Gregor 4,846 #1 Posted August 2, 2021 My grandsons car has a warning light on. It is a 2012, Ford Focus. Sorry, that's all I know about it. The code indicates the catalytic converter. If possible, I would like to simply eliminate it. What are the ramifications of doing this. Illinois has no vehicle inspection. Will it cause any damage? Share this post Link to post Share on other sites
Jeff-C175 7,202 #2 Posted August 2, 2021 (edited) Illegal as far as I know. http://foryousolution.blogspot.com/2014/04/illinois-catalytic-converter-laws.html I don't believe it would cause any damage, other than to the environment. If your car has a 'downstream' O2 sensor, it will still probably continue to report a bad cat con. What code is it throwing? It's possible, I believe, that a bad O2 sensor could also throw this code. Edited August 2, 2021 by Jeff-C175 Share this post Link to post Share on other sites
Gregor 4,846 #3 Posted August 2, 2021 Yeah, I knew that, but sometimes ya just gotta do what ya just gotta do. 1 1 Share this post Link to post Share on other sites
Jeff-C175 7,202 #4 Posted August 2, 2021 3 minutes ago, Gregor said: Yeah, I knew that, but sometimes ya just gotta do what ya just gotta do. Is it a $$ thing? That's the only reason I could think of for not simply replacing the converter. If you DO replace it, be aware that a 'dead' converter can bring about $100 in scrap value at a recycler. Some even more... I think some shops build this scrap value into their replacement pricing, so if you tell them you want the old converter back they will charge you more. Share this post Link to post Share on other sites
Gregor 4,846 #5 Posted August 2, 2021 I had one go bad on the interstate once, truck simply stopped. I don't want that to happen. Share this post Link to post Share on other sites
Jeff-C175 7,202 #6 Posted August 2, 2021 3 minutes ago, Gregor said: I had one go bad on the interstate once, truck simply stopped. I don't want that to happen. Probably got plugged up I would guess. If the OBDII systems have something in place that kills the engine when the cat goes bad, that's news to me, and probably not a safe thing to do anyway. Share this post Link to post Share on other sites
Gregor 4,846 #7 Posted August 2, 2021 4 minutes ago, Jeff-C175 said: Is it a $$ thing? Yes it is. Share this post Link to post Share on other sites
Gregor 4,846 #8 Posted August 2, 2021 1 minute ago, Jeff-C175 said: If the OBDII systems have something in place that kills the engine when the cat goes bad, that's news to me, Something in my cat let loose, and simply plugged it. Exhaust could not escape. Won't run that way. Share this post Link to post Share on other sites
Jeff-C175 7,202 #9 Posted August 2, 2021 5 minutes ago, Gregor said: Yes it is. https://www.rockauto.com/en/moreinfo.php?pk=7270556&cc=1501060&pt=5808&jsn=450 Share this post Link to post Share on other sites
Jeff-C175 7,202 #10 Posted August 2, 2021 4 minutes ago, Gregor said: Something in my cat let loose, and simply plugged it. Exhaust could not escape. Won't run that way. What I thought. But that's actually a pretty rare situation when compared to the sheer number of cats that never get plugged. Share this post Link to post Share on other sites
Gregor 4,846 #11 Posted August 2, 2021 hmmm much less than I thought. Just now, Jeff-C175 said: What I thought. But that's actually a pretty rare situation when compared to the sheer number of cats that never get plugged. That's the way my luck usually runs. 1 Share this post Link to post Share on other sites
Jeff-C175 7,202 #12 Posted August 2, 2021 2 minutes ago, Gregor said: hmmm much less than I thought. That's the way my luck usually runs. Mine luck too! That's the least expensive they carry, they go up from there to almost $400. When you figure that if you do it yourself, and recycle the old one, it comes down to less than a hundred or so. 1 Share this post Link to post Share on other sites
Jeff-C175 7,202 #13 Posted August 2, 2021 (edited) 15 minutes ago, Gregor said: hmmm much less than I thought. I'm looking closer at the RockAuto replacements... I think your Focus might have TWO converters. Either that, or there are two different types used. It appears that there may be one built right into the exhaust manifold, and then one down stream but I am not certain. The higher priced ones include the manifold, flex pipe, etc... take a look and you'll see what I mean. They have pictures. The one that I posted looks like it is the downstream converter. Edited August 2, 2021 by Jeff-C175 Share this post Link to post Share on other sites
Gregor 4,846 #14 Posted August 2, 2021 Just watched a video. May have to re-think this. 1 Share this post Link to post Share on other sites
ebinmaine 67,605 #15 Posted August 2, 2021 Notwithstanding the above mentioned Federal illegalities of this.. Removing a catalytic converter can potentially cause two different issues I can think of just off the top of my head. One. The downstream oxygen sensor can't get a post burn reading because there is NO post burn. Two. Removing the airflow restriction that is caused by the catalytic converter from the factory preset fuel intake parameters could wreak havoc on the inlet side of the engine as well. Either one of those two things could potentially cause you vast volumes more than simply replacing a converter that IS BAD. Now take note of the fact that I highlighted the last couple of words there. I'm sure you're well aware of, but I'm going to remind you, it is absolutely necessary to do a proper diagnosis and figure out WHICH PART IS ACTUALLY BAD. It is legitimately possible that you have another component in the emissions or injection system that is causing a faulty reading. 1 Share this post Link to post Share on other sites
