<![CDATA[Online Auto Repair | Diy Car Repairs | Automobile Information

<![CDATA[Online Auto Repair | Diy Car Repairs | Automobile Information - Blog Auto Repair]]>Wed, 16 May 2012 10:34:48 -0800Weebly<![CDATA[Vehicle Speed Sensor Operation]]>Thu, 10 May 2012 13:45:16 -0800http://www.onlineautorepair.net/1/post/2012/05/vehicle-speed-sensor-operation.htmlThis article will cover vehicle speed sensor operation as I believe a better understanding of any individual component will help with diagnosing problems that may be related to that system. Since the recent search engine update this site ranks high for queries about vehicle speed sensors.

OEM VSS

Since I have learned to go with the flow when it comes to Internet traffic I also wrote an article that focuses more on vehicle speed sensor problems. But I still stand by the fact that understanding how this important component works will aid in diagnostics.

This sensor actually tells the computer vehicle speed in kilometers and miles per hour. Speed is an important input to many output controls such as torque converter clutch lock up and the proper flow of EGR gases. The information that is sent from speed sensor is used for other systems, such as cruise control, fuel and spark management that can have affects on fuel economy if the information from the component is incorrect.

Where is the VSS located?

Gear drive Speed Sensor

Earlier vSS were mounted in the speedometer cable and they looked more like an adapter because that's what they actually did. In the mid-80s speedometers were still run from a drive gear in the transmission up a cable to the speedometer head manually. But most today are mounted in the transmission or trans-axle (front drive) where the speedometer gear drive was located. These modern parts Use magnetizim to get precise readings.

On rear wheel drive trucks and cars you can also find this component mounted in the rear differential. On some models you will find more than one speed sensor. One located in the transmission that can provide information to the transmission module. And one mounted in the differential that will send signals to instrumentation such as the speedometer.

Although ABS braking systems use wheel speed sensors they often compare them to information received from the main VSS to make decisions about braking and wheel lock up. This is why I always recommend that you check a component location diagram and a good service manual. As cars have evolved from the mid-80s this is one component that has changed its form, capabilities and physical location over the years.

Diagnosing speed sensors

Magnetic vehicle speed sensor

Prior to the SS diagnosis the vehicle should be lifted on the hoist side of the drive wheels are free to rotate. If you back probe the output wire and connector voltmeter between it and ground and then start the engine you should find a .5 V reference signal a good way to determine a wiring problem as opposed to a vehicle speed sensor problem would be then to trace that wire up to the PCM and back probe it again.

You should find the same voltage at the PCM as you did directly at sensor. The internal resistance of the speed sensor can also be tested and compared with the manufacturer's specifications in the case of a true terminal sensor the resistance is measured across the two terminals. The typical range for a good component is anywhere from 800 to 1400 ohms of resistance. Again check your service manual for the exact specifications any readings outside of these parameters indicates that the part should be replaced.

Another method that is commonly used by technicians would be to have a scan tool connected to the vehicle diagnostic port. Specifically one that is capable of reading the data stream. The scan tool that I am recommending in a low price range (about 75 bucks) that is still capable of performing this operation is the Equus 3040 scan tool. With vehicle speed selected from the data stream you can wrote test the vehicle and have a partner monitor the speed and not only output volts but also miles per hour. Any sudden fluctuations or drops to zero can indicate a true problem exists in the system.

As time allows I will write additional helpful articles that cover the specific component. Until then you can head on back to the auto repair blog home page for more of the latest articles about auto repair.

]]><![CDATA[Cadillac V-8 Belt Diagram]]>Wed, 04 Apr 2012 13:20:00 -0800http://www.onlineautorepair.net/1/post/2012/04/cadillac-v-8-belt-diagram.htmlToday I am posting the belt diagram for the Cadillac V-8 specifically the 4.6 L engine. In the Cadillac world this engine is nicknamed the Northstar. From what I can tell this belt diagram will work on other Northstar series V-8 engines regardless of the displacement.

