[urq] Catalytic convertor problem

[Buchholz, Steven]

... newer cars have two OXS sensors ... one before and one after the cat ... the ECU checks both sides and decides if the cat is bad.  I don't think a 1988 90 would have that (my 1991 V8s don't).  I'd expect the 90 to be like your urq ... there's a "CO Tap Tube" somewhere in the engine compartment; you test the cat by checking the exhaust gasses before the cat here and then compare the results with the tailpipe numbers.  

Reading your post I'm wondering why it matters.  If you can fit a test pipe (thought I saw one posted on the AF marketplace late last week) who cares if the cat works or not?  As long as the one you have isn't plugging the exhaust or rattling around it sounds like you can leave well enough alone.  

If you want to replace your cat, my recommendation is to have a muffler shop take your old one and weld a replacement cat in place.  high flow cats are pretty widely available on line ... and they don't cost that much.

Steve B
San José, CA (USA)

PS ... out here in Kaleefohnia I hear there are now folks crawling under vehicles and hacking the cats off to be sold for the precious metals!!!  It is an amazing world nowadays ... who needs anarchy?  I guess it's better than waking up in a bathtub full of ice and finding you're missing a kidney!  :-)
> 
> I hope someone can help me with a catalytic converter
> problem on my 88 Audi model 90 Q.
> 
> How does one check for a catalytic converter gone bad?
> Does anyone have a phone No. or the name of aplace to
> purchase a one, new or used??
> 
> Has anyone replaced the converter with a straight
> pipe?? If so can anyone suggest a place to purchase
> the pipe? I think the converter has a flange at one
> end. Thanks a bunch in advance.