Wednesday, 21 May 2014

Why a car won't start troubleshooting tips.

Why a car won't start troubleshooting tips.

Car won't start
It is frustrating when your car won't start. You are turning the key and... nothing happens. Almost every car owner has experienced this. 
There are many things that can go wrong with your car, but no need to worry, there is a solution for almost every problem.
Of course, you can call your local automobile association or a towing service and have your car towed to a local repair shop, but if you want to know why it doesn't start, read further. 
The process that goes on from the moment you put the key into the ignition to the point where the engine is running involves a few steps. Once you know at which step things go wrong, you will have a better idea why your car won't start and what to do.
Answer these questions; if the answer has a link, follow it; if not, continue to the next questions.

What happens when you are trying to start the engine?

Ignition ON
1. Can you turn the key in the ignition? Yes No 
2. When you turn the ignition ON:
Do the lights come on in the instrument panel? 
Yes No 
Does the "Security" or Key-shaped light stays on or flashes in the instrument panel? Yes No 
Does the "Check engine" light come on? Yes No 
3. What happens when you turn the ignition key to the "Start" position?
Nothing happens, the engine won't turn over.
There is a click (or repeated clicking) but the engine won't turn over.
The engine turns over (cranks) very slowly. 
The engine cranks progressively slower, then just clicks. 

If the starter cranks normally, but the car won't start continue to the 

What to check first

If the car won't start, check the basic things first: 
• Is the battery OK? Read the next paragraph how to check the battery. 
• If the car doesn't start with the automatic transmission in "Park," does it start in "Neutral"? Sometimes a car won't start in "Park" but starts in "Neutral" because of a problem with a neutral safety switch. Read more about neutral safety switch here: how a car starting system works.
• Are the battery cables tight and not corroded? 
• Do you think Is there enough fuel in the tank? It's a common situation when the fuel gauge isn't working properly and the car runs out of fuel with the fuel gauge still showing some fuel left. There is no way to check the fuel level other that the fuel gauge. But you can estimate how long did you drive since the last fill up. Read also about signs of low fuel level on the second page of this guide.
• Is the "Security" or key-shaped light in the instrument panel stays on or blinking? Read below about the security light.
• Does your car have an anti-theft system that for some reason doesn't allow the car to be started?

How to check the battery

A discharged or dead battery is one of the possible reasons for a car not to start. Sometimes we just forget to turn off the dome light or something else, or it could be some faulty component of the vehicle electrical system that drains the battery down. Sometimes, if the battery is old, it could just die one day, even if the day before it was OK. In either case, if the battery is low on charge, it won't have enough power to turn over the engine: you may hear some clicking noise or the starter may turn very slow when attempting to start the engine. 

Here is a simple way to check if the battery is discharged:
Turn the windshield wipers on. If they move very slow, much slower than usual, the battery is probably low on charge. Look at the dome light. Does If it gets very dim when you try to start or when you turn the wipers on, the battery is most likely discharged. 

If the battery is relatively new, it can be recharged. One way to do this is to jump start your car and let the engine run for a while to re-charge the battery. Read below about jump starting. One thing to be aware: if the battery is more than 4-5 years old, it might be completely dead, so it won't take charge and the car will not restart again after you shut it off. In this case, you may need a new battery. A problem with the vehicle's charging system can also cause the battery not to re-charge.

The key won't turn in the ignition

If the key won't turn in the ignition, it could be for a couple of reasons: Often this happens when the steering is locked by the ignition lock with the front wheels turned aside (e.g. when parking on a hill) or when one of the front wheels is pushed against something (e.g. curb stone). In this case, try turning the steering wheel left and right while gently jiggling the ignition key - this might help to release the steering lock.
Another possibility is that there is a problem with the ignition lock or the key itself. This happens; the key and the lock mechanism wear over time. Try to use a spare key. If nothing works, your local dealer is the best place to call.

No lights on the instrument panel

If you turn the ignition on and no lights come on at the instrument panel means that there is no power coming from the battery. It could be a dead battery or often a bad ignition switch could cause this. Turn the headlights on, if they work, means the battery has power, so the problem could be with the ignition switch or wiring between the ignition switch and battery.