1993 Oldsmobile Aurora

For a very short period of time the Cadillac V-8 could be found in some Pontiac's, Buick's and Oldsmobile cars like the Oldsmobile Aurora as 4.0 L V-8. I happen to be a big fan of this engine because of its tremendous power to weight ratio. My first vivid memory of this engine was when it first came on the scene in 1993 installed as the only option on the brand-new Cadillac Allante. I have a full size picture of the Mary Kay Pink Cadillac below.

Without further delay here is your belt diagram for the Cadillac V-8 4.6 L Northstar engine. I hope you click the read more button and see why I like this engine and learn a little more about the history and future of it.

Cadillac V-8 belt diagram 4.6 L

Cadillac v8 belt diagram

Remember 93 was a time when engines produced tiny amounts of horsepower but this engine was pumping out nearly 300 hp and 315 foot pounds of torque from an extremely light weight all aluminum 90° V8 package.

2002 Eldorado ETC

I worked at a multi-franchise Pontiac Cadillac dealer at the time and remember my first ride in a Cadillac Allante. Mary Kay cosmetics was also big at the time and this car was also available in Mary Kay pink and was primarily a convertible two door sports car but you could get a removable hardtop option.

In 1995 to 4.6 L V-8 broke the 300 hp barrier and standard equipment in one of the most popular Cadillac of all times. This was the Eldorado ETC and the Seville STS which was a four-door version of the same car. This was the perfect platform for genuine wood grain trim and leather appointments. Cadillac was now producing cars that where pure luxury and a joy to drive.

2010 Cadillac Dts

The 4.6 L engine stayed around a while unchanged. In 2006 Northstar V8 Cadillac engine found its way into the Deville touring sedan. Better known too many as the DTS. I was surprised to see that Pauli D. from the Jersey shore drives a Cadillac DTS with the Northstar V-8 as his primary transportation. I believe Pauly D's car is a 2009 model year but I'm not sure on that.

The Northstar system as a standard stainless steel exhaust that can often last a lifetime of the vehicle as compared to a state mental system that is prone to ride out and need maintenance. Also a telltale sign on a Northstar equipped DTS is the Quad Tip exhaust. This is a very aggressive sporty look for a vehicle that might be confused for a grandma's car. But if this car is good enough for Pauly D it's good enough for me.

Mary Kay Pink Cadillac 93 Allante

It looks like the future of the Northstar is not good. The go to v8 engine is now the Super charged 6.0L GM v8 putting out 556 hp in the CTS-V. The 4.6L had a good run. Most engines are not in production this long!

If you are looking for belt diagrams for other popular engines this next link will take you back to the diagrams section from this page that has the Cadillac v-8 belt diagram. If you are looking for Timing belts I have a must read article about the availability of timing belt kits. For more stories and auto repair information this next link will take you back to the blog for online auto repair.

]]><![CDATA[Belt Diagram GM V6 3.6L]]>Mon, 12 Mar 2012 14:16:05 -0800http://www.onlineautorepair.net/1/post/2012/03/belt-diagram-gm-v6-36l.htmlToday I'm posting the engine belt diagram for the 3.6 L GM V-6 engines. This time it's personal because this is the option that I have in my 2009 Cadillac SRX. This happens to be the best engine I've ever owned.

2009 SRX Crossover

I don't say this lightly. Because of my advanced age I could be considered old school and really only have respect for V-8 engines. The 3.6 L GM V-6 engines even back in 2009 came in at a respectable 304 hp.

In 2012 they were able to massage another 4 hp out of this V-6 engine to boost the horsepower to 308 making it the most powerful standard engine in a crossover. Considering the 6.6 L 400 cubic inch engine in my Pontiac T/A produced about 275 hp at double the weight you can't help but be impressed with General Motors version of this all aluminum V-6 engine.

Engine belt diagram GM V-6 3.6 L

Belt Diagram GM V6 3.6L

This belt diagram is not the best picture but I'm sure that you'll be able to determine how to route the belt from it. It was actually a snapshot I took of the owner's manual page they came with the car. What is interesting is that they are using separate belts for the alternator and water pump and the compressor and power steering pump.

Although the belt diagram was taken from my Cadillac owner’s manual, the routing is the same on other vehicles that General Motors installed this option into. And there is quite a healthy list of vehicles that use this engine as a standard equipment options. Including the now departed Pontiac and Saturn line of automobiles.

