Catalytic Converter

[RonMar]

Yep, it is probably throwing an O2 code of some sort. As mentioned take it to an independent or even to schucks and read the codes yourself(they have readers you can use in their parking lot to read the fault codes). The plugin to connect the code reader is probably near your right knee when seated in the drivers seat.

It probably has two O2 sensors, one upstream of and one downstreeam of the catalyst. If it has two cats, the upstream O2 sensor is probably between the cats. I have never seen a code or sensor for a cat, but reading differences between the two O2 sensors can tell you what the cat is doing. Even if you dont have emissions testing requirements, simply removing the cat may not allow the two O2 sensors to read something they are happy with, and even with good upstream and downstream O2 sensors, you still may get a trouble code...

How old are the O2 sensors? If original, probably best to figure replacement sensors into your bill somewhere. As mentioned, 130K is a good long life for something that lives and breathes in the exhaust stream of an internal combustion engine

Good luck.

 

[WVBill]

As folks have said, and I can attest from recent experience, within a few months if this is your daily driver, the cat converter will get almost completely plugged up and will so restrict flow of exhaust that your call will not pull under load.

Something has caused your cat converter to fail. In my case, I ran my Pontiac Vibe 180,000 miles without a tune up (dumb me - but it always seemed to run fine). Eventually the spark plug gap got so wide that it was dumping un-burned fuel into the cat which caused it to fail. After replacing the cat, only then did it throw a check engine code that indicated running rich.

 

[N80]

That's the odd thing though. This car runs fine. Gas mileage is as good as it has ever been, maybe better. But, I need to do a few things. First, all of this info is second hand from the dealer via my wife. I need to talk to the dealer, although my wife says she has a written description and estimate that I need to look at. Second, I need to find someone else to do this work. This dealer is occasionally a little shady and always far more expensive than everyone else. Got the struts and axle seals done by a reputable guy for literally half the cost of the dealer. I think I need to get a second opinion from him since there is no obvious evidence that anything is impeding exhaust flow at this time.

 

[ray66v]

That's the odd thing though. This car runs fine.

It only takes an intermittent misfire on one plug. You can easily not notice it happening.

This could be from lots of things; a bad wire, bad coil, bad plug.

Did you do the metallic noise test I suggested?

 

[WVBill]

I had my dealer replace the cat on mine. He's very trustworthy. Price was $455 parts + Labor. I checked on-line and an after-market cat converter for my car ran around $375 so he was fair with me again.

My car ran fine too - until one day when it barely made it up the mountain I drive over each day (8% grade).

 

[N80]

It only takes an intermittent misfire on one plug. You can easily not notice it happening.

This could be from lots of things; a bad wire, bad coil, bad plug.

Did you do the metallic noise test I suggested?

Yes, I don't really hear much other than the typical cooling down noises it has always made.

So are you saying the cat could be damaged because of a recurrent misfire? I understand how that might happen but the diagnostics should indicate that as well I would think.

I'm getting a check engine light on my son's old Maxima and was told it was misfiring and they were able to tell which cylinder it was from the diagnostic. Of course they couldn't say if it was a plug, wire or coil. Anyway, if that was happening on the Murano I hope they could tell that too. Would hate to replace the cat and then have a continued misfire problem.

You know, I hate to sound like an old man, but I got well over 160k miles on my first Nissan pickup with a four banger a carb and a mechanical distributor. Never had a problem with it (until it was totalled). Not sure what we're gaining with these high tech engines. I'm pretty sure I know what the dealers are gaining with them.

 

[N80]

RonMar, do the O2 sensors provide any performance or durability benefit? I don't care if the check engine light stays on. What I'm getting at, is if I hollowed out or replaced the cat with a tube, will the abnormal readings from the O2 sensors cause any problems other than emissions problems and a check engine light?

 

[kenmac]

You can buy a cheap code reader for about 60-70 bucks @ most auto parts stores. It will tell you which cat is bad as in bank 1,2 etc, you can also clear the code & see how long it takes to come back on. The computer shouldn't be making any engine adjustments.So, it should be running just fine. Just letting you know the cat is bad.. Stay away from the high flow cats. My son had his factory cats taken off for high flow cats,. His sensors are now throwing bad cat codes.

 

[RobertN]

That is exactly what happened to me. Was four hours from home, going over Buckhorn Summit, and it seemed a little sluggish. Next day continued up the hill to Weaverville(North Calif), and barely rolled in to town. Literally, made the last half mile in granny low('89 Ford F250 with a 351).

My car ran fine too - until one day when it barely made it up the mountain I drive over each day (8% grade).

 

[dmccarty]

This is bringing back nightmares.....

My wifey bought a used Volvo. I think it was a 98 V70 station wagon...... I will skip the engine rebuild....

We have emissions inspections in NC. The Check Engine light came on in the car and the fun began. No way to pass with the light on. No passed inspection then you do not get a registration. :confused2:

We knew a GREAT Volvo mechanic. The Check Engine light would pop on because of the O2 sensors and the Cat. Somehow the mechanic got the car to work long enough to pass the emissions inspection but a couple of months later the Check Engine light was on again. This time we had to replace the Cat which we did with an after market unit for a fraction of the cost. The mechanic did say the Volvo units were better but given the age of the car we were not going to spend the dollars.

The old cat is sitting waiting to go to the junk yard. Course it has been waiting for a couple of years and I wonder when SWMBO will take it to the junk yard.

Later,
Dan