argonsoon

As the title says i went to get me emissions test to day after running it long and hot for about an hour and a half i pulled into the testing station kept the rpms up at around 2k while i waited (not a long wait) and ended up getting these results

Idle 1 HC (220 pass) CO (1 pass)
440 1.6895

Had me run the engine at 2500 rpm for acouple seconds

Idle 2 HC CO
608 1.5869

i have no idea what i can do to help it, i even spent the arm and a leg to put a good tank of premium NO ethanol gas to help it out....any advice would be a god send...please help me.

j9fd3s

iTrader: (3)

check the Air Control Valve for proper operation. shop manual is here Foxed.ca - Mazda RX-7 Manuals

argonsoon

so went into testing today, had about 13 gallons of normal 10% ethanol mixed with about 3 gallons of e85 and i also disconnected my secondaries just for ***** and giggles. hydro carbons i got 428 and 510...however the Co level dropped down to .1939 and .1798.....so something i did whether its the gas mixture or the secondaries being disabled really helped the CO level. now to try and fix the hydro carbon level.

argonsoon

it should be noted that a guy i know plumbed the air pump straight into the exhaust to dilute the levels, and i never had him change it back so im pretty sure that my air pump is bypassing my air control valve.

rotordogg

iTrader: (4)

Causes for high hydro carbons are:

1. rich mixture in carb
2. Faulty catalytic converter (or no cat at all)
3. low compression on engine

Or any combination of the above.

I'm assuming this is a 12a?

rotordogg

iTrader: (4)

I guess I should add a failed air pump to the list.

I'm sure you already know this but Hydrocarbons are simply un-burnt fuel. Even a properly tuned Rotary emits HC's. This is why mazda used that big bulky thermo reactor and three catalytic converters. The thermo reactor got super hot and helped burn HC's exiting the exhaust. The catalytic converters continued the process.

I would do the following:

1. Check the exhaust system, make sure you have a catalytic converter that works and an air pipe from either the ACV or directly from the Air Pump.
2. Make sure the Air Pump is working.
3. Check the engine compression
4. Follow the FSM for idle and timing adjustment. You can always warm it up, lean out the mixture a little and have the test done and then return to a normal/slightly rich adjustment. My 12a had high HC's and the mechanic doing the test was nice enough to simply adjust the mixture screw until it passed.

The E85 produces less CO so that is how you got that number to fall.

j9fd3s

iTrader: (3)

just judging by your numbers something there is amiss. the air pump and ACV are crucial to passing smog, if they aren't working it'll never pass unless you live in a state where their standards are really lenient

Qingdao

iTrader: (3)

Run a little propane through your carb hat. Do the inspectors check under your hood? would they notice an LP regulator?

Cameron38

iTrader: (2)

According to Mazdatrix, If your O2 reading is less than .5% and HC and/or CO is high, it's most likely the Air Control Valve.

argonsoon

no they do not do an under the hood inspection to my knowledge, however i have heard of them "investigating" if the reading are absurdly low or non existent. but have never witnessed it first hand. yes it is a 12A. tomorrow im going to go into round 3 of testing and lower the mixture, (it has always been on the rich side) and turn up the idle to compensate, hopefully all of this will work. I have read on a couple other forums of people even retarding the timing a bit and having gotten good results. Anyone ever done this?

rotordogg

iTrader: (4)

Adjusting timing and the mixture screw will help but not if you set the idle too high. Your carb has an idle circuit that controls, along with the mixture and air screw, the amount of fuel at startup and idle. Once the idle and air flow exceed a certain amount, the fuel delivery is determined by the size of the jets.

If you are at 2000 rpms, your HC's are going to be higher than what you can do at idle because the engine is delivering more fuel via the jets.

I didn't see it above but did you verify there is a catalytic converter on there? I highly doubt you will pass if you don't have the cat and working air pump/ACV.

argonsoon

yes it does have a cat on it, and i just ran it through 4 more times while trying to tweak the carb...only managed to get it much much worse. i think im going to pay someone to tweak it to spec for me if possible.