Just hook up your scanner and look at each sensor reading on a fully warm engine. Write them down. rpm, O2 sensors, IAT, MAF. STFT, LTFT. engine load, engine temp, timing, etc.

 

If you didn't have a rattling noise from the exhaust I'd suggested checking the O2 sensors, but given the rattling noise you probably have a damaged cat. As 1999 suggested, assuming you've got a well tuned system you shouldn't have damaged the cats just with the use of the SC.

 

I'm guessing it's probably just getting old. My car is an 02 with 30K miles.

 

Hard to say about an old car with only 30k miles. I have a 2000 with 107k miles. Started throwing P0420 and 0430 codes. Some times it was just the gas I got. Later it was more consistent. I changed out all 4 O2 sensors now after 1k miles no codes.

 

I can scan a bunch of different things, but not all of them at once.

Here's an excel file of some of the sensors that I thought would be useful. What's your diagnosis Doc?

 

One thing I noticed is that bank one, sensor 2 (if I'm reading that correctly) seems to be consistently lower than bank one, sensor 1.

 

What can happen, is the Catalyst material can break free from the walls of the cat causing the rattle sound, more so usually on cold starts, until it heats up and can have a tighter fit inside. If you do choose to stick with OEM, shouldnt have a problem with this item falling under emissions warranty, which I believe is 8/80K. Regarding the numbers, Sensor 1 is reading before cat which should be an oscillating signal, rich/lean/rich/lean, this is the DME controlling the air/fuel. Sensor 2 should be as level as possible, as no oscillations mean a properly functioning cat converter.

 

Bank 1 and 2 ran different on my engine also and not sure what sets the CEL off except the difference between the before and after O2 readings per side, I am not sure what if any measurements sets it off because of the difference between banks. Check your resistance readings on your O2's, mine read an infinite reading on one of them and that was my clue. Also running the software when driving the car thru different RPM's and loads may show something also while logging your data.

 

The first thing that jumps out to me is the low MAF reading. You should have a reading of about 0.80 - 1 at idle. Being this low can cause a lean condition. What are your fuel trim readings?

 

I don't know. I'll have to warm it up again tonight and run a seperate set of sensors. I'll log them and repost. This obviously was just sitting at idle in my garage.

 

Out of curiosity (And completely unrelated to this issue) but, when was the last time you changed your plugs?

 

When I had the kit installed It's been a couple years and probably at least 10K or so miles. Bob said don't worry about it right now if it's running well. What do you think?

 

It might be a good project for the winter. DO NOT use platinum plugs. Use copper and gap to around 0.026 - 0.028.

 

Is there anything on the supercharger kit that interferes with the plug install? I'm trying to gauge how long this will take.

Why no platinum? Is there a particular brand you recommend?

 

No interference from SC system. Other than GOLD, copper is the best conductor of heat and will transfer heat from the cylinder better that a more expensive Platinum plug. Reducing the pluig gap will allow for more consistant spark at extreme rpms.