What Actually Happens During An OBDII Emissions Inspection

I have seen many people talk about OBD-II emissions tests on various web forums. Often with a puzzled: “I failed readiness!” or “Do I have to do an OBD-II test on my 1994 vehicle?” Since OBD-II has replaced or will replace sniffer tests for 96 and newer vehicles in most states, I thought I’d dump some introductory information about OBD-II emissions tests for people. I don’t get into the details about OBD-II, the various protocols, or how to tune an OBD-II vehicle here. Only what to expect in the emissions process.

First, some really quick background: California required emissions control systems (Catalytic converters) on cars sold in California starting the 1966 model year. This was adopted across the US in 1968, and eventually became the Clean Air Act of 1970 which required emissions standards that were hard for manufacturers to meet. Ultimately, car makers found that switching to electronically controlled engine management allowed them to meet these demands. These electronics became more sophisticated and more standardized as time went on, and now we have a standard protocol (OBD-II) that all these computers adhere to.

Today: Many States, California, Massachusetts, New York, Illinois, Washington, New Hampshire, and on and on have mandatory emissions inspections in some or all counties. Typically this is used as part of the car registration and renewal process. Up until 2000, this just meant popping the car on a dyno, sticking a sniffer in the tailpipe and measuring what percentage of the air coming out of the vehicle is clean. However, in 2000 the EPA started pushing an “OBD-II emissions test” and many states adopted it, or are in the process of adopting it.

An OBD-II test consists of the emissions computer plugging into the OBD-ii port on the car (usually under the dash or hidden behind the cigarette lighter) and asking the car’s computer whether the emissions equipment on the vehicle is working within the required efficiency limits. This is advantageous over the sniffer because its much faster, more consistent (in theory) and harder for those of us that like fast cars to just jury rig a huge catalytic converter the morning before inspection in order to pass with flying colors in our fire-spitting vicious mobiles

The way OBD-II tests actually work, is pretty simple. The car’s ECU waits for a set of conditions that are representative of normal driving and then checks the values of a few sensors to make sure that under that condition the equipment is working exactly as it should. Typically it examines systems such as the catalytic converter, the Exhaust Gas Recirculation (EGR), and the evaporative emissions. It stores these results internally and the computer just queries for these results at inspection time. The inspection machine also checks the computer to see if any error codes are set, and if the check engine light (also know as a Malfunction Indicator Light (MIL)) is set. If the tester determines that the emissions equipment is in order, there are no internal errors which the car didn’t see fit to tell you about and the check engine light is not on, the car is given a pass without needing any further emissions related tests.

For the car to definitively say that the vehicle is in working order it needs to examine its systems for a set number of “driving cycles”. Driving cycles are defined differently for different car companies. For some a driving cycle is the time between when the key is first turned on, until it is turned off. For others, it is any 10 minute period of non-idle driving, etc. This is where the concept of readiness is introduced. When the vehicle’s ECU is reset for any reason (replacement, low battery, faulty sensors, etc) it resets the ‘readiness monitors’ inside the ECU. These are a number of flags that determine whether or not the car is prepared to validate the condition of the emissions systems. The vehicle then must be driven for a preset number of drive cycles to give the ECU all the information it needs to get out of the unready state and actually test the emissions systems.

If a car is inspected while it is not ready, the car will return ‘not ready’ to the inspection computer. On cars sold between 1996 and 2000 an emissions test is considered a fail if any 2 of the emissions systems return not ready. On later vehicles, you are only allowed one not ready. The typical remedy for failing readiness is to drive the car around for up to 500 miles and trying the test again. After that, if you still fail, a dealer or somebody with factory diagnosis equipment is required to force the vehicle to run the emissions tests regardless of readiness.

Modified Cars: OBD-II represents a problem for cars with modified emissions systems. In the past, you could just keep the factory exhaust in a corner of your garage and slap it on for inspection, but now the electric tattle-tails will still catch you. You can use a datalogger, such as the car-code logger: http://www.obd-2.com/ to check whether your car has passed readiness and thinks it is in an emissions happy state. This is of course for use with off-road only vehicles only.

