RXForTheRain

It's a 1987 N/A.

I got rid of my 2 pre-converters and nuclear reactor, and replaced with an RB header and a Mazdatrix hi-flo cat and from there back it's standard. I love the sound and the throtle response (and it runs a lot cooler!) - but it failed emissions for the first time.

Here's the dyno results:

Parameter Result Limit

HC (PPM) 51 160
CO (%) 0.52 1.1
CO+CO2 (%) (not part of test) 15.52 6


Here's the idle results:

HC (PPM) 216 220 (damn close!)
CO (%) 2.1 1.2 (FAIL)
CO+CO2 (%) (not part of test) 16.4 6

As I said, it's never failed emissions with the standard setup. I understand it can be leaned out/riched out, but from my *limited* understanding, one way will increase HC, another will increase CO%. I'm at the limit on HC and CO% is failing. Plugs/wires/O2 sensor all fairly new, the K&N could use cleaning. Appreciate any help.

RoadRaceJosh

There are plenty of threads on this very subject. Search and you shall find. BTW, running rich causes the high CO and burning oil causes high HC. Misfires also cause high HC, but it's usually really high.

evileagle

iTrader: (1)

I think I talked to you on the phone a while ago......



Lean out your idle mixture via the variable resistor. Until that beast almost dies at idle. Make sure that you CLEARLY MARK where it was before so that you can set it back AS SOON AS YOU ARE DONE SMOGGING. Please don't blow up your engine. I had the same problem on my TII.

RXForTheRain

Does everyone but me know where this is? Is it the same adjustment as for the idle, on top of the throtle body?

I searched the 2nd gen forum for "emissions" got 500+ hits.

I got a new O2 sensor since there's no way for me to test it, and I don't know how old it is.

The BAC sems to fail the test described in the workshop manual, unplug it and no engine speed decrease. I'm told it can be disassembled and cleaned, so that's next.

I have some stuff called "Emissions Test Formula", add it to a full tank of gas and run it down to almost empty and retest. Doesn't say anything about rotaries on the package, but we're used to that, right?

RXForTheRain

It was buried under crud and RTV.

BAC seemed to be failing, took it apart, put it back together, and replaced the O2 sensor. Now BAC seems fine.

I'll lean it out and retest next week.