Sunday, February 27, 2011

The Jumping Off Point

This is the point where it either happens just as it should, doesn’t happen at all, or maybe just sort of happens in a way that is so insignificant that it hardly has an impact on anything. Either way it’s the point of no return. The jumping off point that I am talking about is the spark plug.

This is the place where the spark that ignites the air fuel mixture enters the combustion chamber. This is the last component in what’s known as the secondary ignition system. The energy that powers the wheels of the car originates in the gasoline, but if the spark does not meet up properly with the fuel and the air after they are already mixed, then the energy conversion known as combustion doesn’t occur. Or at least only partially occurs. Anything less than the best when it comes to combustion leads to low power, high emissions, and poor fuel economy.
Even though all spark plugs look the same they aren’t. Subtle differences in design change the way the spark jumps the gap. The spark must jump from the center electrode to the ground electrode, and it must do this with the cylinder under pressure. The gap is usually no bigger than about .060 inches, but the higher pressure in the cylinder requires the spark to jump the gap with a much higher voltage than what would be required if the cylinder was not under pressure. Secondary ignition system voltages usually run somewhere between 12,000 and 60,000 volts but can go higher under some circumstances.

The center electrode is generally made from a copper alloy, and in the old days this copper went all the way to the tip of the electrode. The spark would jump from the edge of this center electrode and not from the middle. The copper resistor spark plugs would have a tendency to wear out more quickly because the tip would get so hot it would burn away a tiny bit of metal every time the spark would jump. Newer spark plug electrodes use metals such as platinum or another metal related to platinum known as iridium. These metals resist the heat and corrosion caused by the spark and combustion and last much longer. Regular spark plugs wear out in about 30,000 miles but the platinum tipped plugs can last about 100,000 miles.

So what kind of spark plug should you put in your car when it comes time for some new ones? The answer here is very simple. Use the plugs that the car was designed to use. This doesn’t just apply to the design of the plug, but also to what brand to use. Many aftermarket spark plug manufacturers make spark plugs in all sorts of designs and with the proper dimensions and heat ranges to fit in just about any kind of engine; however, just because the plug fits in the hole, and the guy at the parts store said it was for your car, doesn’t mean that it’s the right plug.

Some of the original equipment spark plugs are made by companies such as AC Delco, Motorcraft, Champion, NGK, Bosch and Denso. These plugs are available at most aftermarket parts stores so there is no reason to put anything else into your car. The claims made by some parts companies regarding some special design that is supposed to give you more power, or better fuel economy don’t hold up. If you have modified your ignition system in same way then maybe you need something special but for the average car, stick with what it’s supposed to have.

The Auto Rules

Friday, February 25, 2011

Working with Dad

One of the reasons that I became an automotive technician was because I spent a lot of time working on cars with my father when I was a kid. I associated hanging out with dad in the garage with having a good time, and fixing cars is what we did; therefore, fixing cars was also a good time. Knowing the things that I know now about working on these silly machines, it makes me smile to think back on some of the things that my dad used to do out in the garage, not for any enjoyment on his part, but because he was usually too cheap to take it to a shop.

My father has a mind for mechanical things so he was always able to figure out what needed to be done to fix the car, and then he was able to nearly always figure out how to actually perform the repair. As a kid I thought he was amazing because he could fix anything. Looking back now I think he was amazing because he took the time and put forth the effort to bust his knuckles on some old piece of junk, so that he could save some money to spend on his kids. He also saved a lot of money over the years by only driving vehicles that required little or no monthly payment.

This meant that we had some terrible cars over the years, not all of them were completely awful at the time, but thinking back on them now there is not a single one of them that I would own, with the exception of maybe the old International Travelall 4X4. I don’t know for sure, but it was probably about a 1973. That thing was and maybe still is a beast worth having around. One of the vehicles he put his wife and kids into, that was a nice ride at the time, was an ‘85 Pontiac Parisienne station wagon. This was a nice ride but was cursed with the nasty old 5.7 L Oldsmobile diesel. The only thing good about that engine was the fuel economy. That motor was gutless, unreliable, and left us stranded in the mall parking lot more than once, because it wouldn’t start at temperatures below 50°. Lucky for us one day the engine came undone while my mom was driving around town on some errands.

