I just got back from trying to smog my 85 GS and they told me I need a cat. I got rid of the stock cats a while ago and replaced them with one "highflow cat" a local muffler shop put on. The smog guy said first thing first, I need a new cat and my car is also running rich.

About the running rich thing, about a week ago I was messing around with my idle mixture and idle speed. Ever since then my car has felt weaker up top. Almost like my secondary's aren't opening up. In the mornings when I try to start the car it takes a while. But when the car is warmed up and been running for a while it fires up right away. The tach initially fires up to about 2k and comes back down to idle without me pushing on the throttle.

First, where can I get a cheap replacement for my cat? I found a Catco off summit for $100. Will it work?

Second, Whats up with my mixture and how can I fix it. Do I have to rebuild it or can I tune it? Thanks in advance.

 

Mixture screw only affects idle circuit mixture, so it wouldn't be the cause for problems at low end.

 

where to get the actual cats Complete Exhaust

and for reference Car Sound By Magnaflow

Cat Specs


as for the idle, that will be for somebody elses help.

 

how did you "adjust" the idle? Also, in my experience from getting my 12a to pass smog, it's a lot easier to find someone with access to a gas analyizer to adjust to idle and stuff for smog purposes. Try a new cat first, cauz it was probably some generic cat and got burned through, but the new one probably won't last long either. Also make sure your air pump and acv is working properly.

Alvin

 

Idles mixture screw affects idle & low speed AFM... Follow the adjustment in the FSM. Paraphrasing; With the engine hot, turn the mixture screw in (lean) until the idle starts to drop. Then back off 1/4 turn. Then adjust idle speed.

I would adjust the idle before you replace the CAT...

 

Thanks for all the input guys. The mixture and idle are fine I followed the proper procedures. But since then, maybe just a coincidence, my car has felt real weak. Usually at 4k I would feel my secondary's open and little more power. It doesnt do that now. Would a bad cat cause this? Basically what Im trying to ask is what will cause a 12A to run rich? How do I check if the air pump is working properly? Thanks again for all the help.

 

Which cat do I get? 93514 or 94014?

 

I have a good almost brand new cat. $100 plus shipping or you pick up in LA.

 

What 'highflow' cat do you have? When I bought my 85GSL from a guy in Atlanta, he had installed a Bonez cat and midpipe and that sucker had great emissions readings!

 

What brand is it? Direct fit or universal?

I don't know what brand it is but I know for sure its not a bonez. I think it might be a catco.

 

the 94014 has a higher test weight, but i dont know what effect that has on emmisions since our cars are nowhere near that weight.

I personally would use the 94014 because the higher test weight. my thinking is a heavier vehicle would require some harder work and therefore more emmisions.

 

In my experience w/o the anti-tamper cap on the mixture screw, it just vibrates loose (rich) over time...

Your 4K problem could be a number of things, including a clogged fuel filter or a collapsed CAT.

The air pump is a pretty simple and reliable device. The ACV and control is another story. It directs air to the CAT or the manifold depending on conditions. At idle it should send air to the CAT.