3.6L GM V6 Engine

To mention a few more of the many different models we can start with the Buick Lacrosse and the Rendezvous. We can move on to the Chevy line and include the Malibu, Impala and of course the mighty Camaro where the GM V-6 3.6 L engine is capable of putting out 323 hp in 2012 in the LT model Camaro.

Although this same design engine had been around as a 2.8 L for many years it became a 3.6 L in 2004 when it was installed in a Cadillac CTS as the standard equipment engine. Back then it was only in the 260 hp range. When they added variable valve timing and direct injection they were easily able to push this horsepower well above 300 horses.

The power and weight ratio of this engine is truly a design marvel. The block of the 3.6L is said to be thick enough to be punched out to a maximum of 4.0 L. This would allow room for evolution of this platform that someday may be the largest GM engine offered?

Don't quote me on this but I heard that the 3.6 engine is in the all-time top 10 engines list as far as horsepower to weight ratio along with many other criteria such as longevity and serviceability. So I posted this engine belt diagram for the GM V-6 3.6 L engine because if you own one of these motors you will probably have to install several serpentine belts on it before it goes to the junk yard.

If you're looking for another popular General Motors of V-6 engine I have the 4.3 L Chevy V6 belt diagram also available here. And for a list of all of my posted belt diagrams you can head back to the main page for engine belt diagrams. Or return to the homepage for the online auto repair blog.

]]><![CDATA[The 4.3 L Chevy Engine]]>Tue, 07 Feb 2012 10:40:13 -0800http://www.onlineautorepair.net/1/post/2012/02/the-43-l-chevy-engine.htmlIf you must have a 6cyl the 4.3 L Chevy engine is a good one to get stuck with. I mean this from a strength and durability aspect as opposed to efficiency. I have a long-standing relationship with this V-6 engine.

4.3L Mercruiser

The first year that I turned wrenches professionally was 1984. The 4.3 L v6 was installed in all kinds of vehicles at that time. Some notable vehicles would be the Monte Carlo and Buick regal and many other full size 80s General Motors cars. Even cars that were too big and heavy for the engine like the Caprice could be found with this V6 option installed. I remember popping the hood on a 1987 Chevrolet Caprice and seeing such a small engine in the big car.

I was thrilled how easy it was to work on with plenty of room all around the engine bay area. Not only did I have a vortec 4.3 L V-6 Chevy engine in my 2004 Chevrolet Blazer but I also had one of these in my boat. This was a carburetor Mercruiser version of the popular Chevrolet V6. The longer this engine was out the more horsepower it produced over the years.

It was 165 hp in 1984. In my boat (1988 Four Winns) it was rated at 175 horse power. The 2004 Chevy Blazer was one of the last years you can get this engine and it produced 220 hp. As I hinted at above these engines were solid but they were not known for their efficiency or trouble free operation. In my 2004 ZR two Blazer this engine pulled in about 12 to 14 miles per gallon. In 2008 when gas prices hit around five bucks this was one expensive truck to drive.

Problems with 4.3 L Chevy engine

4.3L Timing cover leak

Although the engine is sturdy and I have seen many of them go well over 200,000 miles of outstanding service, most of them needed some kind of work at one time. The kind of work it would need would often correlate with the year the engine was built. In 1993 when they went to the vortex version they installed a fuel injector known as a central port injector that was troublesome. In fact the CPI would often need to be replaced.

On my Blazer the 4.3 L engine sported an updated plastic timing cover. This became a problem and needed to be replaced and resealed just after the three year warranty had expired. This was a Big Job for the driveway! I had worked on many of these engines that still had the metal timing covers and I never saw one leak. And now that it's made of plastic I don't think I have ever seen one completely dry.

04 Chevrolet V-6 Engine

There were also several years when 4.3L V6 optioned vehicles had problems with corrosion buildup in the distributor. There was a little screen in the base plate of the distributor that would become clogged. This would trap moisture inside and you would often get corroded connections to the ignition module causing an intermittent stall or no start condition. This moisture also caused corrosion to build up on the inside spark plug wire contacts. A technical service bulletin was issued to make sure that the screen was clear.

