Plugged cat?: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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Dec. 15, 2008 7:04 a.m. petegossett Dork

I'm starting to think my wife's '00 Villager may have a plugged cat, or at least one that's starting to get plugged.

It had been running fine up to a couple weeks ago, but now after it gets nice & warm(after driving on the highway 1/2-hour or so)you can feel a slight hesitation when you're idling at a stop, or when the van is in park. It's not a normal 'miss' - the plugs & wires are new, anyway. There's also a strange "putt-putt" sound from the exhaust. Oh, and there's no codes(Well, none other than my usual Evap codes I've been getting for the past 2-years).

Our mileage has only dropped by about 2-MPG, which is about normal for the switch to winter-blended gas(which I'm guessing is already at the pumps).

So, what are the normal signs that your catalyst is failing? Most stories I've read make it sound like one day it's fine & the next it's completely plugged, but is that always true?
Dec. 15, 2008 7:39 a.m. 44Dwarf Reader

Check temp at inlet and out let pipes if its cloged or not working the outlet will be colder then inlet if its working out should be hotter.
Dec. 15, 2008 9:17 a.m. Strizzo Dork

could also crawl under and give it a whack with a rubber mallet or something, if you hear pieces rattling around in it, then its no good
Dec. 15, 2008 10:21 a.m. iceracer Reader

A loss of power would be noticed. It can be checked with a vacumn gauge.
Dec. 15, 2008 12:24 p.m. GameboyRMH SuperDork

Strizzo wrote: could also crawl under and give it a whack with a rubber mallet or something, if you hear pieces rattling around in it, then its no good

Oh boy PETA is going to shut this forum down...
Dec. 15, 2008 12:51 p.m. Capt Slow Reader

When the CAT plugged up on my wife's 1984 mazda GLC there was very little notice.

It was kind of funny when it happend, we were driving along on hwy 17 arguing about the "burning smell" comming from her car. As I was busy telling her, that her car always smells like that, I checked the rearview mirror and noticed a little more smoke than ususal, and the car was running rougher than normal.

After pulling over to investigate we found a rubber hose that was part of the EGR system had overheated and caught on fire. Which we promptly put out with 1/2 a pint of water we had left in a waterbottle int he trunk.

The plugged up cat had forced exaust through the EGR system and overheated it. Being young and stupid at the time I took a hammer and a screwdriver to the cat and "fixed it good" got more power out of the car after that too...
Dec. 15, 2008 1:05 p.m. noisycricket Reader

Take an old 18mm spark plug or O2 sensor, gut it so only the empty shell remains, tap for pipe thread or otherwise mod it so that you can stick a hose on it. Connect to a pressure gauge and drive it.

A clogged cat is usually bad enough that it keeps the engine from going over a certain RPM. I did have one in a Corvette where the engine would stall immediately after starting, and wouldn't restart until the exhaust pressure blew past a convenient open valve and through the intake or past the rings. Zero vacuum when cranking.
Dec. 15, 2008 2:25 p.m. petegossett Dork

Thanks for the replies. It doesn't sound like I have a plugged cat - for better or worse.

Unfortunately, there isn't a lot of tech support for these vans on the internet, so I'll just tell her to keep driving it until something more serious/obvious breaks.
Dec. 15, 2008 4:49 p.m. benzbaron New Reader

I know an O2 sensor will give you strange issues when they start crapping out. I think mine is going on the pickup b/c it runs strange/hiccups when the car is cold only. I think the O2 sensor is probably causing the my car to run strange until the car warms up and the EFI system goes to closed loop.

Good luck!