hard to smog 87 rx7 and getting harder?
 

I recently acquired a 1987 RX7 na auto. I live in San Diego And am having problems smoging my 1987 Mazda RX7 na auto. First test failed, high HC and high NOX.Did some research and was advised to change plugs, wires and o2 sensor. Second test, failed high HC. NOX levels came down to well within range but HC did not move.How do you lean these things out? The cat is the next issue. Where to get one new and cheap ha ha. Thanks Tim Reed P.S. I hear that the regs are going to change on april 5th making it harder to pass.

yep your right and now that the muffler shop don't use universal cats cause is illegal. thanks to arnold the terminator u have to buy from magnaflow witch will be one for your rx7. i believe your 7 has 2 cats, be ready to pay around 200 to 350 for the cats they are very expensive.:banghead:

just throw some denatured alcohol into your gas tank...it'll help lower the HC

ok, let's get our information straight here.

Tim,

You didn't mention an oil change. That should have been done first.

Second, you only need to replace the main cat. You don't need to buy two cats.

It'll be $200 or less for a muffler shop to weld in a Magnaflow to replace your stock main cat. That's a fresh new cat and labor, so that's not expensive, considering your cat's almost a quarter of a century old. The Magnaflow is about 20 lbs lighter and will flow better than your FC cat that was designed in 1985.

Since you're close to passing, the new cat should be enough for your FC to pass. That should be it.

However....

You can also pick up a can of fuel additive called "Guaranteed to Pass" (or something like that) from your local car parts store. Follow the directions exactly. The stuff only makes a little bit of a difference, but that may be all you need.

If the car still does not pass, the next step is to replace the EGR valve, which may also be on it's way out. However a defective EGR valve should have given you a warning light. At any rate, you might want to replace it anyway, and over it's lifetime it will pay for itself with better fuel economy.

If it doesn't pass after the O2 sensor, oil, plugs, cat and EGR valve, you're going to need a rebuild or another motor.

This helped me a lot when I was having smog issues....

https://www.rx7club.com/showpost.php...06&postcount=4

Denatured alcohol will certainly help your car pass on hydrocarbons... Also make sure your airpump is working correctly, that has a lot to do with emmisions on an Rx7.

I do agree replacing the cat with a magna flow or a bonez or something of that nature will probably help. You can get a muffler shop to throw in a cheap imitation cat as well, sure it is illegal but most shops will still do it.

proven by Import Tuner that is dose not work just a waste of money just invest in a new cat for sure to pass, if you want hook me up with lunch and gas money and ill let you barrow my new cat only used it once for the smog and took it off cause I'm rolling with the Racing Beat exhaust.

Always do a service befor you get a smog. Change the oil, air filter, fuel filter. The Alcohol does work but I dont think its the HC/s that it fixes. Its the NOX. With the Alcohol in the fuel it burns cooler. Also drive the car about 5+ miles before you take it in.

well in order to get t better score you need to have the CAT very hot before you go in so i suggest you make an appointment with the smog guy 30 min before the test have least 3 gallons of gas jump on the freeway for while for like a good 10 miles pull over drop in the Alcohol start driving towards the smog station while its still nice and hot. jump on the machine and be amazed by the results. but i highly suggest you get a new main cat.

PMing you now..

coz of this thread, prices on an old school smog exempt RXs just went up by 33%.

^pm that guy:D

cat cost
 

My mechanic found one local for $150.00 plus $50.00 labor to install. He also reset the idle mixture variable lean rich mixture and air flow. This brought the idle down to 750 rpm where it belongs and drastically reduced fuel intake. I do not know how long the car was run so far out of adjustment but I am sure long enough to torch a cat. I had already changed the oil and filter. The car now runs really good and should pass smog with a new cat. Thanks to all for your input and help. Tim

good advice and offer.
 

I assume your cat is a bolt on. Nice offer thanks. My car is stock and will probably stay so until it gives up. Then on to better things.Do you live in Oceanside. My email address is tp.reed@hotmail.com Thanks

second gen not hard to smog
 

My 87 rx7 hasn't been a big problem once I got enough information. My car does run cool. I will post my results next week.

o2 sensor lowers NOX
 

Putting in a new o2 sensor lowered the NOX well within range. The alcohol should burn clean as it has zero hydrocarbons.

I don't know any of the scientific specs on it... but I know from experience that denatured alcohol lowers HC. This I know because another club member brought his car to me, I put it on the dyno and HCs were way to high. He comes back the next week with a can of denatured alcohol... and a 1/8 tank of gas... puts the alcohol in and drives it around.. we put it on my dyno and HCs dropped dramatically, enough to pass. Yes we did immediate before and after readings of the car when putting in the denatured alcohol.

Sorry don't know the theory though on why it lowers HCs.

so no cat or hollowed cat means high HC right? so would this denatured alcohol stuff help to have it pass?

yeah its a bolt on with the air pump flange

cat scratch fever
 

One causes the other. If your car is running rich. There will be left over fuel for the cat to deal with. The substance inside the converter neutralizes the HC (unburnt fuel ) and if you don't correct the extra fuel problem you may pas the test but you you will soon burn out the cat and get bad fuel mileage. If you do a tune up,replace the o2 sensor and put in a new cat it should pass with out the worry of putting weird stuff in your RX7. Converters are are available on Ebay for about $100.00.

yea but are those 100 dollar ebay cats cali legal

^ Nope. Doesn't mean you can't put one on. Most techs don't even check to see if it has the appropriate stamps on the cat. Denatured alcohol trick without a cat probably wouldn't pass either.

just as long as it looks like its a stock cat it should be fine?

^yup... as long as theres a cat there who cares... I know I dont look for stamps or EO's on cats:D

legal cAT
 

yES THE $100.00 CAT IS A Magnaflo ca.cat. The illegal ones are about $60.00.