If no lights coming on in the dash and no other electrical consumers work, the battery could be completely dead or there is no connection between the battery and the vehicle electrical system. Check if the battery terminals look tight. If the battery is completely dead, jump starting might help.

"Security" or Key-shaped light stays on or flashes on the dashboard

Security light flashing
Many cars are equipped with an immobilizer or a security system that allows the engine to start only if the correct key is used. You can find more information about the immobilizer in your owner's manual. 
Basically it means that an ignition key has a chip inside with the security code. When you insert it into the ignition, a sensor for the security system reads the code. Normally when you turn the ignition on, you would see a "Security" light to come on for a short time and then it would come off. That would mean that the code in the ignition key is correct and the car is allowed to start.

If when you turn the ignition ON, the "Security" light stays on or flashing means that your car security system does not recognize the key or there is some problem with some part of the security system itself.
Some GM cars, for example, had a problem with the security system sensor located at the ignition lock. Sometimes, the key is just need to be reprogrammed. You can find the information how to re-program the key in your owner's manual or just Google it. In some cases there is a simple procedure to re-learn the key that fixes this problem. You also can try the spare key and if nothing works, your dealer is the place to call. You dealer can check your immobilizer and reprogram the ignition keys if needed.

The "check engine" light does not come on

Check Engine Light
When you turn the ignition ON before starting the car, the "Check engine" light is supposed to come on indicating that the engine computer (also could be called ECM, PCM, or ECU) is powered on. If the "Check engine" light does not come with the ignition ON, it's possible that there is no power coming to the engine computer (e.g., due to a broken wire, faulty main relay, burnt fuse, etc.) or that there is a problem with the engine computer itself.

The starter won't crank

If nothing happens when you turn the ignition key to the "Start" position, it means that the starter motor doesn't turn over the engine. Most commonly this could be caused by a dead battery; here isHow to check the battery
If the battery checks out OK, but the starter still won't crank, there could be a number of possible reasons. Here are some of them:

 The ignition switch could be bad - it's a common problem. An ignition switch is an electrical switch installed at the back of the ignition lock mechanism. If jiggling the key in the ignition helps start the car, the ignition switch should be checked first.
 The starter solenoid control wire could have a bad connection.
 The starter motor itself or a starter solenoid could be bad.
 A neutral safety switch is bad. If a car doesn't start with the transmission in Park, but starts in Neutral, it could be caused by a problem with a neutral safety switch.
Read more about starting system
 A problem with vehicle's security system or some other electronic control module (e.g., ECM, BCM) may also prevent the starter from operating. 

I can hear a click, but the starter won't crank

It's a very common problem: you turn the key to the "Start" position, but the engine won't crank; all you hear is a single click or repeated clicking coming from the engine compartment. This has happened to me many times. Very often this could be caused by a weak battery or poor connection at the battery terminals. Sometimes a battery cable can get corroded inside causing the same problem. In some cases a bad connection between the negative battery cable and the engine (bad ground) can cause the same symptoms. 
Of course, there could be other reasons, but most often this happens when there is not enough electric current for the starter motor to turn over the engine. 
See this paragraph: how to check the battery
Also, check the battery terminals to make sure they are not corroded. Here is a photo how a corroded battery terminal looks: Car maintenance checklist: Battery
If the battery is OK and the battery terminals appear clean and not corroded, the starter solenoid, battery cables or the starter motor itself could be a problem. For example, a problem with the starter motor or solenoid is a fairly common cause for the 2000-2006 Ford Taurus not to start. Earlier models of this vehicle had some problems with starters too. A similar problem with the starter solenoid in 1998-2002 Toyota Corolla sometimes can also cause a condition when there is a click but the starter won't crank. Similarly, in 1998-2001 Toyota Camry a problem with the starter solenoid terminals could cause the condition where the starter would click, but would not crank. In either case the starter motor needs to be rebuilt. Read more here: Starter motor, starting system.

The engine cranks very slow and won't start

This also might be caused by weak or discharged battery; here is how to check the battery. If the battery is OK, the battery cables could have a bad connection at the terminals or the starter motor itself could have a problem. Sometimes, the starter motor armature bushings wear out and the starter armature rubs against the field coils inside the starter motor; this will also cause the starter motor to crank very slow. If this is the case, the starter motor will need to be rebuilt or replaced. Another reason, the engine could have an internal mechanical problem (e.g., lack of oil, very old engine oil, etc.). Check engine oil, just in case. Read here how to check engine oil.