The 4.3 L Chevy V-6 engine in my boat was always having problems. I replaced the starter motor and the alternator the second day I owned it. This is not really a fair test because the boat was used in the worst conditions possible. This would be the salty water of the South Florida gulf. Don't get me wrong I had a lot of fun but it was also a lot of work. But in the true fashion of this reliable V6 engine it always got me home so that I could spend more money on it.

So if you're stuck with a V6 engine the 4.3 L Chevrolet engine may make you angry a lot of days. It may cost you more fuel to operate it. Depending on the year of your engine it may leave spots in the driveway and cry like a baby for new parts. But the good news is that this engine is so strong that it will make you sorry you owned it for years and years to come. That last sentence was meant as a goodhearted poke at the 4.3 L Chevy engine that I do remember fondly.

Do you need a belt diagrams for the 4.3 liter Chevy? Or you can return to the homepage to read more stories from the blog for online auto repair.

]]><![CDATA[Weird Engine Flywheel Problems]]>Tue, 10 Jan 2012 14:50:05 -0800http://www.onlineautorepair.net/1/post/2012/01/weird-engine-flywheel-problems.htmlIt's not often you see engine flywheel problems. But when you do this usually means the vehicle is not going to move anywhere. Whether it’s a worn out ring gear causing a no start or a clutch problem the vehicle is staying put.

Picture 98 ford f150 with manual transmission

95 Ford F150

Sometimes we see rear main seal leaks work their way onto the flywheel surface causing a slipping problem. But the other day I stumbled onto a good one you don't see every day. How about an engine flywheel problem that caused slipping of a newly installed clutch.

I was called over to a friend’s house to see what went wrong with his clutch installation side job on his 95 Ford F150 pickup. He installed a complete clutch kit and had the flywheel resurfaced at a machine shop. The truck would move forward slightly when the clutch was let out but it was clear that it was slipping badly with all new parts.

engine flywheel

Unfortunately for diagnosis it had to come back apart. As in removing the transmission, which is no fun in the driveway. When we pulled the transmission out I didn't see anything wrong. We pulled off the clutch and pressure plate and you could see that the resurfaced engine flywheel was already starting to get a purplish color from the slipping clutch.

To make a long story short I truly did get lucky on this one as the cut or resurfaced job on the face of the flywheel didn't look so good. So we pulled it off and I went and got my micrometer to measure the flywheel. The flywheel was resurfaced in excess. Meaning that the flywheel was well undersized and needed to be replaced. The vehicle owner was not notified by the machine shop and wasted a lot of time and money on his driveway clutch replacement project.

When it comes to clutches and manual transmissions there are not a lot of articles or information on the Internet about the subject overall, compared to other automotive systems. This is why I have built a complete section over at my you fix cars website that talks about manual transmissions and clutches.

_More about the engine flywheel

Flywheel ring gear

The flywheel is an important part of the engine. It is also the main driving member of the clutch in a manual transmission set up. An engine flywheel is normally made of modular cast-iron which means that it is one of the heavier parts on the automobile. Another important component that sometimes causes problems is the ring gear that is pressed onto the outside diameter of the flywheel.

This is the area that the starter drive meshes with to turn the engine over during the engine start cycle. When a grinding sound is heard when the key is turned this is the starter drive grinding away at the ring gear of the flywheel. This grinding sound is not a good thing. If this happens many times you will probably have an engine flywheel problem and replacement of just the starter will not solve it.

Pressure plate and clutch

In this situation replacing the two components involved being the starter motor and the flywheel is usually recommended and in the end necessary. The rear surface of the flywheel is a friction surface machined very flat to ensure a smooth clutch engagement. As in the above example the flywheel itself can cause a few problems. If it is undersized the clutch will slip. If the surface is wavy you will have a clutch pedal pulsation and increased wear of the clutch disc.

The engine flywheel also provides some absorption of torsional vibrations from the crankshaft. Which is a fancy way of saying that it helps smooth out the engine as it spins it further provides some inertia to help rotate the crankshaft through the four strokes of engine operation.

