Bambam7

Well, I have a brand new cat, and a new engine a few months ago, I just went for emission test and flunked horribly!! My CO was 8 times the limit!! (almost 5%- with a cat!!!)
The car is obviously running horribly rich, blows some brownish smoke under full throtle, and it has a bad full throttle, low rpm stumble when you hit the gas... EATS gas like crazy... the problem is, the dealership isn't certified to make emmisions repairs!!!! SO I have to have some monkey mechanic check it out... Does anyone have any ideas?? My guess is one of the injectors stuck open or something..(I dropped one while installing the engine, and the green plastic around the nozzle cracked, but the body seemed OK).

TPS is good, MAF seems okay, no codes for O2 sensor, but I didn't test resistance on it yet... HELP!!! PLease!!

rx7_ragtop

I would change the O2 sensor anyway. How is your airpump? (if the cat isn't getting enough air that would cause it!) Could be the injectors I guess... but that seems strange.

Six Rotors

iTrader: (17)

What are the other numbers?You need the airpump and the ACV to working as designed otherwise you don't stand a chance.It's not air to the cat which is the problem because under the Ontario testing regime(25/25) the air does not go to the cat it goes to the exhaust ports.How is your AFM mounted?If you have it at a strange angle that could be a problem.How is your idle?

Bambam7

Well, my NO was very low, it passed easily, (around 100 ppm, limit being 940 or something), and the HC was at 614! (limit is around 80 or something). The idle is a little erratic, and it backfires a lot.
All the signs point to running very rich, (plenty of black carbon in my 2 day old exhaust!), but how do I check the AVC? Whenever the car is running, it seems like the air is always coming out of the dump under the air dam, Under what condidtions is it supposed to go to the cat??
PS, does anyone know the proper voltage range for the O2 sensor?

Six Rotors

iTrader: (17)

While your car is idling and up to about 3500rpm(forget the exact rpm)you should see or feel little air coming out of the vent under the skirt.Most likely problem is the temperature switch,corroded connectors,broken wire or defective switch.The switch is located at the bottom of the radiator,driver's side engine compartment.When the water at the bottom of the rad is~15C or above this switch must be closed.
Did your car star idling crappy after installing your intake?

Bambam7

The idle is a little funky, though not even that noticable...- it varies about 30 rpm or so through a 2 or 3 second, inconsistant cycle. The engine is street ported though, which could account for it... It has been like it since I installed the engine...the intake was installed on the previeous engine as well, and I don't think it made a difference in idle.. The idle will change tone too, every few seconds it will sound lighter, like it's not working as hard, then bog down a few rpms and sound raspier and as if it's working harder...It isn't an even bouce like with a the other common idle poblem on RX-7s
I will check my ACV valve too, but I would like to get to the bottom of the combustion issue (I know it's rich) before trying to cover it with emmisions control devices....The way I see it, if the engine is properly tuned, you shouldnt need the air pump at all!
If I can't track down the problem I guess I will just buy a signal modifier for the MAF and adjust it with the A/F meter... I hate Band-Aid-ing a problem though....

Six Rotors

iTrader: (17)

You do need the air pump fullstop.The reason is that the combustion characteristics of a rotary(due to long narrow combustion chamber and other things)results in high HC and low NOx.Air injection is required to finish oxidising the HC.