A driver's worst nightmare is that time when his car won't start. Or, the engine dies exactly when he is negotiating a tricky crossing. It's even more worrisome if the driver is a lady (especially in India) and the sun has already set, or if the location is a lonely highway instead of the city. This is the time when one regrets not knowing a little more about how cars work.
Good news is, diagnosing why your car won't start isn't exactly rocket science. This guide, a little bit of common sense and a cool head might just be enough to get you back home.
Step 1: Understanding the Basics
Before you begin the process of troubleshooting, it is absolutely essential that you ensure your own as well as others' safety by pushing the dead car safely to the side of the road.
There are essentially 3 systems that start your engine up:
In the next few posts, we shall progressively try to identify what is preventing your engine from running, and explain some quick repair methods. The ultimate solution for the mechanically-challenged individual is to call the manufacturer's helpline and / or have the car towed to a workshop. But before you do that (it can take an hour or more for roadside assistance to turn up), let's try to get you home safe.
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Step 2: Checking the Electrical System
About Push Starts:
A push start may or may not work with the problems listed below. Do note that a push start won't get you anywhere if your battery is completely flat and the fuel delivery system gets no power. As an example, check this thread out. Also, not all cars can be push started; check your owner's manual for details.
The commonest culprit at the root of preventing your engine from starting up, or that caused it to die suddenly, is the electrical system. Turn on the ignition switch, but don't crank the starter. Are all the telltale lights on the dashboard coming on & fully illuminated?
If YES (all dashboard lights are on):
Determine if the battery has enough charge to be able to start the car. A quick way to check is to turn on the headlights and blow the horn. If the lights dim and the horn sounds hoarse, you have a nearly flat battery. It's push-starting or jump start cables to the rescue!
If there are absolutely NO telltale lights on the dashboard:
Be prepared that the fuse might blow again, in which case there is a short circuit somewhere and you need to summon professional help.
If the starter motor is turning over, but is slower than normal:
If there is no noise from the starter at all:
If you hear an audible "click", but the motor doesn't turn over:
If the starter motor churns over normally, but the engine will not fire:
The engine starts, but refuses to rev up or dies out after a few seconds:
WARNING: Do not continue to run down the battery by repeatedly cranking the starter motor, if the engine turns over well but will not start. You don't want a dead battery over and above other issues.Next Page >
Step 3. Part A: The PETROL Fuel System
Once you've made sure there are no gremlins in your electrical system, it's time to check whether the engine is receiving fuel.
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Step 3. Part B: The DIESEL Fuel System
It's more trouble to end up with an empty tank in a diesel car compared to a petrol car, because a diesel fuel system absolutely abhors air in the lines. Running on empty automatically means air has been sucked into the fuel lines, and one needs to bleed off air and prime the system.
Each type and model of diesel engine will be slightly different in how the bleeding is done. Almost all diesels (DI, IDI, CRDi) have a manual bleeding mechanism of some sort at the fuel filter. It's usually a lever (like some Jeeps), bulb (like the Safari) or a push-button (like the Scorpio) that is pumped repeatedly to push out air from the system.
If you are sure about there being enough fuel in the tank, you need to check whether a fuse for the in-tank (low pressure) pump has blown, whether the low pressure pump has gone kaput or if the filter inside the tank is clogged. The procedure is similar to what has been described for petrol engines in the post above.
Diesels also have this nasty habit of refusing to run when there's any water in the fuel. Unfortunately, petrol pumps have a nasty habit of selling you water-laden diesel in the monsoons (not completely their fault, but we need to blame someone, don't we?). Once that happens, the sedimenter bowl below the diesel filter fills up with water, a warning light shows up on the dashboard and the engine refuses to start / runs erratically / cuts out suddenly.
Here's how to drain water from the fuel filter of an Innova. The basics remain the same, but each car has its own required technique.
In rare instances, even with a tankful of diesel, the fuel system will draw in air and cut off the engine as a result. This can happen because of a leaking (damaged) fuel line, or (for avid off-roaders) if your car has tilted so sharply that the suction end of the electric fuel pump is not completely immersed in the diesel inside your tank. After the root cause is addressed (sealing a fuel line leak or getting the car back straight and leveled), the method of bleeding and priming the system remains the same as described above.
The adventurers among us have, on many occasions, found their diesel engines refusing to start at high altitudes in cold climates. Read these threads:
In most cases, if you've been caught unawares and cannot start your car at 14,000 ft and (-)5 degrees C, it's best to wait it out until the sun comes up and the weather is warmer.Next Page >
Step 4: Knowing when to say "I Give Up!"
Apart from the electricals and fuel feed system, there are a thousand other things that could go wrong and prevent your engine from firing up. If the culprit is the engine itself, there isn't much that one can do on the roadside, and towing the car to a garage is the only way out. From a blown head gasket to a broken crankshaft, from fouled injectors to ECM failures, from seized pistons to snapped timing belts, anything can make an engine dead and leave you stranded. Of course, it's another matter that the engines of today are far more reliable and robust than those manufactured even 20 years ago, but catastrophic failures are still not unheard of. Some of the reasons may be poor compliance with maintenance schedules and / or use of sub-standard spare parts. Here's a word of warning:
If you hear strange / unusual noises coming from your engine when trying to restart it, or if your engine stopped running after making weird noises, do NOT attempt to restart. The same applies if you find smoke pouring out of the engine bay or tailpipe, or if the engine overheated and stopped.
Some other notable vehicle-specific threads about failure to start:
Jump Start Cables:
Having a pair of jump start cables around might help you, a neighbour or a friend. The cost is marginal and it's a good idea to park a set in your car or garage (Image Source : Ebay.com). A basic tool kit & spare fuses are other essentials, while a jerrycan and tow straps can come handy.
Image Credits : The pictures of this Article have been sourced from various Team-BHP threads. Thanks to BHPians for shooting & sharing them.