There is a precision bore at the center of the flywheel that holds the pilot bushing this supports the front end of the transmission input shaft and maintains proper alignment with the engine crankshaft. Sometimes the pilot bushing is a brass insert and sometimes it is a needle bearing set up instead. Excessive vibration in the drive-line can cause problems in this area.

If you need more information about engine flywheel problems you can visit my page about what to do when having automotive clutch problems. For more articles posted here on this website is next link will take you back to the online auto repair blog.

]]><![CDATA[A bad starting safety switch]]>Wed, 07 Dec 2011 13:01:38 -0800http://www.onlineautorepair.net/1/post/2011/12/a-bad-starting-safety-switch.htmlIt's been a long time since I've seen a bad starting safety switch on a vehicle. But today I have seen one on an older Nissan 300ZX, a 1989 300ZX to be exact. I call it the starting safety switch but often this part is called the neutral safety switch.

neutral safety switch

It is a normally open switch that prevents the starter from operating when the transmission is in any other gear except park or neutral. This eliminates the possibility of a situation that could make the vehicle move forward unexpectedly or in reverse as well.

These starting safety switches or neutral safety switch whichever you want to call it are more commonly used with automatic transmissions but in this case of the 89 Z it was a manual transmission vehicle.

I am familiar with the Nissan ZX as I owned a 1988 model. In fact I have written quite a bit about my Nissan 300ZX problems. And although I had a lot of problems with my little sports car this was not one of them. I had to find the component location diagram and verify the color of the wires to properly by pass and test the switch.

_Where to find the safety switch

Neutral safety switches

Neutral safety switches can be located in either of two places within the circuit. One location is between the ignition switch and a relay or solenoid. When it is located in this position the safety switch must be closed before current can flow to the relay or the starter solenoid.

Sometimes the location of the neutral safety switch is between the relay and ground. Same as in the first position the safety switch must be closed before current can flow from the relay to a grounding location. When the relay has a ground it lets current flow to the starter solenoid and therefore engages the starter into the teeth of the flywheel.

The starter safety switch can also be used with an automatic transmission and can be electrical or a mechanical device. Sometimes these switches are mounted near a shift selector or on the transmission housing near the linkage. Often the switch contacts are wired in series with the control circuit so that no current can flow throughout the starting system unless the transmission is in neutral or park.

Although I have never seen them I hear on some Asian and German vehicles mechanical safety switches can also be used. Mechanical safety switches for automatic transmissions are simply devices that physically block the movement of the ignition key when the transmission is in gear. The ignition key can only be moved if the shift selector isn't park or neutral.

_Testing safety switch on Nissan

old neutral safety switch

The neutral safety switch on a late 80s Nissan 300ZX is mounted on the outer case of the transmission. But I did not go straight for this component because there is another safety switch mounted on the clutch pedal. Since this switch is easy to gain access to I tested that one first. Both of these switches are easy to test because it is a simple two wire circuit that is completed by the movement of the clutch pedal.

I used my automotive meter to check for continuity and the test passed so I moved on to the starter safety switch mounted on the transmission. When I pulled the wires off the starter safety switch and verify that the vehicle parking brake was set in the wheels blocked and further verified that the vehicle was in the neutral position for gear selection. I jumped the safety switch for testing only and was able to start the vehicle.

At this point I knew that the neutral safety switch was bad but when I pulled it out physically unscrewed it from the transmission I could see that the mechanical part of the switch was damaged. For some reason the owner of the vehicle decided to go to the junkyard and purchased a used part.

I urged him to find out if a new one was available aftermarket through a parts supplier. On Amazon a new safety switch for old Nisan's is about 10 bucks. Note that on some models the replacement parts are a lot more. For more of the latest articles this next link take you back to the blog for auto repair. There you can browse through older stories related to car repairs.

]]><![CDATA[Why Find a Cheap Service Manual]]>Wed, 09 Nov 2011 13:22:17 -0800http://www.onlineautorepair.net/1/post/2011/11/why-find-a-cheap-service-manual.htmlI am going to give it one more shot at convincing people that a service manual can be worth the $12 it costs to gain access to it. I totally understand that these are bad economic times. But there are some occasions when spending a few dollars can save many more.