Another thing that my dad liked to do was buy cars cheap for the purpose of fixing them up to resale them. I don’t know that he ever made much money doing this but my dad never made a lot of money doing anything. The thing that made him a solid bread winner was his persistence, combined with his frugality. Some of these cars were actually pretty decent cars, and were usually nicer than whatever he was driving or my mom was driving. I think there was more than once that he wished he could have kept one or two of them for the family. A few times he would actually register the car in his name and begin driving it legally (many times he would drive these cars around without license plates while fixing them up) as his daily driver only to succumb to the call of the money that the car would fetch from a sales listing in the classifieds. After that he was back to driving whatever old thing he could pick up for a few hundred dollars.

Some of the projects I remember that bring a smile to my face when I reflect upon them are things like the clutch job on the old ’66 Chevy pickup that he used to have. This is the truck that wouldn’t shut off when you turned the key switch off, it would stay running until you turned off the radio. That truck is one that on second thought goes into the category with the Travelall I mentioned previously. The task was simply to replace the clutch disc and pressure plate. I remember he had to heat up the bolts with a torch that held the cover on the inside of the cab around the shifter. He pulled one of the hot bolts out and set it on the Indian blanket seat cover, melting a hole in the cover shaped like the head of a bolt. He used to talk about how nice the rubber floor covering was in that truck but he ended up ripping it in a few spots during that job. This truck is also the one that he used, to teach me how ignition points work. If you don’t know what points are then ask someone who is very old.

One of the projects that makes me almost laugh out loud still to this day, was when he replaced the cam shaft in a then not too old, 1981 Chevy Citation. This is funny because he did it with almost no tools. He pulled the engine out with a come-along hung from the rafters of the garage. His hand tool selection consisted of a few 3/8 inch drive and 1/4 inch drive sockets, 3/8 ratchet (likely no 1/4 inch ratchet just the sockets with an adapter), some combination wrenches, a Phillips screwdriver, a flat screwdriver/mini pry bar, and a curved claw hammer. Many times that ratchet handle was met with the head of the hammer. With enough room to swing it, the hammer could make that poor little ratchet undo all sorts of tight bolts. I have no doubt that my father knew that this was not the ideal way to work on a car but had he spent the money to buy proper tools one of us kids might not have gotten some nice gifts that year for Christmas. Being a young kid and watching my dad work this way, I figured he knew exactly what he was doing.

One more memory of my father and his cars was from years much later, when I was a teenager. He had an old (there’s that word again referring to one of my father’s cars) Volkswagen Rabbit with a diesel that had to be push started on cold mornings. He would leave for work in this car about the same time I would leave for school. He had purchased my grandpa’s ’78 GMC pickup and had essentially given it to me to drive to school everyday and then to work in the afternoons. The truck was so much more reliable and better to drive but he let me have it. The thing I had to do each morning with the truck was push him down the street fast enough so that when he popped the clutch on the Rabbit, that little diesel would generate enough heat to get itself going. Once he was running he would head one direction and I would head another. One time he popped the clutch too early while he was still in contact with the front of the truck. The little rabbit bucked and pitched a few times and the bumper of the truck hit the tailgate of the rabbit. He just shrugged it off, didn’t worry about the body damage to his car, and told me to push him one more time.

These stories might be funny to me now but the thing that I really think of when I remember these times is that the things he did, he did for his family. Transportation was just that, he cared nothing about social status. Cheap transportation meant weekly repairs. If he got a bit of personal enjoyment out of fixing a car with his own two hands then that was okay too. The thing that he taught me while we were working on cars together was not how to replace a spark plug, but how to take care of a family. He has nicer cars now but there are still some stories associated with those that show he is still the same guy that he has always been. Thank goodness for that.

