Repair And Fix it

The exhaust gas recirculation valve, or EGR valve, is part of the Mercury Sables emissions control systems. EGR valves, which were introduced in the 1970s, are now included on all automobiles in the United States.

Purpose

The EGR valve, usually located on the intake manifold, reduces oxides of nitrogen (NOx) that form in internal combustion engines when temperatures reach 2,500 degrees Fahrenheit or more. Nitrogen and oxygen combine to form NOx, a component of smog.

Function

As its name implies, the EGR valve recirculates exhaust gases back into the combustion chamber. Because the exhaust gases cannot be burned again, the result is cooler temperatures in the combustion chambers---several hundred degrees cooler. This reduces the production of NOx.

Performance

The creation of the EGR valve has enabled auto engineers to design more aggressive timing for engines, increasing efficiency and, as a result, improving fuel economy. A malfunctioning EGR valve, however, leads to engine ping and knocking.

Intake gaskets seal gaps between the intake manifold and the cylinder head. They are made in thicknesses ranging from 0.060 inch to 0.120 inch. If too much air gets into the system, the car will not run properly.

Intake Manifold

Gaskets are located throughout the engine, but one of the most important parts of the engine is the intake manifold. The intake manifold regulates the amount of air and fuel your engine gets to create the combustible reactions that power the business. The gaskets can withstand temperatures of 500 degrees Fahrenheit and higher. Some gaskets are made from high-temperature plastic that actually cools the air that passes through them.

Gasket Problem Symptoms

You know that your intake gaskets are no longer doing their job if you start seeing puddles forming under the car when it is in park or when you see a leak in the coolant system. Also, if your engine is rough and slightly jerky, or if you hear whistling from the engine taking in excess air, you have problems with your gaskets.

Repair

A vacuum gauge that checks manifold pressure is used to find the leak. All coolant must be drained from the vehicle and the manifold must be removed in order to replace the gaskets.

Warning

In the book, "Small Black Chevy Engine Buildups," the editors write that with too much air "your engine will turn into melted cheesecake; too little and itll drive like melted cheesecake."

Proving yet again that the only bad question is the one not asked, heres one with a few different answers. They all involve a "yes," but with a few provisos -- primarily in terms of filter location. The Optimas automatic transmission underwent a few changes in the middle of the 2001 model year that determine where youll find the filter and how youll go about changing it.

Filter Locations

According to Kia technical service bulletin TT651003-005 -- published in the wildly popular Kia Technician Times, Volume 6, Issue 5, 2003 -- the company switched from external to internal transmissions in the middle of the 2001 model year. This goes for both 2.4-liter four-cylinder and 2.5-liter V-6 engines. Check the VIN number and the exact production date of your Optima; cars produced from October 1st, 2000 to December 31st, 2001 used transmissions with an external filter, while later models used an internal one.

A Cause for Change

External filters are a nice touch when it comes to maintenance, but theyre uncommon for one primary reason. If youve ever been under your car, youll notice that Kia left just about enough room for a snake to slither through. While this wasnt anything that Kias engineers couldnt deal with, this particular transmission also saw use in the same-year Sonata, Santa Fe and Trajet; and, Kia being Kia, also likely had designs on selling the design after its production cycle to another manufacturer. So, out went the external filter, and in comes the internal one.

Replacing the External Filter

The external filter is great from a maintenance point of view. It screws onto the the transmission case just above the transmission fluid oil pan and should be clearly visible from the bottom of the car. You should be able to get to it from the top after removing the air cleaner assembly. After removing the old filter with a filter wrench, clean the mating surface and the surrounding area, lubricate the O-ring on the filter and tighten it to 8 or 9 foot-pounds.

Replacing the Internal Filter

Internal filter transmissions are more compact by nature, but changing the filter is a comparative pain. But little more so than any other car. Slide under the car and remove the 10 millimeter transmission pan bolts, starting at one side and working toward the other. Be prepared for transmission fluid to cascade out of the top of the pan. Scrape any gasket material off of the transmission and oil pan. Youll find the filter secured to the bottom of the transmission, inside the pan, by three bolts. Remove them, replace the filter, and reinstall the pan. Tighten all of the bolts to about 10 foot-pounds and ill the transmission with 3.5 quarts of SP3 transmission fluid.