Wire diagram from service manual Picture

service manual diagram

I know how it feels to be broke. When the economy crashed in 2008 I was not immediately affected. But now that we are at the end of 2011 I am totally engulfed in the destruction that the crashing economy has caused. I purchased (what I thought was) an affordable home in 2007. It was the cheapest house in town (and crappie). I paid 185K and put 20k into it to make it livable. Now I have abandoned houses on both sides and the house is valued at $55,000. I know what it's like to be underwater.

So when people send me questions and I tell them they should find a cheap service manual they e-mail me back and say... what "do you think I'm rich". I say it's only $12 and they say if I had $12 I could buy a new car. I then tell them that if I had to do this specific repair that I would find a service manual to follow. If I didn't follow the service manual I could do damage to the vehicle and extend the repair time.

This is why car repair manuals can often be much more valuable than the money it costs to secure access to it. When it comes to things going wrong on automobiles chances are someone has experienced the same exact problem and fixed it several times. More often it will be a professional mechanic that works on that particular model vehicle often dealership technician) that will be the first one to put it down in writing.

Yes there is a chance that you can go on the Internet and browse through different automotive forums and find the answers. But when it comes to fixing the vehicle it is hard to beat the information that originates from the factory. The service manual for your vehicle has extremely efficient diagnostic charts for solving many car problems.

When the diagnosis has pinpointed a failed component this very same service manual can provide instructions on how find (component location diagrams, part numbers, average costs, repair time) and replace that specific part. With diagnosis and repair procedures available in one location it really is hard to beat these reference materials that have been specifically prepared for your individual make and model.

Service manuals are inexpensive

step by step repair procedure

A lot of people go to the Internet to find the information they need for free. I don't blame you for trying and if luck is on your side you may find exactly what you need at no cost. But when the information that you need and more is available for cheap, you should set a time limit when it comes to searching the web for free service information. I don't care who you are, time is money.

The price that we put on our time varies with the individual. Some lawyers feel that their time is worth $487 an hour. Others feel that their time is worth eight dollars an hour. If your time is worth eight dollars an hour spending two hours on the Internet trying to find a service manual for free has eclipsed the $12 it would cost to buy the professional factory version.

I know how you feel when $12 is a lot of money. In my town unemployment is around 25% and you can get a pizza for under $10. When faced with the decision of whether to get a pizza or an auto repair manual as long as your car is still driving you will probably choose the pizza. Just remember that if you can't find the information that you need to fix your car for free then it is available at a reasonable cost.

When it comes to free information I provide a lot of it on this website. I have drive belt diagrams for free that are very popular. The problem is that it may not be the stuff that you are looking for. But just in case it is this next link will take you to the blog homepage for online auto repair. There you can see the most recent articles and see if the information can help you out or not.

]]><![CDATA[Where to Get Tires Cheap]]>Mon, 10 Oct 2011 14:14:11 -0800http://www.onlineautorepair.net/1/post/2011/10/where-to-get-tires-cheap.htmlYou already know where to get tires cheap but may be hesitant to give it a try. I know how you feel because I finally made my first tire purchase online. It just seems easier going to a local tire store and put on what they have in stock.

09 Cadillac SRX

What pushed me over the edge was nobody in town had matching tires for my 2009 Cadillac SRX in stock ready to go. When they tried to hard sell me into bogus house brand with all kinds of extras like a lifetime alignment package, I wrote an article about getting tire estimates and what to look out for.

Since my vehicle only needed two tires I wanted to match the ones that I would be keeping on the vehicle. Even though they where a popular Goodyear Eagle model tires the size was a bit odd and no one in town could get them quickly. When I got price quotes I was shocked at the cost and the wait time.

We know where to get cheap tires online. The Tire Rack runs ads on TV and is probably the most popular site in operation when it comes to getting tires online. A quick side note: I wrote a popular article a couple months ago about how to know when to replace tires it can shed some light on tire replacement.

See the newest tires at Tire Rack.

How to buy tires online

Cadillac Crossover Vehicle

The first thing to do when you get to the tire rack site is put your cars in the online garage. I selected my year make and model car and tire sizes this created an account. It took about five minutes to complete and was the hardest part of the process. I probably wouldn't have even gone through the account set up if I wasn't sure I was going to make a purchase.

