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Showing results for tags 'catalytic'.
Found 4 results
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While I was admiring the underside of my bran new 19 Silverado I noticed the exhaust pipe, immediately after the cat, is squished, like super flat... Has anyone replaced that section with a normal round piece of tubing? Did it make any improvements in sound/mpg? Seems like it must!
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Hi guys, I have a 2003 Silverado 4x4 with a 4.8 and 3.73s and auto trans. My catalytic converters were very plugged up and I ended up cutting them open, removing all of the material inside, and welding them back together. The truck has run much better since doing this. The problem is, since doing this i have been getting about 13.8-14 mpg with it. This is driving the same route i had been getting 16-17mpg previously. I am thinking that this has something to do with the fact that i left the o2 sensors in place. I am looking for a relatively inexpensive fix/ improvement for this, because this is just a rusted out daily driver truck with 160k that I don't really want to put a ton of money into. I wanted to see if anyone had any experience with this before I tried a few of my ideas. Any advice would be appreciated. Also, i am aware that this is technically illegal, but there are no emissions tests in my state, so running no cats is not a huge issue for me. thanks
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Okay, Algore and company please leave the thread now and tune in to the most recent global warming propaganda station, as offensive stuff will follow. If you have a problem with your cat converters clogging, and you end up gutting them (even temporarily to avoid engine damage), you may note some horrible gas mileage. My truck... a 1996 K3500, 4 door, 8 foot bed, with 5.7 Vortec engine, 4L80e transmission. My mileage went to 7.5 mph (yes, literally) after opening converters. I had been getting 11 to 12 mpg. Fuel was so rich it would fog you out sitting at the drive thru. :o I got lots of advice from various folks, up to and including that I needed to just "bite the bullet" and replace both cats and o2's or the truck would never get correct fuel mileage. And the guy with the spinner in his ball cap of course points out that opening up the converters is ILLEGAL. (he likes to put that in all caps)... And his name is Ogilvie, regardless of what his forum handle happens to be. But a GM tech who is a friend of mine told me to unplug the rear 2 oxygen sensors and see what happened. That in fact worked *perfectly*... my truck began to run like it used to, and mileage went back to 11 to 12 mph. I do realize there is a way to use anti-fouling spark plug spacers to offset the 02's in the front (maybe?) to create a temperature difference, and get rid of the check engine light. But my front 02's after 22 years don't want to budge. I post this just in case it may help someone out there with the same problem. Dan -
I am brand new to posting on forums, but I have used much info from them. I have a 2003 Yukon XL with 126,000 that I bought recently. It had been sitting for 3+ years. It had NO power and could barely climb the slightest grade. It started and idled fine. The check engine light was on and it had 2 codes, random misfire and mass airflow sensor out of range. I decided to replace the MAF and it had no affect. Since it has 2 separate cats, truck still ran ok at idle Here are the specs before repair: fuel pressure - 45psi - Increases if i remove the regulator vacuum line Vacuum at idle - 14 - 15 inhg fluctuating. replaced: air filter MAF MAP Fuel filter Plugs Wires All with no affect. Pulling off the coil pack leads one at a time, the pass side seemed to have less affect than the drivers side. Threw in the towel and limped it to my local garage. They confirmed that that it was a clogged catalytic converter on the passenger side. I replaced it, and now all seems fine. It is not as obvious with 2 cats as it is with one. I'm not sure if the sitting around corroded the cat or the fact that they would start up and idle the truck for long periods during it's storage. Just thought this info would be useful to some else. Now I get to find out what else is wrong......
