Your car engine doesn’t start?


Learn how to diagnose the possible cause:

In today’s article we will address an inconvenient fact that happens to virtually all car owners not only from Brazil more also worldwide, so Attention! Whether your car is new or used if it hasn’t happened to you yet, be absolutely sure it’s still going to happen to you, too, not least because cars are machines, right?  And every machine is successionto failure.

Let’s face it, these things usually happen when we need the car the most! This reminds me of the times When I heard people telling that they had to start in the car to take a pregnant woman on the job to the hospital and the same did not work, or that story of the couple who went to the motel and had an unforgettable night there, more time to leave the car refused to work still in the motel garage , or even that most common story of the worker who went to try to start the car early in the morning to go to work and the car ended up leaving it in hand.

It’s really a complicated situation, not to mention it’s annoying. And in some cases knowing a little bit about the operation of the engine a car can help a lot, especially if there is no help nearby, or if the phone is not working either.

So no more talking. Let’s get to the point!

Where to start:

I will first try to show as clearly as possible what major mechanical and electrical failures can happen, and possible solutions to failures.

Starting System, Battery and Timing Belt:

Important notice: Before starting the car like crazy until you discharge the battery, give a ” tranquinho “, and push it down the street slope of your house…  Check that the Toothed Belt is not broken ! The procedure in some engines can be quite simple, just open a plastic cap to check. If you notice that there are pieces of strap inside her protective cover, or if it is loose, STOP! Don’t start any more games and don’t even think about stripping, ask a mechanic for help. Because insisting on starting or stridling the car can cause enormous damage with the right to blow the engine from the inside.

Busted Timing Belt.
Blown toothed belt.

When the engine of the vehicle does not start, it is necessary to evaluate some basic factors to proceed with the diagnosis of the problem, the first two points to evaluate is whether the vehicle has enough fuel in the tank, and whether the battery can “rotate” the car engine easily.


If the panel lights do not turn on or turn on weak ly, the battery may probably have died. And only your replacement can allow the car to work again. In some cases just make a ” pacifier ” with another battery charged, or give a ” push ” in the car can make the same come into operation, thus allowing you to reach a mechanic.

spy lights

If the lights light up in a strong shade, more when turning the key completely the engine does not make any sound, not even a snap, or does not turn, then you probably have only one electrical problem related to the starting engine of your car. In this case maybe a little ” push ” can make the car work until you reach a workshop.


Keep an eye out for the sound of the car’s starter when turning the key into the contact. If the sound of the starter engine sounds normally, turning the engine quickly, and the panel lights are in a strong hue then your electrical system responsible for starting is functioning normally, and now you can move on to the next step.

Lubricating oil level and coolant or radiator water level:

Check that the engine has lubricating oil in the crankcase through the level rod, and if it also has refrigerant or water in the radiator tank (if the water has gone off try to complete it, more if you notice that when starting the water is expelled again before the engine even picks up or after completing the water the car engine has braked and does not want to start then STOP! , Your car is having problems in the head joint, and it will be necessary to take it to the mechanic for proper repairs to be made).

oil level

Also remove the lid of the engine oil inlet and check for traces of any pasty substance other than oil in black on the inside, if there is any trace of a light or whitish brown substance may be that your car has previously overheated and had the head joint burned which causes the mixture of oil and water and compromises the operation of the engine , then stop the diagnosis here (it is important not to start or try to make the car work with the gasket of the burned head, to avoid further damage), contact your reliable mechanic as the engine will have to be opened for internal repairs.   If everything is “okay” go to the next step.


Timing and Belts:

Open the hood of the car, and check the condition of the belts, if they are all integral, and if there are no traces of rubber dust residue or pieces of them nearby.

In most cases of engine breakdown of a car, the timing belt or distribution belt is the big villain. In the case of the timing belt when the damage breaks, the damage can be great because the motor loses the timing between the upper and lower parts (valve control, and crankshaft), which causes internal friction between the valves and pistons.  In some cases the clash between the pieces is so violent that it ends up bursting the whole set, and the joke can come out very expensive.

In the case of toothed belt breakonly, a mechanic with basic knowledge will be able to perform proper repairs, as he will have to disassemble the engine to assess the damage.  With the timing belt broken or out of the correct timing the motor will not work no matter what you do.


