Here’s the latest reader question, along with my reply!
Todd asks: I read your recent article about people having the catalytic convertors cut off their cars by thieves. I’ve had the same happen to me and am reluctant to spend the money on a new converter because what’s to stop another thief from stealing, it too? But my question for you is – will running the car without a catalytic converter negatively affect anything?
My reply: Well, it will trigger the yellow “check engine” light in the dashboard to come on – and stay on – which is only a problem if you need to get a state safety or emissions test to renew your vehicle’s registration. And if that’s the case, the inspector is going to notice the absent cat, regardless. But there’s no negative effect of the light being on. Unless it just annoys you.
The car will be louder – because the cat has a muffling function as well an emissions function. This may or may not be a concern for you.
It may run better – and might get better gas mileage – because the cat is restrictive to the free flow of exhaust; an older/high-miles cat will be more restrictive due to the accumulation of carbon on the lattice/honeycomb surfaces within the cat. But it may also run worse, if there’s not enough backpressure; or because the computer alters the A/F ratio and so on because of the signals it’s getting indicating the cat is gone.
Some people get around some of this by wiring a resistor of the right value into the oxygen sensor circuit; this “fools” the computer into thinking the car’s cat is intact and operational.
You should be able to tell us more about what actually happens – after you run around for a few weeks, sans cat. Please keep us posted!
. . .
If you like what you’ve found here please consider supporting EPautos.
PS: Get an EPautos magnet or sticker or coaster in return for a $20 or more one-time donation or a $10 or more monthly recurring donation. (Please be sure to tell us you want a magnet or sticker or coaster – and also, provide an address, so we know where to mail the thing!)