Got a CEL today

[RX7-2nr]

hmm im gonna try Seafoam on my car. my car runs rough, idles rough, stalls, surges, and many more assorted probs.

[Titus]

There are two O2 sensors on OBD2 cars. One in front of the cat takes a reading and helps determine the fuel mixture. The second takes a reading and makes sure that there is enough difference from the first reading to make sure the cat is working. If the cat is new this most likely the issue. There are two kinds of replacements. OEM and generic. Both work the same, the difference is in installation. OEM has the OEM plug that takes about 15 minutes to replace from jacking the car up to back down again. THe other is going to require some soldering. For the price difference I would do the generic bosch. I think it is 75 while the OEM is around 2 bills.

To add to this, it is interesting to note that the cheap universal Bosch sensor does have a plug on the end, it just doesn't match the plug on the car. The plug does match several late 80's early 90's American cars. If you search miata.net, you will find a list of cars. Many go grab a few of the plugs off cars from the junkyard, and then cut the miata plug off of the old OEM O2. You can then wire up the plug from the bad sensor in your car to the junkyard plug that matches the universal sensor to make an adapter. You then have plug and play for OEM and Universal next time you need to swap one. Seems like a lot of work to me, but if you are already going to the junkyard for something, it might be worth while.

[Sharpie]

To add to this, it is interesting to note that the cheap universal Bosch sensor does have a plug on the end, it just doesn't match the plug on the car. The plug does match several late 80's early 90's American cars. If you search miata.net, you will find a list of cars. Many go grab a few of the plugs off cars from the junkyard, and then cut the miata plug off of the old OEM O2. You can then wire up the plug from the bad sensor in your car to the junkyard plug that matches the universal sensor to make an adapter. You then have plug and play for OEM and Universal next time you need to swap one. Seems like a lot of work to me, but if you are already going to the junkyard for something, it might be worth while.

I did that for mine when I did the new o2 sensor for the FM2. It came off a late 80's mopar sedan.

I've helped a guy replace both, crimping and connecting wires, not fun under the car. Try the Seafoam, it worked for Samm.

[riverracer]

Thanks for al the input guys. The plan is to do the Seafoam next Saturday morning. This weekend is booked for me.
Jerry

[Billy Blaze]

Hey Jerry if you do it on a Sunday I will meet up with you and help you.

[pliablemoose]

If the Seafoam brings my wife back I'd just as soon drive with the CEL on.......

LOL, guess I'm not gonna use seafoam after all either

[POS Racing]

Well riverracer other that blowin a lot of smoke today any thing chage???

[riverracer]

Well riverracer other that blowin a lot of smoke today any thing chage???

No not yet...I drove it hard at highway speeds for about thirty minutes after we finished. Light was still on.....So I came home and let it cool...then disconnected the battery and I have driven it 3 times since then and the light is still out...I'm going to drive it alot this week and keep you posted...Thanks again for the help

[riverracer]

Ok guys...here's the latest on my P0420 code problem....The light still comes on. Looks like the intake will have to be cracked...

[pliablemoose]

http://www.obd-codes.com/trouble_cod...old-bank-1.php

[riverracer]

http://www.obd-codes.com/trouble_cod...old-bank-1.php

Thanks for the link....
Ok guys what would you do first?

[pliablemoose]

Next step is to measure the voltage at the oxygen sensor on Bank 1 (the rear sensor, or the sensor after the converter). The voltage should be low and steady (~200mV, depends on the vehicle). If the voltage varies (e.g. 100mV to 600mV) then it's time to replace the catalytic converter. In fact, it would be a good idea to test each oxygen O2 sensor while you're at it.

Looks like that's the next step, the one after that looks pretty expensive