In the case of the breakage of the auxiliary belt, or external belt the damage is less and you will only need to bear with the purchase of the new belt, perhaps some bearing of it, and the workmanship of the mechanic. With the auxiliary belt broken, the car may even start for a few minutes, the sooner it will stop again because the alternator will not be working and the battery will not charge, and the ignition system will consume all the remaining battery charge until the engine dies.  In addition to other problems…  the engine may overheat because the water pump will not be working, the steering may become very heavy without the assistance of the hydraulic steering system, and even the air conditioner will not work. Some freaks can even get to a garage with the car without the auxiliary belt.   If the distance is short it is worth even try, more is long give up!  It’s not going to work.

Ignition system, candles, candle cables, distributor, and coils

Otto Cycle:

If the car has a good battery, the engine is spinning fast when triggering the key contact, is fueled enough, and the belts are in good condition and well stretched, so the next step is to check that the ignition system is operating normally.


If you use pacemaker, have heart problems or have devices sensitive to electrical discharges, and electromagnetic fields with you;  THEN STOP HERE.  Never get your hands on automotive ignition systems because they produce very high voltages capable of carrying a pacemaker carrier, to death! The electrical discharges that reach the car’s candles range from 20,000 volts, up to 50,000 volts. 

To do a basic test on the car’s ignition system simply undock a cable from any of the candles, and secure it with a bonded high voltage, toward a point in the car bodywork or any point of the engine block and ask someone to start.  Simply watch if when starting start from the cable hole you are holding small electric sparks, sparks, or small voltaic arches toward the car bodywork, or the block.  Usually the spark is strong enough that popping snares are heard every time they come out of the candle cord.


If you take this test on all the candle cables and none of them come out electric sparks, maybe there’s the problem!  If your car has a distributor, remove the cable from the center of it and do the same test by directing it to a point in the car bodywork, and ask someone to start.  If you only see sparks coming out of this cable, it is very likely that the problem is in the distributor cover, or in the rotor internal to it.  All it takes is the exchange of the two, so that the car will return to normal operation.


If your car has no distributor, or you have not seen sparks in the test of any of the candle cables, then you will need to check the coil and its connections.  If the coil is with apparent cracks, leaking some oily substance from inside it, if it has signs of corrosion in its connection, or if you notice any broken or poorly seated wire, it may be that the defect is there. In some cases only the exchange of the coil by a new one can cause the engine to run again.  In other more complicated cases the defect may be in the wires coming out of the key contact inside the car, some bad contact may have undone the power connection of the system.


It is also important to check the fuse box, as the ignition system is usually protected by some fuse, if your car has manual is worth taking a read, so that you find the right fuse to be checked.  If you do not have a manual, you can check the fuses one by one, plus remember to remove only one at a time and check that it is not broken from the inside.  And whenever you remove a fuse from a place, make sure you put it in the same place it was.  They are colored just so they don’t get connected in the wrong places. Each fuse has its correct place never forget it, and only replace a fuse with one of the same color or numbering!

Warning: Replace a fuse of a color or number with another that is different – It may cause fires! Care!


Fuel pump, carburetor, electronic injection:

A simple tip that goes for cars with electronic injection, is to be aware of the sound of the electric pump that is inside the tank, in some models it is possible to hear a buzz when turning on the car key, before even starting, if before the car give the defect you could hear the buzz, and now that it does not catch you can not hear it , then check the car fuses, or ask your mechanic to check the pump, probably it may have burned.

In some cases the cause of an engine not going into operation may be related to lack of fuel supply due to some system failure, which pumps and makes the fuel dosage to the engine.  In older cars the system is mechanically managed by a device called carburetor, which is a very sensitive system to bad fuel, and dirt in fuel, and which requires periodic maintenance with great frequency.  By removing the cap, or hose from the air filter it is possible to visualize the inlet of the carburetor through which oxygen and gasoline are mixed, there is a kind of valve that limits the passage of oxygen/fuel and thus controls the acceleration of the engine.  This valve is called the Butterfly.

In cars with electronic injection the butterfly also exists! the difference is that the fuel injection is managed by a computer, and dosed through one or more injector nozzles.  Periodic maintenance is done at longer intervals, and this system is more reliable and sturdy.


A basic test to be done to diagnose the operation of the two systems, is to try to inject small amounts of lubricating spray, or a little bit of fuel on the throttle butterfly, while someone starts in the car.  If injecting the spray or fuel into the butterfly, the car engine threatens to pick up, or pick up and die soon after you can be sure that the defect may be there.

Warning: Throwing fuel or spray on the car engine butterfly can cause fires, explosions and burns!  If you don’t want to get a horrible sequel or have your car burned, then stop here!

