I hope they choke on the fumes...

August 26, 2008 1:48 AM

Should I get a new catalytic converter for my truck?

A few days ago, after having my Toyota Tacoma sitting for a few days, I started my truck. It sounded as if someone had ripped of my exhaust system. Undaunted and drunk, I got myself home. The next day I examined my exhaust system to, lo and behold, discovered someone had sawsall'd my catalytic converter out of my trucks exhaust system. My community has a lot of tweekers in it and a copious amount of metal theft, so I have a feeling someone is smoking the shit out of the $100 dollars they got out of it.

I'm poor, and really don't give a fuck about replacing the converter itself. All I want is my truck to not be as goddamned loud as it is now with a short exhaust system. I live in rural Washington state, Centralia specifically. Should I actually worry about replacing the converter itself, for the sake of my truck and my legality, or could I do with just welding in a piece of pipe to vent my exhaust and make my truck quite(er) again?

Again, I don't care about legality, I just want a quieter truck and a repair job where I don't have to worry about harming my engine.

posted by ZaneJ. to travel & transportation (5 comments total)

What are you asking exactly?

Do you want to know if your Tacoma will still run without the catalytic converter? A rudimentary google search says yes, but performance might be adversely affected since on newer vehicles there are oxygen sensors before and after the converter that determine the fuel/air ratio going into the engine. This might not apply if your truck is an older model.

Do you want the name and address of a mechanic who will weld in a length of pipe to bypass the place where the converter used to be? Sorry, that's not only illegal work for the mechanic to do, it also seems to be illegal for the mechanic to do any other work on a vehicle not fitted with the converter. Maybe one of the tweakers nearby with some car knowledge might do it for you if they haven't yet sold their welding equipment for meth.

Washington State appears to require an emissions test. You won't pass, and when you get pulled over for not having the right sticker, your missing converter will get you in even more trouble.

Finally, I am oh-so-impressed with your cavalier attitude towards drunk driving. Were you too drunk to look up this information yourself? It took me three minutes.
posted by cilantro at 4:12 AM on August 26, 2008 [1 favorite]

The obvious choice would be to first call the police to report the theft and then to call your insurance so you can get it replaced.
posted by JJ86 at 5:38 AM on August 26, 2008 [1 favorite]

I know this won't make you feel any better, but these thefts have taken a dramatic rise lately and trucks, especially 4wd ones, are prime targets as it is easy to slide underneath them. The thieves sell the converters for scrap (platinum).

You might see what you can find at a local junkyard.
posted by caddis at 7:40 AM on August 26, 2008

Having grown up in rural WA, cilantro, I can attest that being poor and drunk driving are kind of the official local sport. Doesn't make the submitter not an idiot, but if he's where I think he is it's a different kind of life... The interesting thing is that his truck had been sitting for a few days, he was drunk, then he drove home. Consider the series of events that implies.

Anyway, rural WA (when I lived there) didn't have emissions tests. It might now, but I don't know for sure. If it still doesn't, he's fine driving without the CC as far as emissions go.

However... Depending on the era of Tacoma - and if he's rural and poor it might not be a current generation - his issues could range anywhere from the computer throwing a CEL and trying to compensate to working just fine.

So to answer the submitter's question:
If it's an earlier Tacoma, weld a piece of straight pipe in place.
If it's a later Tacoma, weld a piece of straight pipe in place and get a signal conditioner for the O2 sensors.
Or take caddis' suggestion and fix it the right way by buying one from a scrap yard. With any luck you'll even get your original back and it'll slide right in, then just weld in place.
posted by krisak at 8:42 AM on August 26, 2008

Even on cars with three oxygen sensors the post cat sensor doesn't have a huge influence on the tuning of your engine. It'll set off the check engine light but it won't dangerously lean your engine (imagine the liability if the sensor failed and it fried your engine). In extreme cases you might run a bit rich which will reduce your gas mileage.

Welding in a straight pipe will allow your down stream muffler to do it's job. Your truck will be a mite bit louder than before as your cat had a muffling effect but it'll be orders of magnitude quieter than an open exhaust. If you want to get fancy you can even regain some of the difference by either welding in an S bend or using a significantly larger diameter piece of pipe for the patch (say 3" on 2.5).

And you are much more likely to get a ticket for an open exhaust than you are for having bypassed it. Afterall cops can hear an open exhaust, they have to get dirty (and already have you stopped) to ticket you for cutting out a cat.
posted by Mitheral at 11:30 AM on August 26, 2008