A Chevy exhaust gas recirculation (EGR) valve is a necessary part of the cars emissions system. It works by rerouting some of the exhaust gases back into the intake manifold rather than into the atmosphere.

Types

There are several types of EGR valves with the same function but different modes of operation. Older EGR valves are purely mechanical and run on vacuum; on many newer Chevrolet and other GM models, the valve is controlled entirely by computer. This type uses multiple solenoids to open the valve in response to input from the cars computer, opening and closing the valve to allow exhaust gas flow.

Operation

Whether the EGR valve uses vacuum or electronic control, it opens when exhaust gases reach a certain temperature or level of backpressure. When the EGR valve opens, some of the exhaust is rerouted to the intake manifold. Since it is less combustible than the air-fuel mixture in the manifold, the temperature drops.

Functions

The main function of an EGR valve is to lower the amount of nitrogen oxide a car releases into the atmosphere. A failed EGR valve prevents a car from passing emissions testing, if required. The valves secondary function is to lower the temperature in the intake manifold.

Plug wires arent the most glorious part of any engine, but they are a bit more complicated than most give them credit for being. While wire length may not seem particularly critical, those wires carry an enormous amount of high-voltage power. Pay close attention to your plug wires, or they may end up sending a message that leaves you saying "Can you hear me now?"

Plug Wire Factors

Two things come into play when discussing spark plug wire length: the resistance of the wire in ohms, and the amount of radio frequency interference it produces. The ohm is a measure of a wires efficiency in passing electrical current. Smaller and less-efficient wires rate higher in ohms, meaning that theyll convert more electrical energy into heat in the plug wire instead of passing it to the plug. Resistance in the plug creates a discharge of positive radio waves, which ground out in a cars stereo system and create static through the speakers.

Ohms and Wires

Different grades of wires produce various levels of ohms per foot. An average stock spark plug wire creates about 5,000 ohms of resistance per foot of length; high-performance wires will average between 100 and 400 ohms, and high-grade race wires may go as low as 2 to 10 ohms. If you apply Ohms Law of voltage loss (Voltage Loss = amperes flowing through wire X ohms of resistance) to a typical high-performance ignition system where the coil produces about 20,000 volts and sends about 0.010 amps to the wires, youll find that a stock wire will cause a drop of about 50 volts per foot, a performance wire will drop about 1 to 4 volts per foot and a race wire might drop as little as little as 0.02 volt per foot.

Voltage Output and Plug Length

Since resistance to flow increases by wire length in feet, multiplying the spark plug wires length in feet by its voltage loss per foot will tell you its impact on spark plug power. In the worst-case scenario, assume that a stock 5,000-ohm wire measures a whopping 4 feet long. Thats a 200-volt drop from ignition coil to plug wire -- a seemingly insignificant 1 percent drop. However, that 200-volt energy loss will go into creating heat in the wire, and ohms of resistance go up with heat. The end result is a cascade effect of failure; the current flow and heat gain will eventually reach an equilibrium, but not before producing a noticeable drop in current, damaging the wires conductive core and hindering its RFI-suppressive qualities.

RFI and Solutions

You can get away with using longer plug wires by using a lower-resistance wire, one thats either thicker or higher quality. However, higher current flows also produce more RFI, which means that youll also need to use a high-quality RFI-shielded wire to prevent interference through the radio system. Even if you never listen to anything but MP3s and CDs, remember that RFI interference is an extremely broadband signal. Under certain circumstances, this signal can reach into the frequency ranges commonly used for cell phones and other communications devices, effectively scrambling the signal. So, if your phone seems to constantly drop calls while in the car, you might want to take a look at those old, cheap or mile-long plug wires.

