Does anybody else have this problem? If so what is the issue?

 

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The same thing happened to me but it went away after approx 10 starts

 

Same here too as HalfAmazing. It eventually goes off. However, since I installed a new RSC exhaust it has not come back on.

Adam

 

I have Quicksilver exhaust... Hopefully it will go off!

 

turned out to just be o2 sensors for me - the ones fore of the cats

additionally - it also fixed a weak-start issue (lumpy low-idle starts)

 

beat the topic to death~~~

I'd say 90% of the time its the O2 sensor, $500-ish job from a dealer, much cheaper with a friend or DIY. Seems to come and go, but if you live in a state that plugs your car up for annual inspection, then it'll haunt you.

I was told my other sensor is failing soon by the dealer, sigh...

Good luck.

 

Is it covered under warranty?

 

I don't know about the 3 year warranty, mine just expired.

As for the longer 8 year Federal Emissions Warranty, AMLI said it's not covered. (read the book again myself, seems like they're right...)

 

My car still has the original manufacturer warranty so hopefully its covered...If not oh well

 

Seems like O2 sensors are a pretty common failure on the V8, and frankly don't last very long. If it was a product I felt we could source and improve upon we'd look into it but I have my theories about why they fail. I have seen a lot of OE cats with heat rings/discoloration and I have a sneaking suspicion that the O2 sensors are failing because there's too much heat build up in the catalysts...


That's the only picture I have to illustrate, but look at the heat ring around where the Lambda boss is. Just a thought anyway... could be completely wrong.

 

I was told by AM Long Island that the O2 sensors are failing because these cars "get too hot". So are you saying that it's the OEM cats that are causing this issue?

 

I'm not really sure, not with any degree of certainty anyway. However, the O2 sensors are definitely failing prematurely, so there is either some fundamental design flaw, or there's a huge batch of duff O2 sensors out there. Apart from old age, there really isn't that much which should destroy an O2 sensor apart from excessive heat. The reason I suspect the catalysts is because they seem to produce the heat rings like you can see in the above photo. Think about all the hot air trying to force its way through a very restricitve part - all that friction is going to generate much more heat than if the resistance wasn't there. So my thought is that the catalyst just isn't up to the task and it is generating too much heat and killing the sensors. The other possible contributing factor is that we know these cars tend to run rich on standard mapping. If there's a reasonable amount of unburnt fuel coming out of the engine that's going to ingnite in the manifold, or more than likely, the catalyst, which would definitely cook O2 sensors...

Again, this is far from being a peer reviewed Scientific study, just me thinking out loud and trying to explain the high failure rates.

 

I guess it's time to start setting aside some money to move away from the OEM cat. To have the car a bit louder won't hurt either. Maybe I'll put it in when I take the car in for the 30k service.

 

I just want to make sure I don't come across to badly. Obviously I'm biased so I should state that for the record, and this is just a theory I have. I also think that moving the Lambda bosses away from the matrix which gets the hottest and into the cone should help. But you have to figure out what the priority is, because you could buy 4 or 5 new sensors for the price of a set of cats, and whether replacing them with aftermarket units may or may not be a fix.

If you want some 200 cell cats and this is a good plus point for going for them then that's a different story!!!

 

Hi Stuart,

Thanks for the info. I know it's more of a scientific assessment, but if you observe that the RSC cats run cooler, then I'm willing to give it a shot. The thought of taking the car in 4 or 5 times to get O2 sensors fixed really bothers me. :P

While I do know quite a bit about cars in their stock form, I know very little about aftermarket parts and performance improvements. What difference will I feel or hear with the RSC cats?

btw, thanks for all the help, starting from late last year when i was looking into the idea of purchasing a Vantage.