Wednesday, February 23, 2011

Computers and Multiplexing

Like everything else in our lives, computers are taking over the controls of everything on the modern automobile. How many computers does the average car contain? You might guess one or two but you would be wrong. Maybe you never even realized that cars had computers controlling everything. The most basic stripped down featureless car nowadays contains at least 4 or 5. One that controls the engine and/or transmission, one that controls, the instrumentation, one or two that control body related functions such as windows, doors, or even the dome light, and one that controls the airbag system, and so on. Very high end, feature filled cars could have 20 or more different control units all tied together in a network of control.
A typical engine control computer
Dome light you say, how and why is that controlled by a computer? Remember back in the old days when you would leave the car door open overnight only to find the battery drained the next morning? With a computer controlling the dome light it can time how long that door has been open, and after a reasonable amount of time it will shut the dome light off automatically. This saves the battery from excessive discharge so you can start the engine.

Don’t complicated computer controls just make things more likely to break, or more complicated to fix? The answer here is yes and no, not necessarily in that order. A system that is computer controlled might be complicated to fix but only if you don’t know what you are doing. Any good automotive technician needs to know how to fix every system on a vehicle regardless of how the systems work. If they know what they are doing then it doesn’t really matter how the system functions. On the other point, cars today are so much more reliable, even with computers on board, compared to what they used to be, that it’s just not reasonable to assume that complexity makes things break down more often.

All of these control units onboard each modern car or truck, are wired together in a network of control nodes, sharing information with each other. This data sharing scheme is referred to as multiplexing. This helps to simplify each individual control system because one sensor or input can be used to send information to multiple controllers. For example, back in the late 80’s and early 90’s when computer controls were becoming very popular but multiplexing had not yet hit the scene, some vehicles had 4 separate coolant temperature sensors. One sensor would tell the engine what the temperature was, one sensor would tell the temp gauge what kind of reading to display, one sensor would tell the cooling fan when to turn on, and one sensor would tell the transmission control unit what the engine temperature was. By sharing this data on a serial bus between control units, any system that’s interested in this information can take it or leave it. This means less wiring and fewer sensors. One sensor sends a signal to one controller and that controller puts that data out on the network.
Coolant temp sensor
 This sounds rather complex but it really isn’t once you know how it works. With computer controls there are so many new features that are possible, it’s simply a matter of thinking up new things to program into the system. So at what point are people going to figure out a way to upload a virus into this network? Theoretically it could be done but it’s not too much of a worry until all of our cars have access to the internet (which could come sooner than you think). The other issue preventing computer viruses from threatening our vehicle is that cars don’t run common operating systems like our home computers do. Operation programming can vary substantially from one make and model to another, and the auto manufacturers don’t share this coding information. Who knows what could happen in the future. Perhaps we will have more thing to be afraid of when we turn our vehicle over to a valet or a technician at a quick lube joint. 

Monday, February 21, 2011

My Rides

Just a few words about the vehicles that I drive. If you want to know what a person is like you can tell a lot by looking at what they drive. Considering that the automobile is a direct reflection of personal preferences, lifestyle, and of course status, looking at what’s in the garage correlates with what’s in one’s mind, heart or bank account. This rule doesn’t always apply but it does most of the time.

My daily driver is a 1993 Toyota Land Cruiser. I have had this one for about 7 years now. During the summer months it sees more dirt roads and two tracks then it does pavement. This vehicle is not modified at all but it is still an excellent off-roader. This rig has a 4.5 liter I6 with 24 valves and DOHC. During the winter time this vehicle handles extremely well in snow because it is always in 4WD and it has ABS. Toyota Land Cruisers are tough and the proof is in the fact that it has a live front axle and a full floating rear axle. This thing has been off road a lot and it never gives me any problems. There is plenty of room inside for my kids and all of the stuff we take with us on our adventures since it does seat 8 (not that I have 6 kids). I think that I might have this vehicle forever. I don’t care that it’s old, since it’s not too old, by too old I mean it’s not so old that it’s carbureted, or really gutless like some of the Land Cruisers that are little older than mine.