After that was done I clicked on my garage and picked the rear tires for my Cadillac verifying that they had the correct size on file. Note that if you're not sure about your tire size I recommend that you check the doorjamb of your vehicle or the owners manual. This provides the factory original size and speed rating.

We all want to get cheap tires but, it's highly recommended that you stick with the factory installed sizes to maintain the vehicles handling characteristics. A lot of times when you get tires cheap they will be a different speed rating. Lower speed ratings have softer side walls and can feel very different on your vehicle.

Especially when you are talking about emergency avoidance maneuvers. This could be described as yanking on the steering wheel at highway speeds to avoid something. A lower speed rated tire will flex and make the vehicle slower to respond to the movements of the steering wheel. This is where tire rack shines.

You can do your research on tire pricing and not only get the feedback of other automotive consumers but also from the tire rack test track. In my case after I selected my tire size I was provided with 12 different choices. I decided to stick with the factory installed option which was the Goodyear Eagle because I was matching the front tires that did not need replacing.

Cadillac tires

I was tempted to switch to the continental brand that did receive good ratings and was less expensive but I would've had to purchase all four tires to be happy. Since this was my first time buying tires online I wasn't sure what to expect as far as delivery and installation. This is where I was the most pleasantly surprised about the service that they offered. I ordered the tires on a Monday and I received them on a Wednesday.

The two tires were strapped together and had a shipping label clear taped on, they were not boxed. The very next day being a Thursday I took them to my local Firestone and they installed these tires at a special price. When I say special price I'm referring to the deal that the tire rack online website has with local vendors like Firestone and Goodyear.

The stem and balancing package is a few dollars cheaper than if you went in there with tires that you got off of let's say eBay or something like that. My timing was good and I was done with the tire installation in about a half hour. Note that I have become a tire rack affiliate and could get paid if you buy tires from a link on this page.

But I did save money on the tires and got exactly what I wanted and the installation process couldn't have gone any smoother. Will your results vary if you try to get cheap tires online? Yes they could, but you will never know unless you try it out for yourself. So the next time you are looking for tires give the online option a try. This next link takes you back to the homepage for the online auto repair blog.

Do not buy tires from this link! ( I could get 4%)

]]><![CDATA[Spark plug gap problems]]>Sat, 10 Sep 2011 09:52:46 -0800http://www.onlineautorepair.net/1/post/2011/09/spark-plug-gap-problems.htmlA good question about spark plug gap from a site visitor. He was replacing spark plugs on his Toyota vehicle and noticed that the plugs he was removing had a much larger gap than the plugs he was installing.

spark plug gap

The difference in gap was so drastic that he thought may be something was wrong, or he had received the wrong replacement spark plugs. The Gentleman decided to buy the correct automotive special tool and gap them as stated in the service manual.

His e-mail question was why the distance was so large on the old plugs that he removed and so small on the new ones. On his vehicle the spark-plugs last 100,000 miles. In that time the center electrode or the tip of the spark plug wears and a large gap is created. After 10 years 100,000 miles this can be noticeable even with the naked eye. Also not all new plugs are gapped correctly at the factory or can change during shipping.

How to Gap spark plugs

Gap measuring tool

Both new and use spark-plug should have their air gaps not only checked but set the precise manufacturers specifications. On some vehicles the spark plug gap is included on a tag that is often applied to the radiator shroud or sometimes on the inside of the hood. This is also where the size of the engine and the model year are also indicated.

Some manufacturers especially in the case of Toyota provide the spark plug gap in the owner’s manual. On other vehicles you may have to purchase an auto repair manual to achieve the specifications. Mechanics both driveway and professional should use a spark plug adjusting tool.

gap adjuster tool

This is an inexpensive tool specifically designed to measure the gap between the electrode and the ground strap and also to make adjustments to that air space. These tools are especially designed to perform these adjustments without damaging the spark plug.

I have seen mechanics use screwdrivers and tapping hammers to make these adjustments. Although you can get lucky with this procedure is recommended to spend a few dollars to get the proper tool. This could save you time in the long run.

