it passed inspection, 15mph and 45mhp. only thing it didn't pass is 25mph. He said the mixture is too rich. the car is totaly stock, only thing it has is a down pipe. could that case the A/F mixture to be off? is there a way to adjust the mixture? this is a car that i suppose to pick it up tomorrow. bylaw he can't release the title until the car pass smog. any suggestion?

 

put the first converter back on, i am no expert but i think having the downpipe could cause it to run rich b/c of less restriction. i have a 90 w/ full racing beat exhaust, runs rich as hell..

 

having the downpipe cause it to run richer? it seem to me it should be leaner? is there a way to lean out the car on low rpm?

on the test sheet show.

HC( PPM)
Meas is 58

CO (%)
Meas is 0.77
can someone tell me what the hell are those numbers mean?

 

HC is hydrocarbons, basically measures how much unburnt fuel particles are being emitted. This is usally the high # on rotaries because they are tuned so rich, the catalytic converters take care of this by burning it off in the exhaust.

CO is carbon dioxide, a byproduct of combustion.. this is typically very low for rotaries in comparison to piston engines.

I would venture to guess that you passed on CO2 and failed on the HC? Put on the precat, it will help to reduce your HC I guarantee it.. having a downpipe will not make you run leaner at idle or partial throttle (which is all they measure), it only affects WOT conditions.

Matt

 

Most likely it needs new PLUGS and/or O2 sensor. Make shure the coolaant is fully up to operating temp and the cat is HOT when tested - Do a couple WOT blasts to redline just before the test to blow out excess carbon from the cat and get it good and hot so it is operating correctly. There is no Mixture adjustment per-say mixture is controlled by the cpu & O2 sensor - a BAD O2 sensor can cause it to run rich so put in a new O2 sensor along with the new plugs. also Dirty / Leaking injectors will cause it to run rich.

 

Good points maxpesce, I had a problem passing smog with my old trusty Integra last time. I replaced the plugs and O2 sensor, ran it on the freeway and got it real warm.. passed like a charm after that.

Matt

 

I may be wrong but CO is carbon monoxide.

Carbon dioxide, CO2, would be produced in abundance by any internal combustion engine.

Ed

PS I was a chem major so I should know.

 

Thats another thing, did the guy you are getting it from make sure the car was warm when he tested it? Sometimes the mechanics will let the car sit (doing other stuff) and cool down, so when they go to test the car it is not warmed up yet. make sure the car has been well warmed immediately before they test it. I know my car passed with a downpipe and catback(not that that affects it) but with no pre-cat cars have been known to pass in CA.

 

That's why you make an appointment for first test of the day.

 

the guys said he drove about 20min to the testing place, i'm assuming the car is warm up then now? he will try a different place tomorrow. as far as i know he changed the plug, wires and 02 on his last tune up. about 4 months ago. could the 02 is defected? i'll let you guys know tomorrow.
thanks for the help

 

Make sure that the guy does NOT push the gas enough to get boost gauge above 0 psi when speeding up, its hard to do but very important.

You do have a gauge, right?

Make sure that the engine and exhaust are hot and make sure that they have a fan in front of the car.

I passed with 96K on a stock engine, stock twins, air pump, stainless steel downpipe, and the stock ecu.

 

Putting the Precat should not make a difference, it is only there for cold start emmisions, before the main cat warms up. The testing shall only be done on a warmed up engine, "maxpesce" advice is good

 

Nice to know, I'm going up for a smog test in 4 months. Think I'll change my o sensor and plugs before then

 

On my test sheet it says my car has "Cylinders: 17" now did I get a hook up? Because it still has all my model, make, and vin number so I thought the computer sets things up.

This is what it looked like with just a RB catback...

15 MPH -- 25 MPH
Limit | Reading -- Limit | Reading
HC ppm :: 136 | 28 -- 132 | 38
CO % :: .76 | .00 -- .73 | .00
NO ppm :: 1045 | 317 -- 945 | 345

 

My only contribution to this thread..

You are indeed right, CO is Carbon Monoxide while CO2 is Carbon Dioxide.

I've got my DP and MP on but a cat-back and I was still running rich. Make sure you check your plugs and O2 sensor as well..

 

Just bribe the INSPECTOR..

Working for 7/hr. a $50 or Cnote would
be hard deny.. = )

 

And then maybe when you're out of jail, the emissions standards will be lowered... and you'd pass!

 

Many thanks for all the help. We changed the 02 and the plug, the car passed not problem yahooooooooooooo, i'm picking the car up tonight. Now let's talk about mods lol thanks again

 

Sweet man..good to hear..a little maintanence does go a long way with the RX7..