Hello,

I've posted another thread as quoted below. The skinny: my cars been stalling and it threw a P0420 code (see quote below).

I pulled the CAT Converter and I want to find out if it's bad. From what I understand, I should be able to look through it kinda like an airlfilter... is this correct. If it's plugged, I really shouldn't be able to see any light get through... is this correct? Thanks... Rob

" Hello People of HT,

First off, thanks for being available to answer questions... a much appreciated service you people provide free of charge.

Problem: I own a 99 Civic EX, 4 cyl., auto that has developed a stalling problem. The car starts and idles fine, has 166k miles on original engine.

When driving, it might stall at any speed, and I can sometimes restart the engine. Engine will always crank, but restart is questionable and pretty intermittant. When it stalls, it usually does so when the engine is warm, although outside temp might be cool/warm or whatever.

There is a solid, amber, check engine light on and it threw the code P0420, pertaining to a possible catalytic converter issue. I erased the code and have since stalled it, but no engine light or thrown code has come on. Upon stalling and attempting to restart, I noted the "battery" dash light linger for a second or two... no restart; able to crank, lights on, no dimming. This morning, started like a champ... no idle problem.

Also... this problem, or a similar one, occured about a year ago. I ended up replacing a ICM (I believe... don't remember) which didn't resolve problem. I then read up on a recall for the ignition switch, which was replaced by dealer, resolving that problem.

I have read that due to this particular code being thrown, it is nearly always a bad cat, not being a tech or having advanced diagnositic equip or experience, I just don't know, but my gut feeling is that this problem is electrical (I know this sounds vague, but again, I'm not sure...).

Q: any chance it threw this code as the vehicle was stalling due to a condition that developed when something else was crumping (like an electrical problem... ignition... coil... main relay...), and not a cat problem?

Q: Can CAT's be checked or cleaned?

Q: If indeed it's the CAT, any good online sources for an OEM parts?

Q: How can I proceed to diagnose what I can at home?

Any help or alternate thoughts on what could be going on would be very appreciated....

Best Regards,

Rob "

 

usually when the cat goes bad there is a great loss in power, and sometimes in an automatic stalling can be an issue. Here are 2 ways to tell if your cat is bad. 1st drive it for about 15 min leave the car running, now look at your cat is it glowing red or does feel like it might be extremly hot. Second thing you can do is drill 2 holes in the cat, 1 in front and 1 in the back. The don't need to be really big. If it's hot it's clogged, the holes are so that it can let gasses out. So if it runs better with the 2 holes your cat is clogged

 

Thanks for your reply, Lompseg, I looked at the converter and it's toast; all crumbled in the center with a broken honeycomb on the upstream side. Can't really look through it either. The new one you can see about a dime sized section of hazy sun when I look through it. Also, the O2 sensor was fried. I ordered the new cat, and two sensors... perhaps my problems might be solved when the repair is over. Thanks, Lompseg. ~ rob