626 basic question-3 catalytic convertors?

[hafenbrack]

My sister owns a 1997 Mazda 626. Her engine light has been going on lately so she took the car to the dealership. They told her that the problem is the front "warmer catalytic convretor". They then proceeded to tell her that her car has 3 cat. convertors, 1 in front and 2 in back, I have NEVER heard of this b4 and and very curious about whether or not this is true? ANyone out there have an answer to this for me?

[Jpit]

No I believe that to be quite false. I have a '97 4 cylinder 626. My car has 1 pre-cat, 1 catalytic converter, and 1 resonator and one muffler. Your car has 2 Oxygen sensors. One is mounted right before the precat and the other is mounted abot 8 inches below it just after the pre-cat.You can see them if you open the hood and look straight down where your exhaust exits the engine.

The problem with our cars is that they should have mounted the second O2 sensor after the catalytic converter. They changed it on the '98 and did just that. Your mechanic is correct by THINKING the warm-up cat(pre-cat) could be your problem. My guess is that it isn't.

If you haven't had the O2 sensors replaced and you are nearing 100K miles now may be the time to replace them. Was the code that he read a P0421? I can bet you it is. If it is, it's generally the second O2 sensor that causes this. There is a TSB(technical Service Bulletin) that Mazda put out for this code. You may want to ask them about it. O2 sensors replaced by the dealer can be expensive but check your warranty. Emmisions parts are warranteed a lot longer than the rest of your car.

By the way if you want to find out the code and you have an Autozone Auto parts store near you they will read her code out for FREE! May be worth a shot the next time it comes on. Also another note. You can reset the code yourself by disconnecting the battery's negative terminal for a few minutes and re-connecting. She will have to reset her preset radio stations and the car may not feel like it runs properly for the first 40 miles until the computer has re-learned it's sensor inputs.

If you are slightly mechanicaly inclined yourself, you can replac your O2 sensors in about 15 minutes. You need to have a 22mm slotted socket to remove it, just disconnect the connector(press on a tab to release it). Repeat for the second O2 sensor. You will save her a lot of money. You can buy the sensors at many places. I bought mine at www.oxygensensors.com.

[hafenbrack]

I wish I had known that before. She let the mechanic fix the problem without a second opinion. She did ask al ot of questions, but yo uknow how they can be, we know whats wrong this is what needs to be done. Well this was the dealership and I will find out exaclty what code that was given when they ran their tests. If I find totu that they replaced something that didn't need to be replaced because of a lack of interest in finding the reall problem then they shall be reimbursing her $900. Thank you so much for your response, I will make good use of your information.

Originally Posted by Jpit

No I believe that to be quite false. I have a '97 4 cylinder 626. My car has 1 pre-cat, 1 catalytic converter, and 1 resonator and one muffler. Your car has 2 Oxygen sensors. One is mounted right before the precat and the other is mounted abot 8 inches below it just after the pre-cat.You can see them if you open the hood and look straight down where your exhaust exits the engine.

The problem with our cars is that they should have mounted the second O2 sensor after the catalytic converter. They changed it on the '98 and did just that. Your mechanic is correct by THINKING the warm-up cat(pre-cat) could be your problem. My guess is that it isn't.

If you haven't had the O2 sensors replaced and you are nearing 100K miles now may be the time to replace them. Was the code that he read a P0421? I can bet you it is. If it is, it's generally the second O2 sensor that causes this. There is a TSB(technical Service Bulletin) that Mazda put out for this code. You may want to ask them about it. O2 sensors replaced by the dealer can be expensive but check your warranty. Emmisions parts are warranteed a lot longer than the rest of your car.

By the way if you want to find out the code and you have an Autozone Auto parts store near you they will read her code out for FREE! May be worth a shot the next time it comes on. Also another note. You can reset the code yourself by disconnecting the battery's negative terminal for a few minutes and re-connecting. She will have to reset her preset radio stations and the car may not feel like it runs properly for the first 40 miles until the computer has re-learned it's sensor inputs.

If you are slightly mechanicaly inclined yourself, you can replac your O2 sensors in about 15 minutes. You need to have a 22mm slotted socket to remove it, just disconnect the connector(press on a tab to release it). Repeat for the second O2 sensor. You will save her a lot of money. You can buy the sensors at many places. I bought mine at www.oxygensensors.com.

[Jpit]

Too bad to hear that. I guess after that much money it better be fixed. Sounds like they replaced most of her exhaust system including the O2 sensors. That'll fix it....

[kennyc28]

The rear o2 sensor is about 300.00 I just bought a universal one for 135.00 and just soldered the wires together and it worked just fine. Yeah they tried to tell me they wanted 500.00 to replace the front sensor. I bought a universal for 85.00 and the 02 socket for 10.00 so it cost me 100.00 and I did it myself in 20 minutes. You must reset the computer after installing anything new just disconnect your negative cable and open the door and press the brake for 30 seconds then reconnect and your done. Its that simple

[slicebogeys madza]

When I press the gas pedal I smell eggs and my engine light stays on. I think I have California emissions is there a place to find a catalytic convertor cheap?

thanks in advance

[Jpit]

Originally Posted by slicebogeys madza

When I press the gas pedal I smell eggs and my engine light stays on. I think I have California emissions is there a place to find a catalytic convertor cheap?

thanks in advance

You should find out what the code you are getting first. Could be something else causing the high emmissions. And like you say it could be the converter also. On the '97 there is a warm-up catalytic converter(sometimes known as the pre-cat) and there is a main catalytic converter.

I believe California emmissions only allows the manufacturer's catalytic converter installed. Not sure if there are any after-market California cats available.

There are numerous places that carry the non-California cats if you type in "catalytic converter" on any search engine you will find dozens, all much, much cheaper than the dealer.