rlaifatt

My CEL has been on since the last track day, code reader says secondary O2 sensor, and I can hear some rattling in the cat when idling. I was assuming that it won't affect the engine since the primary O2 sensor should be okay (so I kept running it without incident at last track day at Fontana), but is there any risk if the cat physically deteriorates further? E.g., coul exhaust flow be impaired causing damage? Bottom line is, is it safe (to the engine) to still track the car for 2 days this weekend?

mikegarrison

I would think the biggest risk is that the cat could plug up. This would probably not "hurt" the engine, but you would experience a decrease in power until you replaced the cat.

Slows2k

I've seen convertors that have caused some serious performance issues when they become clogged. If the catalyst bed breaks up it can restrict the exhaust. If the exhaust is really well blocked, the exhaust gas will back up to the engine and super heat eveything. Valves, valves seats, cylinder walls/rings can all be cooked. You can make the call on safety,but I wouldn't track the car.

A cheap fix would be a test pipe and 02 simulator for "track use"

rlaifatt

Uh oh, this is not sounding good.

Anyone with a spare converter that you could bring to Willow Springs this weekend?

Prolene

I'll have Kyle haul ours out for you to use, if you want.

rlaifatt

Thanks Al! I would appreciate that. I am assuming it won't be too difficult to do at the track with the car on jackstands.

I expect I would be able to get it replaced at the dealer under warranty, but don't have time before the weekend.

BTW, what's your excuse for not coming?

Prolene

'Tis my weekend to give surgical coverage. I'll let Kyle know.

tinkfist

Bump. My CEL went on at the track, mid-turn, a couple weeks ago and this was my code as well. I ran the rest of the weekend with no problems. I am wondering though if the cat or the oxygen sensor has gone bad. Richard, what did you find out? Anyone else having cat/O2 issues from tracking?

Car has 62k and 20+ track days on it.

CKit

I've had a cat go bad with the same rattling and 2' O2 code.

I wouldn't be surprised if: you toasted the cat, causing pieces of the honeycomb to dislodge... shearing the head off the O2 sensor.

Does the cat rattle? Bring WD-40 to help with the bolts. Spare cats are abundant on the forum (or just bring a test pipe for track days).

It's easy to take the O2 sensor out (standard spark plug socket IIRC) to check. Aftermarket replacements are available <$100 at your local Advance Auto Parts.

davepk

A word of caution.

Do not put a replacement O2 sensor into the cat that a bad(broken) O2 sensor was removed from.

You'll end up with two broken O2 sensors if you do.