lowrider65

i took my car up to echeck and i passed everthing but HC i have 324 ppm and the limt is 181ppm i have no idea what this is can somebody help me out and tell how to fix it

vaughnc

tuneup will cure most of that. Also drive the car for 30min beforehand and keep the revs up if you have to wait at the emission station.

13bpower

there are also ways to cheat. putting alcohol in your gas (about 20% diluted) causes everything to burn hotter, there for 'fixing' the problem. I use gas line antifreeze. I would only do this if nothing else works though.

selanne8

does your car have a high flow cat or gutted cats? if you've done anything to your cats, put back all the stock stuff.

i 2nd the tune up (plugs and wires esp if you haven't changed those out in a while).

one other thing to check is the acv (air control valve)...mine was busted and wouldn't let me pass smog during idle.

john

deadRX7Conv

What year car? What mods?
What were the CO/NOx numbers?
HC=unburned fuel
Time for a tune up.

lowrider65

i have 86 gxl i just put new plugs in it and the only engine mod is a k&n fipk how many cats are on it i heard there are three and i only have two

KNONFS

iTrader: (14)

All you need is:

A good cat (make sure is heated before the test)
A working ACV
A working Air Pump
Spark Plugs in good condition

lowrider65

CO 0.45 limit is 1.16
Co2 14.15

lowrider65

i turned the rich and lean screw when was putting in a new motor and i dont know if its set right or not but could turn it to run leaner will that help at allor not

EndlessRPMs

what exactly is the rich and lean screw?? i need to make my car run leaner...please gimme details!

HAILERS

The variable resistor (rich/lean) might very well help. It only has an effect at idle though. No other time. Also make dang sure your acv is working right. See http://iluvmyrx7.com for a free download and just download the 4A Fuel section.

The rich/lean screw is only available on the good models of the RX7, the 86-88 years. Sorry.

KNONFS

iTrader: (14)

Actually I think is the other way around, I know there is one on the AFM in the 89-91

HAILERS

Here's a jpg of the one and the only variable resistor with the rich/lean screw:

deadRX7Conv

Run a couple bottles of FI/topend cleaner through it. Or get a Fuel Injector service. Use low octane(87) fuel. Replace the catalytics. It all depends on how much money you have to spend.

Hydrocarbons (HC)-Gasoline consists of hydrogen and carbon atoms, thus levels of hydrocarbon represent unburned fuel in the exhaust. Identified in parts per million (PPM), this is the emission that makes your eyes tear (catless rotary) from the exhaust of a poor-running car or an engine with a large cam(port change). Mistakenly thought of as a rich air/fuel (A/F) mixture, HC is known as a misfire meter. HC levels escalate when the engine is not experiencing complete and efficient combustion. Residual HC is created by ignition problems, excessively lean A/F mixtures, and excessive crevice volumes or carbon deposits in the combustion chamber.
Carbon Monoxide (CO)-Measured in percent, CO represents partially burned fuel created by a lack of necessary oxygen to support combustion. Simply put, whenever CO readings are high, the A/F mixture is overly rich. A failed CO test indicates a plugged air filter, poorly adjusted carburetor, high float level, high fuel pressure, dirty injectors or degraded oxygen sensor, or fuel dilution in the crankcase.
Carbon Dioxide (CO2)-As a by-product of the bonding of the carbon and oxygen molecules during combustion, C02 demonstrates how efficient the engine is running. It is measured in percent.
Oxygen (02)-Defined as a colorless, odorless gas, this is the most common element known to man. During an emissions test, high levels in the exhaust represent additional oxygen molecules that do not have a carbon element to bond with. Oxygen readings increase if the mixture is excessively lean and also during scenarios that would normally promote high HC levels. If the fuel is not being burned, neither is the oxygen. Usually inversely proportioned to C02, 02 is measured in percent.
Oxides of Nitrogen (NOx)- Measured in PPM, NOx is present during all phases of combustion but escalates dramatically when leading-edge flame-front temperatures are in excess of 2,500 degrees F. Requiring heat, cylinder pressure, and exposure time to be produced, detonation is a leading source of this pollutant. Exhaust gas recirculation (EGR) valves are used to cool combustion chamber temperatures by introducing inert exhaust gases. It may be hard to grasp how hot exhaust can cool a combustion chamber, but it actually functions by consuming space in the bore, thus limiting cylinder fill rates with a combustible mixture. Since NOx production is highest under part throttle light load, when the A/F mixture is the leanest, NOx became the impetus to mandate the I/M 240 schedule.
The Catalyst: Friend or Foe?
An emissions-control device in the exhaust tract is an attempt to correct what could not be controlled in the combustion chamber. Simply, a catalyst speeds up a chemical reaction without being consumed itself. In effect, the catalyst "scrubs" the exhaust. Early catalysts were filled with pellets made of 70-percent platinum and 30-percent palladium. The pellets were eventually replaced with a ceramic monolith that combined a larger surface area with smaller exterior dimensions. Not all catalysts are effective on all emissions. Application-specific catalysts are designed to neutralize certain elements. Oxidation catalysts convert CO and HC to C02 and H20, while reduction catalysts treat NOx by converting it back to nitrogen and oxygen. Dual-bed designs are a melding of two different catalysts that affect NOx in the first section and CO and HC in the rear section. Three-way catalytic converters simultaneously scrub all three exhaust gases in one unit.

lowrider65

i checked my air pump and acvand they both work fine is there anything else i should check

jb4bama

I had the same problem with my 91Turbo, and all I did was run it hard to a testing station that was further from my house. Also, I don't know how they test in OH, but in GA they are allowed to test the car one of two possible gears. MAKE SURE THEY TEST IN THE HIGHER OF THE TWO GEARS ALLOWED. I tested two days later with all of this and passed. The key is keeping the cat hot.

88TurboII

Change the cats, plugs and wires and you will likely pass unless you have an engine problem (vacuum leak = lean = fail, etc). New cats make an amazing difference. They're not all that expensive, I did mine mail order from a net search. Some say it's difficult to get a wankel to pass, but that's bs in my experience.