In some cases, the engine may be drowned by excess fuel, a way to unburden a car’s engine, is to step deep on the accelerator to the limit, and start for 10 seconds, with pauses of another 10 seconds each.

Possible problems in the power supply system:

  • Fuel filter clogged, or too dirty – restricted.
  • Defective or weak fuel pump, (in cars with electronic injection it is electric and gets inside the fuel tank).   In cars with carburetors it is mechanical and is coupled to the engine block.
  • Carburetor locked, oxidized, corroded, clogged.
  • If the car has an alarm or cuts anti-theft current, it needs to be checked as well, as it may be with some defect or poor contact preventing the engine from running.
  • Once again check the fuses, and if you find any burned replace with one of the same color, or even number.

Problems with fuel recognition of the wrong flex system, or AF ratio:

In flex cars is the most common if it happens, it is the failure in the recognition of fuel after fueling a different fuel than it had in the tank of the car.

For example: A woman lives next to a gas station (about 1 km), and she usually always supplies her flex car with 100% alcohol every day, another beautiful day she decides to fuel the car with 100% gasoline when she was already at the gas station that exists next to her house, so so she does! And soon after went straight home, rested and walked only 1km which is the distance from his home at the gas station, distance that was not enough to burn the remaining old fuel (alcohol) in the pipe of the car system.  So the electronic injection interpreted that last time she supplied it, as if it had been alcohol, and stopped the adaptation strategy.

The next day when the woman tried to start her car, he didn’t pick it up like he did every day when she supplied it with alcohol alone, but why?

Simple!  Because the car’s computer didn’t recognize the fuel she supplied the night before, so the computer ” believes ” that all the fuel in the tank is alcohol, but it’s actually gasoline.  And as the injection ratio of the two fuels is very different the engine just doesn’t pick up because of a wrong mixture of air/fuel.

In some cars, just do the procedure to unburden for him to take:

Press the accelerator pedal until the end of your course, then start! And listen to the engine pick up again.   In other cases, it is necessary to force an adaptation using a specific automotive scanner.

It is worth remembering that the loss of data about the fuel contained in the tank also if the battery discharges, or if it is removed.   By default, each time the battery is removed, the fuel in the computer’s memory is reset to gasoline. Always!

Rotation, Pms, Inductive and Hall Effect Sensors

All cars with electronic ignition, and electronic injection have a sensor that serves to calculate the correct time at which the ” spark ” of the candles must happen, and the injection of fuel, so that the engine can function. This sensor can be located inside the dispenser, near the motor pulley, or somewhere in the block. This will depend on the make and model of your car.


In the event of failure of this sensor the motor will not start running, or will work intermittently, ie sometimes will pick up, others will not pick up.

It is difficult to diagnose a defect in a rotation sensor at home, because to take the test would require the use of an oscilloscope, which is generally expensive and needs technical knowledge to be operated. In other words, perhaps this problem only a mechanic can diagnose clearly and solve once and for all.

Another simple test to be done, is to remove a cable of candles and observe if when starting come sparks come out through the cable.  if the sparks are indeed absent at the time of departure, and you have already changed the coil, distributor cover, and rotor, the problem may probably be in this sensor.

It is logical that some defects can be seen in the naked eye, if you notice that there are wires cut, broken, or melted by the heat of the engine, probably the problem is this.

But remember that to spend as little money as possible to solve this problem, the best alternative is to ask a good mechanic for help.

Coded key, and immobilizers

In cars with electronic injection there is a system that protects the vehicle from possible theft, which is basically a chip with a unique code engraved inside the key, and this code is transferred and verified by the car computer every time it is started, if for some reason the code is not received or is incorrect or corrupted , the car will also not start running!

Coded keys are sensitive to falls on the ground, strong electromagnetic fields, and electro static energy discharges. There are even automakers that do not recommend leaving the key on home appliances such as tv, refrigerator among others.

See more in this article we have about coded keys here.

Electrical breakdowns, faulty control modules, flood problems…


Last but not least we have the control modules, which are present in cars with carburetor and cars with electronic injection, they serve to manage the ignition advance system, and the operation of the engine.  In case of failure in any of these components the car engine will also come into operation, and perhaps these problems are the most complicated to solve because there is a great technical knowledge of the mechanic, and if it is not good, probably will not be able to make your car pick up.

In cases of the car not picking up after going through a major flood, it may be necessary to disassemble its electrical and electronic part so that cleaning and repairs are done throughout the system, otherwise the vehicle will no longer work.

We hope you enjoyed today’s article! If you have any questions, if you need help with your car, or if you want to leave your suggestion use the comments form below!

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