Jeff-C175 7,202 #16 Posted August 2, 2021 3 minutes ago, ebinmaine said: It is legitimately possible that you have another component in the emissions or injection system that is causing a faulty reading. Exactly. For example the 'downstream O2 sensor'. If it is bad it could make the ECU think that the cat is bad. That's why I wanted to know the exact code that it threw. Share this post Link to post Share on other sites
Gregor 4,846 #17 Posted August 2, 2021 1 minute ago, Jeff-C175 said: That's why I wanted to know the exact code that it threw. Off to yet another Dr, Appt. Later Share this post Link to post Share on other sites
pacer 3,173 #18 Posted August 2, 2021 My grandson gets his first car (Subaru) after he got a pretty decent job ..... typical teen he wanted to start adding after market 'enhancements'. One of these was a kit to remove the existing exhaust and replace it with a cat free system -- this was along with several other 'add-ons'. After several months and no telling how much money he gave up, and decided to bring in professionals to diagnose, he was told that along with other factors the main problem was no cat and the computer just wouldnt accept that ... it would run, but badly, so he finally listened to Dad and sold it for parts I have been told several times of incidents where the cat/s were removed to add dual exhaust - (like many of us wanted to do when that was possible) - and the car/truck would just run like crap, the computers just wont accept it. I personally love the sound of a good dual exhaust and down thru the years have had many a ... vehicle? that I added them to, but sadly no longer can do. Share this post Link to post Share on other sites
Zeek 2,286 #19 Posted August 2, 2021 (edited) I saw that mentioned watching a video. If you search YouTube "catalytic converter vs no catalytic converter hp" you may find that there is likely not much of an advantage in a street car to eliminate the converter. That is probably more so the case with a car that new. It may have been an advantage back in the 80's with the original beginning converter technology, but things have come a long way since then. I'd change the muffler if he want's to make it sound better than stock. Just my 2¢ as an old motorhead Edited August 2, 2021 by Zeek 1 Share this post Link to post Share on other sites
pacer 3,173 #20 Posted August 2, 2021 16 minutes ago, Zeek said: I'd change the muffler if he want's to make it sound better than stock Thats what I did on my '06 150, felt just a bit silly adding a Flowmaster and duals from there back .... but, surprisingly I did get a pretty decent sound from it. Course thats not what @Gregor is after..... 1 Share this post Link to post Share on other sites
squonk 41,153 #21 Posted August 2, 2021 Without the proper O2 signal the car will probably run like crap. This ain't 1980! 3 Share this post Link to post Share on other sites
ri702bill 8,334 #22 Posted August 2, 2021 All: All: We do a fair amount of backyard shade tree mechanic work here, and I find that the failed Converter is usually the victim, not the problem - but not always the case. I inherited a 1994 Saturn SL1 5 speed from my son in 1995 when he moved out of state. The previous owners son had done a stint of accidental offroading with it, and had flattened the bottom of the converter. Fast forward about a month and I hear a rattle in the exhaust and the car has absolutely no power. I let it warm up at idle and check the temp of the centerpipe with my HF infrared thermometer. Sure enough at the first 90 degree bend after the converter the rest of the pipe is cold. A good sized chunk of the honeycomb gotten wedged in that corner, blocking the exhaust. Ramrodded the pipe, replaced the converter, good as new ..... Bill Share this post Link to post Share on other sites
Achto 27,602 #23 Posted August 2, 2021 (edited) 46 minutes ago, squonk said: Without the proper O2 signal the car will probably run like crap. This ain't 1980! 5 hours ago, Gregor said: I would like to simply eliminate it. If you have a closed loop system with pre and post CAT O2 sensors then you will need one of the items in the link below to eliminate the CAT. It is a mini CAT that is installed in front of the post O2 sensor. This will solve your running/tuning issues as your ECU will think that the CAT is still in place. https://www.ebay.com/itm/233904036612?chn=ps&_trkparms=ispr%3D1&amdata=enc%3A1xK8UQvAsR829YIZQE0KE2w93&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=233904036612&targetid=1262376589376&device=c&mktype=pla&googleloc=9018822&poi=&campaignid=12873834640&mkgroupid=120270032814&rlsatarget=aud-622027676548:pla-1262376589376&abcId=9300536&merchantid=6296724&gclid=EAIaIQobChMI9M7IzfOS8gIVw25vBB28jg7DEAQYASABEgKVZPD_BwE Edited August 2, 2021 by Achto 1 1 Share this post Link to post Share on other sites
Jeff-C175 7,202 #24 Posted August 2, 2021 37 minutes ago, Achto said: mini CAT Well ain't that a clever little gadget! 1 Share this post Link to post Share on other sites
Achto 27,602 #25 Posted August 2, 2021 1 minute ago, Jeff-C175 said: Well ain't that a clever little gadget! Hot rodders always find a way around. 1 2 Share this post Link to post Share on other sites