ASE automotive electrical test 09/12/2010
It is time for me to take my ASE automotive electrical test again. Every five years we are required to re certify in each individual area. To me the automotive electrical test is one of the more difficult to pass.  25 years of auto repair Even though I have more than 25 years experience and this will be the sixth time I will be taking the test I still find it difficult to pass. The weird part is that when it comes to diagnosis and repair this is one of my strongest areas of the automobile. One reason for this is that the ASE automotive electrical test is very heavy on theory. An understanding of ohms law and other basic electrical and electronic knowledge is required to answer individual test questions that appear on both the re-certification test and the full-blown 55 question test. Add Comment Logical Car Diagnosis 08/24/2010
How logical diagnosis reveals car problems. Most car mechanics will perform a good visual inspection of the suspected problem areas before they formulate a plan of attack. Often this first step will uncover damage that is causing the complaint.  Car Mechanic An example of this is a key wiring harness chewed through by a rat. Small rodents seem to love the taste of wiring. They also find the warm engine compartment a nice place to build a home. These visitors can do a lot of damage in a short period of time. Performing a quick visual inspection may reveal signs of one of these engine compartment pets. Sticks, leaves and branches along with other debris that you would not usually see in an engine compartment such as pieces of bread or trash is a tell tale sign that a rodent has visited. In some cases you may also see tiny pieces of plastic from wiring conduit or colored pieces of insulation mixed into this debris. Engine ping and knock sensors 08/14/2010
The knock sensors purpose is to protect the engine from pre-ignition or engine ping. When this sensor malfunctions or provides a false positive it can cause car problems such as poor performance and bad gas mileage. Let’s review how the knock sensor works and how to test it.  Knock Sensor Sometimes it's not easy to find the root cause of an engine ping problem. When the pinging is coupled with a check engine light it actually makes the diagnosis much easier. With pre-ignition valve clatter in conjunction with a set computer code of P0325 this will lead you in the direction of the knock sensor.
The knock sensor is used to back off ignition timing when the engine is experiencing a knocking or pinging noise. The sensor itself is calibrated to detect the vibrations that are unique to this type of engine condition. When it believes that it hears this noise it sends a command to the power train control module to retard the ignition timing. If the sensor malfunctions it does not always set a check engine light code. It will depend on the year make and model of the vehicle. Ignition engine misfire 08/06/2010
When your engine is running rough or you have a misfire condition the problem can be a fuel system malfunction. But more often than not I personally have found an ignition engine misfire to be more common than one that is related to the fuel system.  Fuel injectors Yes you can have a problem with a fuel injector that is either dirty or leaking. But in my opinion it's just not as common as finding a malfunction in the ignition system. Malfunctions such as a bad spark plug wire or even worn or fowled spark plugs seem to be a more common cause of a cylinder that is not firing correctly. Checking ignition related misfires
Cylinder Head Gasket 07/25/2010
The cylinder head gasket is probably one of the most important sealing components in the engine. One of the telltale signs when this gasket fails is that coolant will mix with the engine oil. When this happens the engine oil will turn to a milky color and a jelly like consistency. Often the more severe the leak the milkier the oil becomes.  Head Bolt Tightening Pattern One of the biggest causes of repeat repairs when a head gasket is replaced would be the procedure for tightening down the bolts was not followed correctly. Head bolts must be tightened in the correct order and to the proper amount of torque. Tightening sequences and specifications are available in your car service manual that will also include the step by step repair procedure for your model. Most cylinder heads are tightened in a sequence that starts in the middle and then moves out towards the ends. The bolts are generally tightened in two or three stages. If the final torque is 100 foot-pounds the bolt may first be tightened to 50 foot pounds all away around before the final specification is reached. Misfire codes and check engine lights 07/08/2010
The check engine light is turned on when an engine misfire is detected because unburned fuel pouring into the exhaust manifold will cause extremely high tailpipe emissions. Also if the situation continues raw fuel entering the catalytic converter can cause internal damage to the catalyst. This will also increase tailpipe emissions and will most likely lead to having to replace the catalytic converter which happens to be a very expensive part on most vehicles. For this reason computers can be very sensitive to engine misfires and illuminate the check engine light even if the problem is intermittent. Misfire monitors Crankshaft Sensor The onboard computer is capable of quite complicated misfire monitoring. The engine control module uses the crankshaft angle measurement to detect this misfire. It's actually quite amazing how it is performed. Click the read more button to see how it works.
Power Sunroof Problems 07/01/2010
Power sunroof problems reviewed. Many malfunctions in the sunroof system fall into 2 categories that can often be related to each-other. Water leak issues and electrical problems. Sometimes wiring or switch corrosion can be caused by the water leaks.  power sunroof A power sunroof can slide the roof panel open or closed. You can also tilt the roof panel up in the back to allow fresh air into the passenger compartment. When driving down the road this can also pull a vacuum and remove stale air from the interior cabin. In most cases power sunroofs are not that much different than electrically operated power window systems found in most automobiles. Many common parts are shared such as system relays, a master control switch and the motor assembly to perform the movement. Note that most power sunroof systems are protected by a circuit breaker instead of a fuse. This is in case the sunroof begins to bind. It protects the motor by opening the circuit breaker. Often when people have power sunroof problems they will begin to look for the fuse when there is actually none. A circuit breaker will reset automatically when it cools down. Car Power Seat Problems 06/15/2010
Repairing car power seat problems can sometimes be as simple as removing a penny from the seat track. Or they can be as complicated as having to test switches, relays and motors. Most power seats are not protected by a fuse but instead use a circuit breaker.  power seat switch Before we get into what to look for when your power seat is not working let's talk about why this issue is more common. Vehicles that are equipped with a power seat option are becoming much more common than they were just a few years ago. Where as they use to be exclusively deployed on luxury cars you can now find this popular option on even the most basic models. CV joints can cause car vibrations 05/07/2010
A common complaint from drivers and motorists would be car vibrations occurring at highway speeds. Most mechanics and myself included would first concentrate on tire problems and wheel balance.  driveshaft universal joint And this is definitely the most common cause of vibration complaints. But what do you do when you put on new tires and they balance out perfectly yet the vibration continues to exist on the vehicle. If the car is a front wheel drive automobile checking out the CV joints and the drive axles would seem to be the next logical step. If it is a rear wheel drive automobile universal joints and drive shafts should be inspected for problems. Often these different types of driveshaft components can create car vibrations that feel very much like tire balance issues. Cleaning Dirty Fuel Injectors 03/20/2010
Dirty fuel injectors have become a big selling point for popular fuel additives and gas companies. A few gas companies say that they add chemicals to their fuel that will help keep your injectors clean and make your engine run better.  Fuel Injection Cleaning Kit Some companies selling fuel injector cleaners state that they will increase fuel economy and restore engine power. All of the above statements may be true if you actually have dirty fuel injectors. Before you pay more at the pump for gas or go out and purchase additives and cleaning solutions it would be nice to determine if they are actually needed. Testing the flow rate and the efficiency of the injectors can not only be performed but can verify whether cleaning is necessary. I have more information on fuel injector testing on my you fix cars website. | Car Repair Help
CategoriesAll ArchivesJanuary 2012 |
RSS Feed