The wife’s daily driver is a 1999 Honda Odyssey. Now aren’t we just stereotypical. The husband rolls in an SUV while the wife shuttles kids in the minivan. First of all I want to say that my wife loves her minivan and couldn’t ask for anything more. Someday she could probably do with a newer one, but she loves the van that she now drives. She used to drive the Land Cruiser as her daily driver, but she loves the minivan so much more. The van is very nice for what she’s got going on in her life each day. With features like power sliding doors, a rear seat that folds into the floor, climate control, and a great 3.5 liter V6, this vehicle suits the family very well. We have had this thing for about 2 years and it has given us zero trouble.

The third vehicle is a 1995 Ford F250 4X4. We have this truck around for all the things that a pickup is great for. We use to go to the home improvement store, haul a load of junk to the dump, or for picking up a load of top soil. This truck is pretty amazing with 307,000 miles on the original engine. It still runs well but it does have a host of little problems that I am too lazy to fix. For our purposes though the truck works great as it is, and I have done a lot work on it to make it run well and drive down the road in a half way decent manner. Being an automotive technician I know which problems to fix right away and which problems to ignore. The other reason that we have this truck is because we live in a place where anyone who’s anyone has a truck.

So what does owning these three vehicles mean? Who knows, but it could be significant. Someday maybe I will write about vehicles that I have had in the past. There is so much to say about that subject as well.

Sunday, February 20, 2011

One Trick Pony

Some say that an automotive technician needs to know all kind of things in order to fix the modern automobile. Being proficient in things mechanical and knowing how to turn a wrench is not enough anymore. An effective automotive technician must have skills in the worlds of electricity, electronics and computer control systems with network communications, hydraulics, refrigeration, chemistry and the laws of thermodynamics, and all sorts of other things. The problem here is that even the best automotive technician never becomes an expert in any of these things. You could say however, that the auto tech doesn’t know everything about anything, but knows something about everything.

I have been an automotive technician officially for about the last 12 years, but I have been working on cars my whole life. In recent years I have been working as an instructor of automotive technology at a small community college. Sometimes I think that working on or around cars is the only thing that I have ever done. I am a one trick pony. I am the automotive technician who knows a few things about a lot of things but I don’t know everything about anything. Most of the time I act like I know everything about everything, maybe because I’m a normal guy, or maybe because I’m a bit of a jerk. In reality I know enough to start a conversation and then develop it to the point where I can fully, and with great force, stick my foot into my mouth.

I really enjoy everything about the automobile. I also like just about every kind of car or truck that there is. Many of them I would never choose to own because while I may like just about all of them for one reason or another, I know which ones are more likely to cause me problems. This area can be controversial and I know that I have more than once made a comment about some ‘piece of junk car’ that just happened to be owned by a friend who heard what I had to say about it. While it’s easy to say which cars are the best, fastest, or most reliable, when you start to pick which cars are the worst of all time, the topic can be a bit heated. Nevertheless, I can’t totally hate even the cars that I determine to be junk because the fact of the matter is, these substandard cars have helped me support my family over the years.

I like cars that are old. I like cars that are new. I like cars that use the latest technology. I like cars that have nothing in them even close to the latest technology. I like cars that are fast and get horrible gas mileage. I like cars that are slow but get 70 miles per gallon. I like cars that are big, and I like cars that are small. I love a car that is very practical but I can also throw practicality out the window for no good reason. Every car ever built was built to fill a need somewhere and there are very few that have no purpose at all. I can usually think of something to say about nearly every car on the road.

The purpose of this blog is to give me a place where I can talk about things that I know something about or at least give me a place to talk about things that I pretend to know something about. I will mix in some facts and figures, but there may also be a fair amount of opinion found among the various things that are posted. I will primarily talk about things that interest me but I may also discuss things that relate to current events in the automotive world. Regardless of what I write about, I know that at least my mom will log on once in awhile, and if I’m really lucky then my wife may read a few posts now and then as well.

The auto rules.