hgaa

I am a new member to the club and have a problem with my 834 GSL-SE. I've had the car since new and never had any problems. For the first time in 18 years, I have failed the Ohio E check. The HC levels are 700PPM vs 189 limit. The CO is 3.37% vs 1.21% limit. Took it to the local Mazda dealership since no one else will touch the rotary. They were no help. I've changed the plugs, air filter, and O2 sensor but no help. Also noticed a significant drop in fuel mileage. Any suggestions?

RX7 8U

iTrader: (1)

Cat is probably plugged and shot. Replace at muffler shop not dealer if you want to save money or maybe you'll find a good one in a junkyard.

nelam

I don't think you can by a used cat from a junkyard. It is the law in CA at least.

RotorMotorDriver

iTrader: (1)

Yeah, you probably need a new catalytic converter, or two.... When they get old, they tend to fall apart internally, which causes a backup in the flow which would result in your drop in gas mileage, and also would cause a drop in power. Mind you you may not notice all this all at once (probably wouldnt), but I bet you would tell the difference after you got it all straightened out . I know that there are like 2 or 3 cats on these cars, I would think that you dont want to pay to get all three replaced (expensive, but try Victoria Bristish if you wanna go that way), so maybe talk to a few shops and see if they can get you something put in there so that you only need one (high flow) cat maybe? This may give you a little more power too, but not much (if any) with the rest of the exhaust stock. Just my thoughts. Hope it helps .

~T.J.

genrex

I have a stock GSL-SE. The problem is usually not with the two small pre-cats.. the problem is almost always with the main cat. I recently had to get mine replaced because of similar problems.

I suggest that you get a stock GSL-SE main catalytic converter. I bought a Walker-Dynomax cat after performing an extensive internet search on RX-7 cats (including on this forum). I was led to believe that these cats were just as good as (or better than) stock cats.. but after only two weeks I knew that wasn't true. The cat is proving to be a daily embarrassment. And I'm kicking myself, especially because the price turned out to be the same (as a stock GSL-SE cat), after new flanges had to be welded in! So there was no benefit to getting an aftermarket cat, and the quality was not as good, but the price was the same.

RotorMotorDriver

iTrader: (1)

Hows that?

~T.J.

hgaa

Thanks for all the posts. You all are leading me to replacing the cat. Are Victoria British exhaust parts the way to go or is there someone else out there? I am not in to racing the car so I'm not into the performance parts. Just want the car to run as well as it should and has in the past.

85RX7GS

iTrader: (1)

I believe that Victoria British has a stock exhaust section on page 63 in their "Fall Edition" catalog. It looks like you'd want part number: 53-422 entitled, "Converter-Rear-Replacement" for 84-85. Good luck with your car.

RotorMotorDriver

iTrader: (1)

Victoria British doesnt just make exhaust. They publish a magazine which sells stock exhaust parts (as well as just about anything else you would need for your car), which is what I was thinking (or a high flow cat) for you in your situation. Check them out and order their free catalog at: www.victoriabritish.com . They were just the first people that sell the stock cats that I could think of.
There ya go . Now all you need to do is get the catalog .

By the way, welcome to the forum. I hope you get all the help you need here. BTW...Wheres Error402 with the welcome message?

~T.J.

hgaa

Thanks to all. Will give the replacement cat a try and hope that solves the problem. I have enjoyed reading the posts on other subjects. Sure am glad I found this. There is only one dealership in town and I am not impressed (not that I ever was impressed with any dealer). No one else wants to touch the rotary. At least now there is a place to go where die hard RX-7 owners are willing to help each other. Thanks a lot and I will post the outcome when I get the repairs made. Maybe I will help some one else in the future.

TheBigOne

Your car is not failing by much. HC's are pretty easy to fix.
Retard your timing about 3-6 degrees

hgaa

Do you not consider 700ppm vs 189ppm for HC significant? Do you think just retarding the timing is all that is needed? I sure would hate to put a new converter on and find it's just a timing problem. Your thoughts are appreciated.

fatboy7

I'm not sure if retarding the timing would help much.... It seems that it would heat the cats up well, but at the same time making them work overtime, due to less burn time at idle before hitting the exhaust. It could work (ie if replacing the cats doesn't work... and you're desperate, try this)