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Discussion Starter · #1 ·
Hi all;

I replaced my rotor with a new one from IAP as I had a Alfa DOA...see other post ( a few weeks back.

Well my car fired up and idled flawlessly. I let it warm-up for about 5 minutes, all gauges (batt., temp, oil, tach) were fine. So I slid 'er in first and cruised out of the driveway, upon acceleration that car started the sputtering, gasping, "lost" compression symptoms again. :(

I checked the cap and rotor, nothing visible here or noticeable, in other words my rotor wasn't trashed from smacking against the cap.
Had someone start it again and I saw and retrieved molten honeycombed metal frags presumably from the CAT coming out of the exhaust pipe.

CAT is probably so clogged that little exhaust gases are getting past it. I’m assuming that is causing my “bogged” down symptoms?
Also how is this related to the initial rotor having to be replaced if it is related at all?

Anyone seen this before?

18,590 Posts
A failed O2 sensor will cause the ECU (computer) to go into 'open loop' mode (no sensor feedback). That open loop mode is a slightly rich mixture. If it was too rich for too long (and it doesn't take a lot of rich or long to be too much...) the catalytic converter will be overwhelmed and get clogged & break down. The older style converters (honeycomb innards) are probabaly more prone to this.

Perhaps your cat was on its last legs anyway and the failed distributor rotor was enough to push it over the edge. Or it was about to fail anyway...

Any decent muffler shop can cut out the old converter and weld in a new, free-er flowing converter. The cost should be about $75-$100US plus $25-$50 for labor. Compare that to a new front pipe w/ converter for $400-$500.

Replace the O2 sensor while you're at it (and make sure it is plugged in...).
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