Hi. I have Prius '01 with high millage 206K I have few problems with it. Check emgine light was on, we changed few things Oxygen sensor, Temperature sensor, thermostat and some sensor which made system tuline failure. It wasn't very expenssive, so I did all changes. I trust my mechanic, so if he said it was broken I think it is. He also showed me there is catalyic converyer failure code, but reconend me to forgot about it because of high price of cat. Told me ot will be more than 700$ for part. I want to to read your opinions about my case. I start change all those parts bevause my mpg go down. I drive 90% time thru the highways, most time at night (no traffic), everyday I keep my engine on when I'm sitting in a car and wait for at least 1,5 hour with heat on. It's winter time (10-35 F), my driving isn't too economy (I'm always in hurry) My MPG is now 31. What do you think, is it a reason of cat failure or is it normal? What other reasons of high gas consumpion can be? What do you think about cheap ($80-$120) aftermarket cat which is available at ebay? I hope someone will give me some answers for my questions. Thanks
Any particular reason why all those things were changed? What were the DTCes when you had the problems? The cold weather along w/sitting for 1.5 hours w/the heat on in the car is helping kill your mileage. That's 1.5 hours of 0 mpg. If you need further fuel economy help, please answer the questions at http://priuschat.com/forums/gen-ii-...-answer-these-questions-esp-if-youre-new.html
If you stop sitting in the car for 1.5 hours each day with the heat running, you'll see your mpg's improve quite a bit. Any reason why you do that? Job? As for the cat converter, your mileage may improve if you fix/replace it. Doesn't it provide sensor feedback to car computer to determine proper fuel/air mix ratio or something like that? An improperly functioning cat converter will also have your car spewing higher pollution, if that's a concern to you.
If you drive in a non-economical manner and also are sitting around 1-1/2 hours a day in the Chicago winter with the heater running (which forces the gasoline engine to run) then 31 mpg seems reasonable. The Classic catalytic converter also includes an unusual hydrocarbon absorption chamber. Therefore if you wish to install an aftermarket cc, you will need to cut off the original cc and weld in the replacement. I recommend that you consult with your local muffler shop to ensure that the correct replacement is ordered. A failed catalytic converter has nothing to do with worsened mpg. The first oxygen sensor which determines air/fuel ratio is located upstream from the cc. It is anti-social to drive a car with a failed cc since the car is emitting more air pollution than necessary, but that's off-topic.
I suppose that the long 'sits' could contribute to catalytic converter failure, but yours (with 206k miles) has not failed early. An aftermarket cat will not provide that early-stage absorption of hydrocarbons. That is the trick of the OEM absorber. In more recent models Prius has used two different tricks for early-stage HC absorption, but they are still doing it. If we were voting here, I'd go with the original expensive replacement. The aftermarkets cost much less, but I guess their lifespan will also be shorter.
Aftermarket CAT's are a gamble. The so called "universal" CAT's don't necessarily fit and are not guaranteed to work in a specific application. It is Illegal in the US to sell used Cat's (unless you can test and certify them to original spec's. which is prohibitively expensive). Although, I am sure some folks do sell them. Its a federal rap. This is one case where a new OEM part is really the best option if you really do need a CAT. Eric
marchin, have you been able to improved your MPG yet? My granddaughter has a 2001 Prius with high mileage and she's only getting 32 to 34 MPG at most. I'd like to hear what you did if you've been able to improve your MPG up from 31. Thanks
If your granddaughter really wants mileage help, she should fill out the questionnaire I pointed to in post #2. 32-34 mpg might be all she can reasonably achieve given her commutes, trip lengths, tires, and weather conditions. See Toyota Prius: Consumer Reports for what CR got.