Replacing the engine oil in your Volkswagen VR6 with the appropriate engine oil weight is important to maintain proper engine function. The type of oil you use depends on the weather. Oil that functions well in southern Texas may not be appropriate for winters in New England. By taking into account the temperature and information from your owners manual, you can determine the best oil to use in your car.

Temperature Considerations

Temperature should be a primary consideration when choosing engine oil. If you are going to operate your car at temperatures below 15 degrees Fahrenheit, choose an engine oil with a first weight of 10 or lower (e.g. 10W30, 10W40). If you are going to operate your engine above 100 degrees Fahrenheit, use an engine oil in which the second number is at least 50 (e.g. 10W50, 20W50).

Manufacturer Recommendations

VW recommends engine oil meeting Volkswagens "502.00" engine oil standard. Many oils meet the quality standards for Volkswagens 502.00 standard.

Approved Oils

Before purchasing oil, check the bottle or manufacturers website to make sure the oil conforms to Volkswagens standard. If you have any questions, contact your local Volkswagen dealer.

An exhaust leak can negatively effect the performance and efficiency of your vehicle, as well as lead to safety hazards for the driver and passengers. For this reason, you should diagnose and repair the exhaust system immediately when you experience symptoms of an exhaust leak. To eliminate leaks, the exhaust system must be free of piping damage, and all of the exhaust flange bolts must be extremely tight.

Safety Hazards

Exhaust gasses contain carbon monoxide and other chemicals that are hazardous to human health. The exhaust system is designed to expel these gasses out the rear of the vehicle while reducing noise. If an exhaust leak occurs somewhere along the exhaust system, the gasses can seep into the interior vehicle cabin. This can be hazardous, or even fatal to vehicle passengers due to the buildup of carbon monoxide.

Performance Issues

The exhaust system piping is designed to optimize volumetric efficiency for the engine. Since the expulsion of exhaust gasses is necessary with every combustion cycle, the exhaust system must allow for an unrestricted flow of gasses for maximum engine efficiency. An exhaust leak creates air turbulence in the exhaust piping, and also throws off the volumetric tuning of the exhaust system. Both of these effects lead to diminished engine performance, both in horsepower production and fuel efficiency.

Exhaust Noise

A leak creates excess exhaust noise due to the escaping gasses. This tends to create an air hissing noise audible when in close proximity to the leak location. Additionally, you may experience excess engine noise and/or popping sounds originating from the exhaust leak. While excess noise is undesirable, it has the positive effect of allowing you to easily locate and diagnose exhaust leaks.

Checking for Exhaust Leaks

Exhaust leaks caused by large cracks, rusting and other extensive damage can be diagnosed by visually inspecting the exhaust piping and connections. When checking the exhaust, pay especially close attention to the welding, as these are the most likely locations to crack due to stress and heat. Also, ensure the exhaust hangers are all securely connected to the underside of the vehicle, as loose hangers may allow the exhaust to rattle against the chassis, leading to further damage. Finally, check that the flange bolts securing each piping segment are extremely tight. If you still experience exhaust leaks after inspecting the exhaust system and bolts, replace the exhaust gaskets located at each flange connection.

The throttle position sensor is an electronic sensor that plays an important role in assuring efficient engine operation. Without a properly functioning throttle position sensor, an automobile may experience a number of problems.

Purpose

The throttle position sensor measures and reports the amount of throttle opening to the engine control computer. The computer uses this information to make adjustments to the mixture of fuel and air used for combustion. As the throttle is opened, the engine requires more fuel in the mixture to provide needed power.

Problem Signs

When a throttle position sensor begins to fail, the engine will often hesitate during acceleration as the sensor is not properly reporting the change in the amount of throttle opening. A faulty throttle position sensor may also cause other problems including stalling, rough idle and an increase in fuel consumption.

Troubleshooting

Problems from the throttle position sensor often trigger a diagnostic fault code. A diagnostic code reader can be used to read the fault codes to locate the source of the problem. Before replacing the sensor, the sensors wiring should be inspected for damage or loose connections. The sensor may also become loose causing the readings to be inaccurate.