order to get to work/live his life/etc.... "Promoting" would be more like posting: " Hey guys, do this. Its a great idea, and you should all run out an do it tomorrow. Hey let;s all get together on xx/xx/10, at place x.., and lets all celebrate all the illegal things we've done to our trucks. Yaaaayyyy illegal mods! " That would be "promoting". Not, asking if it's ok to do something to your tuck, to get to work, and not cause more damage to it in the process..
Seriously people, quit "promoting" YOUR beliefs/philosophies, by bullying and trying to "guilt" others. If you don't have anything nice, or helpful to say, in relations to the op's actual question/goal, then you just stay out of it.
As a side note, I wonder how many of the "follow the law, just because it's the law, always, without question,etc...." preachers have smoked a joint or something? You do know that is something that is also against federal law, even if your state "allows" it? Right? (FYI, just to be clear, I do NOT, Never have, and Never will use drugs of any kind. (not counting copious amounts of soda,coffee, and ice tea
), However, I don't care if you do it; just don't drive or anything.)
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