Ironically, after the article I wrote about batteries last month, I was faced with a shuttle van that would not start. After a bit of embarrassment and a jump-start, I was on my way straight to our Express Lane. It was there that the battery tested good and more diagnostics needed to be performed to pin down the reason for the no-start. What else could be wrong? How do technicians figure these things out? Do they just hook up their magical scan tools and - volia! - the problem is revealed? Or is there more to it than meets the eye?
Every engine requires four basic ingredients to start: sufficient cranking speed, good compression, adequate ignition voltage and fuel. Any time your engine fails to start, you can assume it lacks one of these essential components. But which one? The answer is not always clear-cut, especially if the problem is intermittent, so it can be like finding a needle in a haystack.
Your no-start situation needs to be analyzed. What happens when you turn the key? Does the engine crank? No? Then you are probably dealing with an issue related to the starter or battery. If it does crank but refuses to start it lacks ignition, fuel or compression. The most prevalent cause in this case is a failed fuel pump. Generally speaking, these are the two separate tracks your technician will take when diagnosing your no-start problem. Let's explore each separately.
NO CRANK, NO START
Certainly a battery inspection is the first step, as we discussed last month. But if your battery is fine, there are more questions to ask. Has your starter been acting up, as evidenced by unusual noises or slow cranking? Is this the first time your car has failed to crank, or has it happened prior to this episode? Have you had the starter, battery or battery cables replaced recently? It could be a defective part or loose connection. If you've not had any parts replaced recently, there are other areas to look into.
Bad ignition switch The ignition switch is seldom the problem, but your mechanic will rule it out as part as the diagnosis.
Bad starter or connections Just as the corrosion of your battery connections can lead to no-start problems the same is true with corrosion of the starter. It can affect any electrical component, especially parts that are exposed to the elements. Your mechanic will test this with a circuit tester. If the starter spins freely when the key is turned, the problem lies elsewhere. If it does not, and all connections look good, the problem lies within the starter. To verify this, tests will be performed by your mechanic.
Alternator The alternator keeps the battery fully charged, providing the power needed to start your car. If there is a problem with it or the alternator belt, this could be the cause of your no-start so testing must be done.
Electrical problems There are many electrical components that may need to be checked if all other areas are exhausted in the no crank, no-start diagnosis. This intricate process can take more time for you and your mechanic.
CRANK BUT NO START
In this case, the ignition, fuel and compression components need to be examined.
Spark If the engine can't spark, there will be no fire. Spark is created by your vehicle's ignition system. If there is no spark, the condition of the spark plugs is considered. If they are all good, this is perhaps the most difficult no-start diagnosis. It can take a lot of time and experience and it's best left to a seasoned mechanic to narrow down the problem.
Fuel If you see a good spark when you crank the engine but it won't start, check the fuel system. As previously indicated, a fuel pump failure is the most common cause of a no-start problem with a crank. But there are other components to consider as well. There are many electrical connections within the fuel system that need to be checked to be sure they are tight. If all connections are tight and the fuel pump is working properly, the problem could be a clogged filter. How often do you replace your fuel filter? You should have it replaced every 12,000 miles. Replacing it in a timely fashion can help you avoid this problem.
Compression If your engine has spark and fuel, the problem is compression. If the charge of air and fuel cannot be compressed properly, the combustion process will not work like it should and your car will not start. There are several reasons for a lack of compression - all of which are more complicated than we have time or room for in this article.
The bottom line is, there is so much to consider when diagnosing a no-start problem. Be sure you relay as many details as you can to your mechanic to better enable him to narrow down the problem as quickly as possible, which will benefit both of you. Don't you love it when a solution to a problem is found quickly and when it's an inexpensive fix? I sure do! But sometimes this is not the case.
This summer I remodeled our bathroom. I hired out the plumbing and electrical, but I laid all of the tiles on the walls, floor and tub surround myself. As the colder weather has snuck up on us, I turned on my new heated floors only to discover an error message on the thermostat. Certainly it couldn't be a big deal, right? Wrong. I called the electrician and he went through a series of tests, discovering that a sensor was faulty. Guess where the sensor was? Yes, under the tile. It was such a bummer! But what could I do but accept the diagnosis? So I busted out some perfectly laid tiles, put in a new sensor and I am preparing to re-lay the new tiles.
We always want a simple, inexpensive solution that will make our lives easier, but it's not always possible. Life isn't simple and neither are vehicles. Problems arise when it's least convenient, that's why it great to be prepared with a mechanic you can trust to look into your problem when it's too difficult for you to do yourself.
By Jeana Babcock