Is there anything I need to know about stock N3A3 computers for a 5-speed, california '93. I need one for smog, my M2 computer keeps the idle too rich for the test. I was wondering if there are versions (early) that need avoiding, and maybe somebody has one that would work???
Thanks, Peter.

 

The M2 ECU upgrade is just a stock ECU that has different fuel maps for higher boost levels. It doesn't do anything different at idle.

I suggest resetting the idle to about 950 for the test. This helped me to pass with my M2 ECU.

 

Thanks, but my narrow band a/f meter shows the mix to go to about 12.0 at 800 rmp, and I think it should be at 14.7. I trust the a/f meter because it shows readinngs I would expect at other rev/poere ranges.

 

And at 950 rpm it does what????

 

It does very much the same. Maybe a 0.3 better. It is not until 1500 -> 2000 rpm does it move into the 14.7 range and then at 2000->2500, with no load, it goes way lean, off scale > 16.0. Left running with no load at 2500 gets the turbos to glow!!!. It is such a weird divergence from approx 14.7 I thought it had to be computer controlled.
The engine runs fine, its a new engine, starts hot or cold, boosts to 14 lbs, pulls like a bandit, everything else about it is perfect. I just ahve this rich idle. Which doesn't effect the idle in anyway.

 

this is normal for a rotary engine, its slightly challenging with a good ECU like a haltech to get a mildly or stock ported rotary to idle in the mid 13's, 12 or therabouts at 800 rpm is normal on a stock ecu. This is due to port overlap, and its effects at idle, and this is also why the car must have an air injection system.

 

So the concensus is that it is not the computer. Then I have another detail to reveal.
I had a CARB full flow cat put on because the car came with just one main cat and failed the visual at the only smog shop in town (bumfuck Redding) that would even look at a rotary without giving up and asking where the engine was. So the muffler shop has a 30-gas sniffer and even at idle the HC's were within range (<100). At 2500 the car showed as a zero emmision car.
I take it back to the one smog shop in town that will even look at it and they say it still has 600 (6x max allowable) at idle!
PLease don't tell me to move... I know I know.

 

I'm surprised that they found out that the precat was missing ............. unless you showed them

 

Was it cold???

I passed smog at a california ref station and at a random test only station with no pre cat.

If I where you I would get one of the cheap drynomax (carsound) spun ceramic type converters. These are real small and cheap, and look like a little premuffler, but are stamped as being CA legal. Hollow it out, and have the muffler shop weld it in.

When my maincat melted (which was the same dynomax cat mentioned above) I did this with it and put another main cat in.

 

I've been to three test only smog stations in the Bay Area and none noticed the dowpipe. I don't understand why the other shops refused your car because it was a rotary. The smog software has options for rotary engines.

 

I've had that happen in the past, but not for a long time. The last smog I got the guy commented on how it was a real strange 4cyl for the spark plugs to be sideways and not in a line.