Passing smog
- Thread starter Dannyp1
- Start date
- Status
Oh. Move.
From the sheet it look like you need a new Cat and then you'll be fine... in any other state other than California. There it will depend on the guy at the inspection station.
More info and questions for you.
Basically you failed because the converter either wore out, or, the car ran pig rich and the raw fuel ruined the comverter.
Little science lesson for you. Its called the catalytic converter because theres a mix of metals that has changed over the years that act as a catalyst to change those compounds youre failing for into different ones. The catalyst is a metal/chemical that contributes in a reaction but remains unchanged/unconsumed after the whole reaction is complete. In many catalytic converters platinum used as catalyst that converts unburned hydrocarbons into H2O and CO2. Thays why scrappers pay so much for them. If there is too much unburned gas (hydrocarbons) going in the converter, it overheats/increases the temps inside. This hugher temperature causes the platinum to oxidize into platinum oxide, which CANNOT act as catalyst anymore. Anothet issue can be the heat melting the screens inside, same end result. At that point, you don't convert the excess gasses, and they pass through unchanged meaning failure.
So, first off replacement cats don't use as much expensive metals and are cheap. That's the good news cause you need to replace it.
Step two is addressing why the car ran rich and appears to have dumped enough raw fuel in there to cause the overheating cause you're just going to hurt it again.
I bought an '86 GN years ago and took it to get tested. It had 25K miles on it and was all original, so I figured it would be a snap. After the test, the dyno operators says, it just barely failed for HC's and CO... It probably need a new cat.
No problem, I took it home, unbolted the downpipe and cut the cat off. and looked inside. It was completely hollow. I bought a $95 Cat off Ebay, using a band clamp to hold it in place and after it passed I swapped the hollow one back on for a "test pipe".
That new cat only had about 100 miles on it when I sold the car.
No problem, I took it home, unbolted the downpipe and cut the cat off. and looked inside. It was completely hollow. I bought a $95 Cat off Ebay, using a band clamp to hold it in place and after it passed I swapped the hollow one back on for a "test pipe".
That new cat only had about 100 miles on it when I sold the car.
Your visual past - failed CO & HC and not by a little, why I asked if the car was in tune.
Common Reasons for Failure
1975-1995 Gasoline Vehicles
1996-Current Gasoline Vehicles
1975-2001 Diesel Vehicles
2002 and Newer Diesel Vehicles
What Are the Most Common Causes of Failures for 1975- 1995 gasoline vehicles?
These are general guidelines only.
High HC Emissions
- Inoperative/missing catalytic converter
- O2 sensor malfunction
- Internal engine problem
- Vacuum leaks (hoses, vacuum operated devices, intake manifold, carburetor)
- Ignition system malfunction (plugs, plug wires, points, dwell, etc.)
- Improper fuel injector operation
- Incorrect ignition timing and/or idle speed
- Incorrect carburetor air/fuel mixture
- Defective EGR valve or air injection system failure
- Excessively rich air/fuel mixture
- O2 sensor malfunction
- Faulty computer control(s)
- Malfunctioning fuel injection system
- Inoperative/missing catalytic converter
- Carburetor float level maladjusted
- Air cleaner, choke or carburetor
- Defective canister purge system
Possible Causes of High Hydrocarbon (HC) Emissions
Hydrocarbons relate to unburned fuel. You may logically think that must mean that the engine is getting too much fuel. However, that is only one of many possibilities ranging from fuel problems, to electrical problems, to internal engine problems such as piston rings that can cause HC emissions to be excessive. In order to pinpoint the cause of excessive HC emissions, the following systems (if applicable) will need to be checked, usually in the order shown below:
Lean or Rich Air-Fuel Ratio
For an engine to operate as designed, the correct ratio of fuel to air must be delivered to the cylinders. If the fuel system is delivering a leaner than ideal air-fuel ratio, it may result in lean misfire and cause high hydrocarbons. If the fuel system is too rich, it also may result in high HC but will be accompanied by high CO as well.
Inadequate Catalytic Converter Efficiency
For vehicles that are 1988 model year or newer, it is very important that the catalytic converter be operating at 90% efficiency or better. That means that the emissions that come out of the tailpipe must be no more than 10% of what goes in.
Induction System Problems
There are many aspects of the engine’s air induction system (hoses, intake runners, intake manifold, vacuum-controlled devices) that can cause disruption in the air and fuel getting to the cylinders and result in high HC. Incorrect PCV valve/orifice flow rate can also cause similar symptoms. Leaking EGR valves also may cause excessive HC emissions.
Poor Ignition Performance
Ignition defects including dirty spark plugs, leaking or open-circuited spark plugs or wires, or defective ignition coils can all result in a shortage of spark energy. Any shortage of spark energy may cause high HC emissions.
If the spark occurs at the wrong time, incomplete combustion and high hydrocarbons may result. Too much spark advance could be due to an incorrect adjustment or a defect in mechanical or vacuum advance mechanisms.
Uneven Output Among the Engine’s Cylinders
At this stage of the diagnosis the technician should be sure that the air-fuel ratio is correct, there are no external vacuum leaks, and the ignition system is operating normally. There are still many possible causes of high hydrocarbons, most of which are either internal engine problems or tough-to-detect induction system problems such as valve deposits or a leaking EGR valve. On fuel-injected vehicles, poor fuel atomization is a common cause of HC problems.
For all of these remaining possibilities, checking for uneven power output amongst cylinders will usually help to track down the cause of the problem.
Possible Causes of High Carbon Monoxide (CO) Emissions
High CO means too much fuel. Fuel can only come from three sources: the crankcase vapor control system, the evaporative control system, or the actual fuel delivery system.
The fuel delivery system is certainly the most likely culprit but in most cases it is very quick and easy to eliminate the other two possibilities first. However, if it is problematic to check the evaporative system purging, it is probably wise to go straight to fuel delivery system diagnosis.
In order to pinpoint the cause of excessive CO emissions, the following systems and possible defects will need to be checked, usually (but not always) in this order:
Excessive Crankcase Blowby or PCV Flow
If oil vapors in the engine’s crankcase are excessive, or the oil is dirty or contaminated, excessive CO emissions can result. Dirty or contaminated oil is easily rectified by an oil change. Excess crankcase vapors flow can be caused by an incorrect PCV valve or by serious internal engine damage such as worn-out piston rings. Serious internal engine damage can only be remedied by major engine repair or overhaul.
Saturated Evaporative Control System
The charcoal canister stores fuel system vapors until they can be withdrawn and burned in the engine. Under normal circumstances, this should never result in excessive CO for more than a few seconds. It is possible for charcoal canisters to become saturated with fuel. This essentially means that they can never be cleared of HC vapors and need to be replaced.
Rich Air-Fuel Mixture
There are many aspects of the engine’s fuel delivery system that may need to be checked when diagnosing a rich air/fuel mixture. That is the main reason that this is listed behind crankcase vapor and evaporative emission control systems-even though they are less likely causes of the problem, they are much easier and quicker to check.
When diagnosing a rich air-fuel mixture, it is important to keep in mind the possibility of a defect in an entirely different area affecting the operation of the fuel delivery system. For example, certain mechanical engine defects may cause abnormally low engine vacuum and result in the fuel system delivering more fuel than is actually needed by the engine. The symptom of excess CO may lead one to think that the defect lies with the fuel system but the problem actually lies el
|
- Status