A common problem for modified cars is secondary o2 sensors. Part of the OBD-II tests involves determining the efficiency of catalytic converter (or pre-cat catalytic converters) by checking the value of the oxygen sensors which are located after the cat. If your off-road vehicle does not have this equipment the vehicle will likely fail. A common solution for this problem is to install an oxygen sensor simulator which gives the car’s ECU a false signal that mimics what it is expecting to see so it thinks everything is in order. A quick internet search for “o2 simulator” will return further information on this topic.

Finally, remember that you will need to drive the car a lot of miles to get readiness to pass. In some extreme cases over 1000 miles is required. So if you are planning on taking the car down for a few months in order to do a long project, and your time for inspection is coming up you are better off getting the vehicle inspected before taking it off the road and resetting the ECU.

What Are the Benefits of Hybrid Cars and a Look at Diesel Hybrid Cars

Hybrid cars are complex vehicles that have a simple purpose: to reduce the amount of fuel emissions released into the air. Since a hybrid car combines an engine that uses gas with a motor that reduces gas consumption, these two things balance each other out to increase gas mileage.

Hybrid cars are indeed very efficient yet expensive, but looking at the less fuel cost it’s indeed a bang for the buck. The downside of hybrid is it produces less power that’s mainly why most hybrid prototypes lacks corners and edges because eliminating the drag is one way to compensate the downgrade to power in hybrids. They are not all fuel-sippers, although some have high performance and high prices.

These types of cars are economical and can get up to 55 to 60 mpg in city driving, while a typical SUV might travel 15-20 miles per gallon, or use three times as much gas for the same distance! They are better than all-electric cars because hybrid car batteries recharge as you drive so there is no need to plug in and most electric cars cannot go faster than 50-60 mph and are the beginning of the end for gasoline cars. These cars are built with much smaller, more efficient engines than regular cars. Most of the time, you don’t need the extra power afforded by the larger engine, anyway.

Hybrid cars are starting to become more popular in America, but they are still new to the car market. In the years to come even more hybrids will become available. They are starting points, not as efficient as we’d like, but they will lead to future technologies like cellulose and prairie grass, and other as yet created technologies. They are a growing market due to the obvious environmental benefits and fuel efficiency and the market is expected to continue to grow well into the future.

Diesel and Hybrid Cars

Diesel cars are less common in North America, but can still be found in use in parts of Europe. In North America diesel tends to be used in trucks rather than cars, and the cars run on gas instead. Diesel engines are present in some hybrid models, which are more energy efficient than gasoline engines. There is speculation that some companies have developed a hybrid model that runs on hydrogen fuel. These hybrid diesel cars get better bas mileage, but availability of these cars is currently limited to certain states. New technology for diesel engines redefines them as clean, low-polluting and still high-mileage.

Hybrid cars are cars that use both an electrical source and an internal combustion engine to propel the vehicle. They are as safe as any other vehicle in their class. They are given the same crash tests and scored the same. Hybrid cars are a step in the right direction but in small numbers will not have a significant impact on air pollution.

Engine Leaks Take a Brutal Toll on Cars and Car Parts

If you own a car then you have probably already had some experience with car leaks, at least to some degree. Even new cars can develop leaks that are both annoying and frustrating. In the 1980s and 1990s engine leaks and other automotive leaking problems were the cause of a large majority of auto service appointments.

Now there are better engineering designs and materials used in the automotive manufacturing process. This has resulted in a decrease in customer complaints because new car parts have been noted to have substantially less problems with leak malfunctions.

Keep Engine Leaks at Bay

For those of you that may be unfamiliar with the basics of engine seals here is a list of what a car engine needs in order to be leak-free.

1.      Motor oil

2.      Proper compression

3.      Fitted gaskets

4.      Intact seals

5.      Engine coolant

6.      Fuel

Understanding Engine Seals

Most of the seals that protect your car engine are designed with double lips so that the motor oil can not leak out. One of the seals is designed to contain the oil, and the other is meant to stop any debris from contaminating the oil system. Although these lipped seals do not move they still have a big job to do because the car parts that they are surrounding are in motion. This is why many automotive techs refer to these car accessories as dynamic engine seals.

