Coov

iTrader: (1)

Could definitely use some help. We just bought a 93 RX7 and it is not passing the smog test. It is 6 times over the limit. The engine is running very rich.

The car has 51k miles, and has a stock ECU. The changes from stock are:
M2 Cold air intake, downpipe, and Racing Beat catback exhaust. The stock catalytic converter is still in place.

Is there anything besides the ECU's air fuel mixture control that would cause this? Are the modifications listed enough to cause this if I am running the stock ECU?

Thanks.

Coov

iTrader: (1)

Looking into it maybe being the emission system. No check engine light. I will need to see if the air pump is working properly. Is the air pump enough to cause it to fail smog by 6 times the amount it should be?

Coov

iTrader: (1)

Come on guys. Somebody here has to have some good advice.

The air pump is fine, but it is not getting a signal to stay on below 3500 rpm like it should. The relay to the pump is also fine. The O2 sensor checks out. The map sensor checks out. A signal comes into the air pump for a split second, you see it start to spin, and then it immediately shuts off.

The car is rich and running way over the smog limit, but otherwise is running very well. The ECU is stock, if I didn't already say that. Still not sure what is going on.

robtoyz

Do you have a copy of the smog? What are the reading?

Coov

iTrader: (1)

They only tried it at idle since it was so far out of whack.

Here are the numbers:

CO2 % O2 % HC(PPM) CO2%
Test RPM MEAS MEAS MAX GP MEAS MAX GP MEAS Results
Idle 718 9.4 0.2 100 250 3136 1.0 2.5 7.72 Gross Polluter
2500 2459 9.9 0.1 130 280 640 1.0 2.5 7.34 Gross Polluter

MazdaSpeedDan

iTrader: (4)

Wrong injectors could be causing this.

juicyjosh

iTrader: (29)

If the air pump is not running, then that's most likely the reason it's not passing. You may also consider replacing the EGR valve and getting a fresh cat. A muffler shop should be able to weld in a new one - most likely an "OEM replacement" Magnaflow - for around $200 parts and labor. (You'll automatically make the car 30 lbs lighter just by doing this btw, in addition to the car running cooler and having a better-flowing exhaust.)

Coov

iTrader: (1)

Thanks guys. I will try the cat replacement in a bit. So here is the latest. The air pump does work. Putting a jumper across the connector and forcing it to stay on not only gets the pump working, but it now also passes smog.

So, the big question is, why is it getting a signal to start when the car is turned on, immediately followed by a shut off? The pump works, but the ECU is not telling it to stay on. Again, O2 sensor is fine, and map sensor is fine, and with the air pump forced to stay on, it passes smog. Any ideas?

Thanks.

Rotary77

check the injectors and if they are upgraded then more than likely if the person tht did tht should have been smart enough to upgrade the fuel pump also

MazdaSpeedDan

iTrader: (4)

bad circuit?