NNH

Having received a shiny new driver's side cat under warranty to finish my previously reported CEL saga , I picked up the car yesterday morning and went merrily about my business. Until last night, when the CEL came on again. Same circumstances, about 10 minutes after leaving the freeway in Redondo.

I'm going to have a serious chat with my car tonight, to let it know that Troublesome Cars Get Traded. I may leave some 350Z/M3/RX-8/S2000 brochures on the front seat to encourage better behaviour...

Seriously though, I am wondering if my driving style has anything to do with it: on the open road I'm as gung-ho as the next guy, but in town I tend to surf the torque curve at 2000-3000rpm. I've noticed that a lot of other rennlisters claim to hit 4000+rpm in each gear, but I must confess that I had put it down to
a) hyperbole
b) showing off by making lots of noise
c) some people being new to driving a stickshift.

I humbly apologise (especially for c), and request my fellow rennlisters' input: is it unhealthy to run a 996 in the 2000-3000rpm range?

nycebo

no

rcg412

it wont cause a cel..... its probably another sensor.. .are you on your original MAF?

NNH

So far as I know, it's the original MAF. I picked up the car in May with 51,000 miles, and it's now on 64,000. It did get a new RMS just after I bought it.

LVDell

Have you checked the code? If so, what code is it?

NNH

I haven't had a chance to check the code yet. The last one was P0420, meaning a sick driver's side cat. When AMS in Carson looked at the O2 values on the other side, they were a little off, but that cat wasn't dead yet.

I probably won't have time to check the code this weekend, but I've arranged to take the car for another trip to my dealer on Tuesday.

Meanwhile, the car shows no sign of listening to the telling-off I've given it, but maybe it's thinking about it

Alan C.

When I had a bad cat on the driver's side my dealer replaced both cats.

NNH

Has it behaved itself since then? My confidence in my car as a daily driver has been dented a little.

Alan C.

I've had no problems since both cats were replaced.

99firehawk

cats dont fail too often but they do fail

JasonAndreas

I wonder if running the load factor you ran the engine at for the amount of time that you spent in the open road challenge burnt up the catalytic converters? I also wonder if changing the DME control unit programming record to the european fuel scheduling would prevent this?

rcg412

clean the MAF... mine went at about the same mileage.

NNH

It's a fair question, but I'd be pretty disappointed if a German car couldn't handle 45 minutes at speed - when I lived in Europe I took most of my cars through Germany at one time or another, and even my unreliable MG coped just fine with a few hours at 120+.

Macster

the only way the engine controller has of keeping tabs on converters is by the O2 sensors and a bad (even intermittent) O2 sensor can appear as a converter problem.

To be better able to id the culprit, O2 sensor or converter, you need to monitor the O2 sensor voltage levels.

What has worked for me in the past is to get an OBD-2 code reader/data viewer and monitor O2 sensor voltage levels -- ideally you want a reader that can display at least all 4 O2 sensor readings simultaneously.

I find this very informative to be able to compare the sensors on the two separate banks.

A mis-behaving sensor, though its behavior is probably intermittent and will remain so for many more miles -- stands out when viewed this way.

Unlikely hard driving has caused the converters to burn out.

(150,000+ miles on my '02 Boxster's original converters, and while I've never driven it on the track, it has seen some extended high speed driving out in the great southwest. I might add that one O2 sensor (#1 sensor on the passenger side bank) in that time has needed replacement -- at around the 80,000 mile mark -- and I believe one or both the sensors on the driver's side is getting close -- every once in a while engine light comes on and its usually "converter performing below efficiency" or something to that effect but when I look at the O2 sensor voltages, they indicate the sensors are not responding with their usual vigor, which is usually how an O2 sensor goes wrong -- aging causes its response time to get slower and voltage levels less. Other check engine light error codes do flag the sensors so I'm going to replace the suspected ones before I replace the converters!)

The converters can burn out if the engine's running rich, but the engine controller should catch this condition and the check engine light will flash. Only if you continue driving then could the converters be damaged.

Sincerely,

Macster.

99firehawk

ok............ your o2 sensors moniter cat efficency by comparing the pre cat o2 sesnors to the post or after cat o2 sensors. A faulty 02 sensor will usually throw a fault for o2 sensor ageing (or delay) if it becomes slow responding, if it reads out of range it will also throw a fault for the o2 sensor, its very unlikely that a bad o2 sensor will have just a fault for cat efficeny. Running rich will damage the cats but the check engine light will not flash it will come on and burn steady with o2 sensor adaptaion faults bank 1 and 2. only current fuel dumping misfires will be registerd with a flashing cel, and if you need a flashing light to tell you somethings wrong, you really need to pay more attention the the sound and feeling a misfiring car