You will find dynamic seals used on car parts that are either rotating or belt driven. Two examples of these are crankshafts and camshafts. These are crucial elements for your car engine and it only takes a small leak to create a great deal of damage. An oil leak from a camshaft seal can result in ruined valves and timing belts which are both costly repairs.

How Leaks Begin

Small bits of grit, dust and road dirt are always flying about the exterior of auto engines. If there is a small opening in any seal it can allow some of these contaminants to adhere to the inner surface. Then as the shafts are moving they are being abraded by these particles’ sharp edges.

The constant motion of these rotating and belt driven car parts will soon cause small grooves to form along the sides of the shafts. Now the integrity of the seals and shafts are both compromised. Once these irregular grooves have formed on the metal surfaces, leaking will soon follow.

Fixes for Seals

There are times when worn metal surfaces can be repaired instead of being replaced. Some mechanics are able to grind and weld the shafts until the surface area meats the necessary specifications.  There is also a slip-sleeve that is available for some front crankshafts. This product is a fine metal covering that can be applied to the damaged area and will then cover the grooves. These are both elaborate and high priced technical projects that are only suggested for ultra expensive vehicles. Car parts such as engine seals and shafts can be replaced at a more affordable cost.

Gaskets and Engine Leaks

In the past a lot of car accessories and engine parts used gaskets that contained cork. The cork would work for a while but it deteriorated at a relatively quick pace. This material would stop a leak by swelling up and forming a tighter seal, but only after a small amount of oil had leached into the gasket.

Another type of engine gasket was made from RTV silicone and this could create a secure seal but only under special conditions. The silicone base meant that it had to be applied to an engine surface that was absolutely clean and free of any oily residue. Many mechanics had trouble getting the metal surface prepped to these exacting specifications.

Most of today’s new gaskets are made form synthetic rubber compounds. These engine gaskets are reliable and are much less likely to form a leak. This is the type of gasket that is preferred by knowledgeable mechanics and auto enthusiasts.  

Gasket Seal Problems

When placing gaskets onto surfaces it seems that many auto techs and mechanics tend to tighten them too much. In order to address this problem there are some newer designs that use metal spacers. These spacers are actually in the gaskets which helps prevent the over tightening seen in the past. Newer car parts such as the cast aluminum engine covers and those made from plastics have also been responsible for protecting gaskets from this common problem.

There are also some gaskets that are more likely to be the source of engine leaks even if they have been properly installed. A car’s head gaskets and those used on the intake manifold are the ones that should be checked first if an engine leak is noted.

Internal Manifold and Head Gaskets

Engine compression, coolants and oil all depend on an intact head gasket seal. The intake manifold gaskets that are on cars are responsible for insuring the integrity of coolants, gas and diesel fumes and air. If these seals are damaged, or compromised you are assured of having leaks from your car that are going to be noticeable.

Engines and Aluminum Car Parts

The fact that so many engine car parts are now made from aluminum is an additional problem. Because of this metal’s expansion and contraction the gaskets must be allowed some movement allowance. This means that a mechanic needs to make sure that when the repairs are done the gaskets are capable of allowing for the movement of internal car parts as the temperature and weather changes.

Torque to Yield Bolts

Gaskets are internal car parts and they are placed in areas where bolts are going to be required. A mechanic can use incorrect bolts or too much torque and this will result in gasket failure. In this type of situation there could be a compression leak or coolant leak from head gaskets as well as warping of the heads. To prevent this from occurring most auto shops are now using the type of car engine bolts that are known as “torque to yield”.

Check and Repair Engine Leaks

No matter how old, or new, your car is you will need to check on any type of coolant engine leak. Just 2-3 tablespoons of an antifreeze liquid seeping into the oil compartment could ruin some vital car parts. Antifreeze and oil is a mix that can ruin the bearings in any car engine.

If you do not want to take your car to a garage you can handle the situation yourself. Certainly there are many different products that you can use to repair gaskets and seals. Your mechanic or auto supply store can help you find the right one for your vehicle. Just remember if you are doing the repairs yourself you need to make sure that you are using a quality product and applying it correctly. Follow the specifications and make sure to clean the surfaces properly and have exact alignment before making the repairs.