Always check the air gap of a new spark-plug before installing it. Never assume the gap is correct just because the spark plug is new. Although it might be tempting you should never try to reduce the plugs air gap by tapping it on the ground or hard surface. Try to make small adjustments and check it often. The ground strap is made of a soft material and can be adjusted easier than people think but you do not want to go back and forth more than needed.

Non-adjustable sparkplugs

Some engines are equipped with sparkplugs that have more than one ground strap or electrode. The gap between the center electrodes in each ground strap should be checked. If the gap between the center electrode and one of the straps is less than the others the spark will occur at the smallest gap.

This is also true of the V-shaped ground strap plugs that have become popular aftermarket replacements in recent years. There are also ring fire type plugs that jump from the center to the edge. This is sometimes known as a surface gap and the electrode cannot be adjusted with conventional tools and therefore most manufacturers recommend that the gap be left alone.

Replacing spark plugs has always been a favorite of do-it-yourself driveway mechanics. On some vehicles it is just as easy to replace spark plugs as it was years ago. On other vehicles it has become extremely difficult and should only be done by a professional technician. A good way to determine the difference is to review the procedure in the service manual and decide whether it's within your skill level. For more articles this next link will take you back to the blog about auto repair.

]]><![CDATA[Direct injection fuel delivery]]>Tue, 09 Aug 2011 10:29:34 -0800http://www.onlineautorepair.net/1/post/2011/08/direct-injection-fuel-delivery.htmlGasoline direct injection, how it works and why we need it. The GDI type of fuel delivery system is one of the latest waves in fuel management deployed on new model vehicles. This technology is what many car designers believe can help them achieve demanding corporate average fuel economy numbers while reducing tailpipe emissions and greenhouse gasses.

Direct Injector

Recently it was in the news that average fuel economy will be 54.5 miles per gallon by the year 2025. Each time the C.A.F.E. goes up car makers respond by pushing their fuel injection technology to the next level. In the 80s car makers abandoned the carburetor for fuel injection systems.

The first type to come on the scene was called throttle body injected and where more like a carburetor then the modern fuel injection systems. As emissions standards got tighter car-makers developed Port technology that was much more efficient. Gasoline direct injection takes this to a new level.

GDI is not new technology

Direct injection has been around for many years on diesel engines. With this type of fuel delivery the gasoline is injected directly into the combustion chamber. To do this specially designed injectors shoot the fuel into the high pressures and extremely high temperatures that exists as the cylinder comes up to be fired.

To prevent the heat from igniting the fuel in the line these injectors are designed to quickly and completely seal after the fuel is sprayed. They must also be able to spray with pinpoint accuracy at these increased pressures. If this did not happen the fuel would not enter the cylinder or overcome the compression that was building in the combustion chamber.

Advantage of injecting gas direct

The direct injection fuel delivery system allows for very lean operation at cruising speeds. When operating under heavy loads the GDI can provide the needed increase in the air fuel mixture by means of high speed computer controls that are now available at much lower prices. Being able to run at such a lean ratio at cruising speed or highway conditions can increase fuel economy on average by as much as 40% while decreasing emission levels.

Spraying the fuel directly into the cylinder also increases the volumetric efficiency because the intake manifold only delivers air to all cylinders. In the past with multi port, vortec or CPI (central port injected) the air and fuel was mixed in the intake manifold and swirled as it entered the combustion chamber. With GDI it can be injected on demand as needed.

Fuel Pump

One of the more interesting things about a direct injection fuel delivery system is the fuel pressure itself. It is highly pressurized typically between 500 and 1500 PSI when it is sprayed into the cylinders. Just 20 years ago when automobiles still used carburetors the fuel system was only pressurized to about 6 PSI. When F.I. came on the scene they bumped it up to about 35 PSI.

The 1500 pounds per square inch that is used in the direct injection delivery system is similar to the pressures that diesel engines use. Under this massive pressure the fuel charge arrives as a vapor. The injectors release a relatively small perfectly shaped spray of fuel around the sparkplug just before it ignites. This means only the area around the sparkplug has air and fuel to trigger combustion.

For more information about diagnosing problems with cars visit the online auto repair homepage. For more of the latest automotive technology articles like this one visit the blog for diy car repair.

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