Hello, I recently bought my RX-7 and it is bone stock in the engine bay. Still the same intake box and everything. Only mods are the exhaust system. I have the 3" Racing beat downpipe, the rest of the piping I am not sure about but it is 3" the whole way.

When I took my car to be smogged. It failed the emissions test. Not from visuals but because my readings were too rich.

I don't know the condition of the catalytic converter, could that be the main problem? Or would a 3 inch pipe or something else be the problem?

 

Please post the result of the smog test. Without the readings it is hard to diagnose the real root problem.

-AzEKnightz

 

Here is a pic of it.

 

It looks like your cat might be the main problem here. You HC readings are HIGH both at low speed AND high speed.

At the same time, you CO is also reading much higher than normal at higher speed.

I would check your spark plugs to make sure they are in good condition. If not, replace them with new wires as recommended.

Then, I would also replace your CAT as you do not know the condition of the CAT.

Before you bring it in the shop, make sure you are driving the car on the freeway for at least 20-30 minutes to be sure that it is fully HOT. ALSO make sure the car does not idle too long in the shop before it is being smog.

Hope this helps.

-AzEKnightz

 

Hello everyone, I have since tested twice and failed each time. Both for my HC's being high again. I have since replaced the CAT with the Bonez high flow, the o2 sensor, spark plugs and the Air pump is definitely working.

WHY am I still failing? Is it because my engine is street ported/ because I have a stock ECU? what is it?

 

Hey just to add, this engine passed easily with stock ECU and good stock cat, about 3 months ago when it was in my FD



RX7s almost never pass CA smog with an aftermarket cat. Does that cat have the air pipe hook up to it?

The stock cat is HUGE and weighs something like 40lbs with all the piping. A small highflow cat CANNOT clean up the exhaust of a rotary, which is always high in HC and overall pretty dirty.

Are you sure the O2 sensor is working properly? You should see a good sweep with a scope or multimeter hooked up. Does it cruise at 14-15 afr? Is the signal getting to the ECU okay?

Is the fuel pressure okay?

 

The cat does have an air pipe and it is hooked up. I've changed the O2 sensor twice just to make sure. After driving the car and letting it warm up, it has high 13s at idle and low 14s cruising and flooring it around.

Thoughts?

I havent checked fuel pressure yet.

 

Might have to borrow a stock cat and precat.

 

I had a similar problem when I bought my FD. It was because the vacuum lines for the rats nest was hooked up incorrectly, so double check if they are routed correctly.

 

hey takumi, I might have another stock cat I can sell. You in vacaville, CA right? I personally would not like to ship it as it is heavy as hell. Let me double check my garage this weekend and i will get back to you. I thought I sold it, but I might still have another.

-AzeKnightz

 

I would say he would have more problem he needs to worry about before emissions if vacuum lines are mis-routed.

-AzeKnightz

 

Working air pump + OEM CAT are your best friends!

 

True, but I'm just saying that all it took was two incorrectly hooked up vacuum lines made my car idle really rich.