I'm trying to pass PA state inspection/smog. The machine says I don't have enough exhaust coming through to measure emissions??? WTF? The mechanic and I checked for exhaust leaks for about 10 minutes and we couldn't find anything, just the air whoosing back up through the ACV. The muffler was replaced with a stock Mazda unit about two years ago. I pulled the cats and it's a straight through pipe with some matting at the top and bottom. I thought cats usually had pellets through the middle? Anyway, the cats looked like they should flow MORE air, not less. They certainly aren't clogged. Can the cat still be bad even if it's essentially hollow? Is there something wrong with their machine? Is there anything else I should look for?

Kev

 

Pellet cats suck ***** even when they work.If you still have the stock pellet cat I can almost gaurantee it doesnt work.The pellets between the mats will blow out eventually.They can refill them,but its hardly worth the effort.Best to just switch to a modern monolithic brick cat.
If whatever cat you have isnt working,theres no way youll pass anyhow.
It might be that theres just so much HC and so little oxygen in the exhaust,the machine cant take it.I remember once Sport Compact took an 83' into a smog shop with a bad cat and it smogged somthing like 2,500 PPM of HC.After the headers and a new Random Tech catylist went on,it dropped to only 4 PPM of HC.Max is usually around 120-175 PPM of HC.

Sometimes you can pack the exhaust with rags after inserting the probe.Itll help prevent bad readings from reversion and excess oxygen contamination.I had to do that once when I tried to smog a car with a big 4-5" exhaust tip.

 

Did rexes come with pellet cats from the factory? This one looks pretty stock, but it's hollow.

Kev

 

I have a replacement pipe where my cat goes, It has flanges and everything. I dont have e-check anymore, but when I did I just switched the cat out after the test. But you probably are just better off getting a BD monolith replacement.

 

What year is your car ? SAs (79/80) didn't have an cats, they had an air pump with a heat exchanger thang ( can't rememeber the correct term for it right now ) instead which pumped fresh air in and was supposed to help burn the extra HCs to make it pass emissions. If your in pittsburgh go see if someone in butler county can do your inspection, we don't have emssions checks there. I'm up in Zelienople and don't have to worry about this crap.

 

What year is your car ? SAs (79/80) didn't have any cats, they had an air pump with a heat exchanger thang ( can't rememeber the correct term for it right now ) instead which pumped fresh air in and was supposed to help burn the extra HCs to make it pass emissions. If your in pittsburgh go see if someone in butler county can do your inspection, we don't have emssions checks there. I'm up in Zelienople and don't have to worry about this crap.

 

Excuse the double post, I must have hit the post button twice.

 

My folks live in Cranberry, but I made a HUGE mistake and registered it to my Pitt address when the title transferred. I could wait another 3 or 4 weeks for the registration to come in the mail so I could switch my home address, but I need the car starting on Monday. I don't want to leave my nova in the city. I'm ordering up a replacement cat, which by the time I show them receipts for spark plugs, wires, cat, etc, should go over $150, which will make me emission exempt anyway.

I'm actually in Cranberry right now if you want to hang out this weekend.

Kev

 

The SAs had thermal reactors, the FBs had the honeycomb style cats. If you have an SA, the reactor may appear to be open, but they and the exhaust manifold can collapse, manifold in particular and block the exhaust.

 

Thremal reactors, thats the ticket. I couldn't remember what they were called but I knew the principal they used to clean the emissions up:-) Old age I guess.

 

You'll see or hear me around. I have a silver 80 GS with a black bra on the front. The body needs work but it runs very well. I'll pm you when I get a chance, this weekend I'm already pretty booked up.