The engine cranks progressively slower, then just clicks

If the engine cranks slower and slower until it just clicks, means the starter motor doesn't have enough power to turn over the engine. This problem should be fairly easy to diagnose, as there are just two cables (positive and negative) to deliver the electric current from the battery to the starter motor. Once again, a very weak battery is the most common problem in this case. A bad starter motor also can cause this issue. And of course, a poor connection or corrosion at the battery terminals or bad battery cables can also cause these symptoms. If the battery is very old, you might want to start with replacing the battery; a new battery is not very expensive.

Jump-starting a car

A jump start is a way of starting a car with a weak battery using a power from a good battery in another vehicle. You will need jumper cables and another car with a good battery, and it's a fairly quick procedure. Last time my battery died at a grocery store parking lot, a fellow driver helped me to jump start my car from his vehicle - luckily, I had the jumper cables. We connected the cables, my engine started right away, and in a couple of minutes I was on my way to the parts store to get a new battery.
Now, the process is simple, but you should check your owner's manual for the right way to do this in your vehicle, because different cars have different locations of the connection points. It's important to connect the jumper cables the right way, so check the instructions in your owner's manual carefully. If you don't have an owner's manual, many car manufacturers offer to download an electronic copy from their websites. Read here: Where to download an owner's manual 
Be careful, a person I know had to scrap his car after he accidentally mixed the positive and negative cables while jump-starting his car; this caused extensive damage to his vehicle's electrical system.

In this guide, we are going to look into no-start problems when the car engine cranks, but won't start. If your engine won't crank at all, check the first part No-start: Car won't crank.
First, we are going to look at what is needed for a car to start; this could give you some ideas. Next, we are going to look into the situations when something that happened earlier might have caused the car not to start. For example, if a car won't start after the rain, the problem could be cause by water getting into ignition components; read more below. 
Also, if you somehow can manage to start a car, looking into what helps to get it running can help you to find why it wouldn't start other times. Another trick to find a problem is checking for common problems with you car make and model; read more below.

What is needed for the engine to start

If the car engine cranks normally but won't start, at least you know that the battery and the starting system are working. If the battery was low on charge, the engine would crank very slow or wouldn't crank at all; if the starter was bad, the engine wouldn't crank. So let's look at what else is needed for an engine to start and what are the common problems: 

1. Compression in the engine cylinders. The normal compression in the engine cylinders is 120-170 psi. The engine won't start if the compression is lower than 70-80 psi. The compression could be low for many reasons, such as a leaking head gasket, broken timing belt, incorrect timing, broken pistons, burnt or bent valves, etc. Often, overheating the engine causes the pistons to break or the head gasket to leak. In either case there won't be enough compression in the engine cylinders to start. When the compression is low, it feels like the engine turns over unusually fast, like if the engine has no resistance. 

2. Proper timing. The engine camshaft(s) that opens and closes the engine valves is precisely timed to the crankshaft through a timing belt, chain or gears. If, for example, a timing belt is broken or a timing chain got loose and jumped a tooth, the engine will not start or will run poorly. Another common problem is a stretched timing belt or chain. Often, in a high-mileage car the timing chain stretches causing the ignition timing to be too retarded to start. A stretched timing chain, for example, is a common cause of long-crank or crank-no-start problems in some 4-cylinder Nissan engines (Sentra, Altima).
3. Fuel and spark. A car engine needs proper air-fuel mixture supplied to the cylinders and a strong spark on the spark plugs in the right moment to ignite the mixture, so both the fuel delivery system and the ignition system must be in working order. Common problems with a fuel delivery system include a bad fuel pump, bad fuel pump relay or wiring. Another very common issue is when the car runs out of fuel, but a faulty fuel gauge still shows some fuel in the tank. A bad ignition coil pack and a faulty distributor are the examples of ignition system problems. 
In addition, in a modern vehicle both the fuel-delivery and the ignition system are controlled by theengine computer. The engine computer in turn, is connected to the Transmission Control Module (TCM), Body Control Module (BCM) and a security system, so a problem with either of them can also cause the engine not to start. Here are few examples: a bad BCM (Body Control Module), defective crankshaft sensor, defective security system sensor all can cause a no-start problem.

Did anything happen earlier that could cause the problem?

Sometimes, what happened before can give you a hint why your car won't start. Let's look at some common situations: 
The engine was loosing power and died gradually, like if it run out of gas. It's a common problem when the fuel level sensor doesn't work properly and a vehicle runs out of gas while the fuel gauge still showing some fuel in the tank. A usual indication of low fuel level is lack of power that gets worse gradually. If there is a very little fuel in the tank, the engine may start and run for a short time, then die again. You may also notice that the engine chokes off when you press the gas. There is no way to check how much fuel left in the tank other than filling it up. One indication that there is no fuel in the tank could be the fuel pump that sounds differently. A fuel pumps typically runs for a few seconds when you turn the ignition on. In most cars, a fuel pump is installed in the fuel tank; it sounds like a quiet buzz coming from the back of the car. If there is no fuel, it may sound differently. 
The car was repaired recently
. If your vehicle's engine was repaired recently, take it back to the repair shop and ask them to re-check it. Maybe they just forgot to re-connect some wire properly after repairs. This happens. For example, if yesterday you had your timing belt replaced and today a car won't start, there is a good chance that something wasn't connected back properly.
The engine won't start after water got into the engine compartment. If your car died after water got in the engine compartment, for example, after washing the engine or after driving through a deep puddle, this could be caused by water shortening out some of the ignition components. Water could get inside the distributor cap or on the ignition coil and ignition cables and this could cause problems. Often this happens when a tune-up hasn't been done for a long time. Take or tow your car to a mechanic to check it out. Often, once the ignition components dry out, the car may start again. If your car won't start after water gets into the engine compartment, a tune-up is a good way to start.
A car won't start after being overheated. Overheating the engine can cause a lot of problems and if the engine doesn't start after being overheated it's not a very good sign. Have your car checked out for compression in the cylinders. A leak down test also can help.

If you can get the engine to start, what helps?

Sometimes a car may have an intermittent problem, when it starts fine most of the time, but once in a while it doesn't. Such problems that are not presented at all times could be very difficult to diagnose. What will help to find a problem of this type is if you notice when, under what conditions the car doesn't start and what helps to get it started. For example, if you notice that wiggling the ignition key helps to get the car started, it may tell your mechanic that the problem is likely with the ignition switch, which is very common. Or, if the security light flashes on the instrument panel each time the car doesn't start could tell your mechanic to begin with checking the security system.

Research common problems

If your car won't start, there is a good chance that someone else had a similar problem with the same car as yours and already found a solution. There are websites where you can search problems reported by other owners: 
Safercar.gov - click 'Vehicle Owners' then 'Search Complaints'. 
Carcomplaints.com - search for common complaints.
For example, if you search the NHTSA complaints at Safercar.gov for the 2002 Chevrolet Impala, selecting "Electrical System" you will find a number of no-start complaints related to the "Passlock" feature. Now, Google "Passlock" and you will find a number of treads at various forums describing the problem and ways to fix it. 
By the way, searching online forums dedicated to a make and model you have can also be helpful in finding a solution for your problem. 
You also can search Technical Service Bulletins (TSBs) for your car, if a similar problem already happened to other same-model cars, there is a good chance that the car manufacturer issued a TSB describing this problem.

Common no-start problems

A bad ignition coil could sometimes cause a problem where the engine cranks but won't start in some 1996-2000 Honda Civic models.
The 2002, 2003 and some newer Nissan Altima cranks but won't start. There is a couple of TSBs on this issue. One of the possible problems could be a bad camshaft position sensor (CMP Sensor). A bad crankshaft position sensor (CKP Sensor) is another possibility. 
The 1998-2002 Honda Accord won't start when hot, but start once cooled down. Sometimes a bad main relay (PGM-FI) can cause this problem. The main relay is located under the dash, near the steering column. A bad ignition switch can also cause a no start problem in this model Honda Accord. Some Acura models had the same issue too.
A bad crank sensor can sometimes cause a problem with some 90's-00's Jeep Cherokee when the vehicle would crank but won't start. 
Some 90's Volkswagen models (Golf, Jetta, Cabrio) won't start after water got into the engine compartment due to a bad ignition coil.

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