car engine does not start

there are so many causes why an engine does not start. Some are the basic as follows:

A SUDDEN STOP WHILE THE ENGINE IS RUNNING.
A.     THE TIMING BELT OR CHAIN MAY HAVE BEEN CUT.

 FIRST AND THE MOST IMPORTANT IS TO CHECK IF THE TIMING BELT IS NOT CUT  OR THAT BELT GOT SLIP THAT HAVE CHANGE THE TIMING OF YOUR ENGINE. If your engine type is an INTERFERENCE TYPE , THEN DO NOT START THE ENGINE BECAUSE THE VALVE AND PISTON MIGHT BE BROKEN OR DEFORMED. ASK A FRIEND TO CHECK FROM INTERNET IF YOUR CAR IS AN INTERFERENCE TYPE.

WHAT TO DO TO BE ABLE TO CHECK IF IN FACT THE TIME BELT IS CUT.

1.assuming engine not interference type.  remove the distributor cap.  Have someone crank the engine and you check if the rotor of the distributor is moving, if not moving then , your belt is cut or your camshaft is cut also.   then you have no way to make the e engine runs. if you are alone , remember the position of the rotor , then you crank the engine for 2 seconds , if the rotor did not move , then belt or camshaft is cut.

2. if it is an interference type , like HONDA VTEC ,  i suppose.  Remove the valve cover , remove the upper timing cover and you will see if the belt is cut.

 if the above is not so., then......

B..   gasoline in the tank got empty.
               a.  gas gauge in dashboard shows at lowest point.  except when it is defective.
               b. if practical ,  you open the drain plug of gas tank ,if  there is no gas coming out, that is the reason ,  if there is sufficient then it is not the reason for the stalling.

C..  fuel pump is not functioning.
              a. remove the hose leading to the fuel rail from the fuel filterr or remove the fuel filter hose attached to the fuel rail.
              b.get a container and dip that hose to the container, start the engine, if the coming out of the gas is strong , then , you may presume your fuel pump in your gas tank is operational, its relay is also OK.
              c. if the gas coming out is none then, maybe your pump is defective or the relay is defective.  in honda vtec, the relay is situated below your steering wheel.  switch on your key to on position , you must hear a click sound from the relay, indicative of it being good, if it does not then replace it.
               d. putting new relay and it clicks, repeat the letter b. if there a strong gas coming out then the old relay is the reason for the stalling. If there is still no gas strongly coming out of the fuel filter hose, then maybe the fuel pump is defective.
                e.  ask somebody to come near underneath the gas tank, you switch on the key to ON POSITION,  a sound must be heard coming from the fuel pump imbedded to the  gas tank.   if not , your fuel pump is not operating. Repeat this procedure once more because , you may have miss  hearing  the sound from the tank.
               f. . if a sound is heard from the gas tank, and  still no gas coming out from the hose the moment you start the engine, then ....
               g. the fuel filter is totally clogged, remove it and try to blow a strong air.
               h. if proven to have remove the dirt, and still no gas coming out, then trace your fuel line from the tank to the fuel filter for a crimp fuel line that prevented the gas to flow to the fuel filter.

if all things relative to gas delivery from tank is all fixed and yet no start still.  what another reason for the sudden stop. 

D.  THE IGNITION COIL had BECAME DEAD IMMEDIATELY.
       If the ignition coil  is located inside the coil.
         a. remove one spark plug cable from the distributor cap.
         b. put or insert a spark tester or spark plug into the port of the distributor cap.
         c. have someone start the engine , observe if there is spark coming from the tip of the spark plug, if there NO  spark ,  the following is the causes of no spark,  DEFECTIVE IGNITION COIL, DEFECTIVE  IGNITER , OR DEFECTIVE ECM .( electronic control module)
         d. to check ignition coil,  remove the distributor cap .
         e.  the ignition is the one with two wire in it.
         f.  get a test light ( a bulb with two wires, +  and - ) ( assuming you do not know which wire is positive), attached the positive terminal of that lest light to anyone of the two wire, and the other wire of testlight to a ground.
         g. switch on the ignition key,  if your connection is correct  , the bulb MAY LIT.
         h.  try repeat the procedure in f, but this time reverse the connection, that is , the wire you connect should be interchanged. if it bulb lighted , it means there is LIVE current reaching the COIL and the igniter.
 But this does mean that your ignition coil is already good  because maybe the IGNITER which should deliver a switching signal to the ignition coil is not working so that the coil would function. 
           i. get again , a test light , connect the positive terminal to the + battery, and the ground wire to the wire that came from the IGNITER to the ignition coil.  THE igniter supposed to have a 4 wire , one live wire, 2nd  goes to ignition coil, 3rd goes to tachometer, 4th goes to the ECM.
         j. start the engine, if the test light blinks , therefore it means that the igniter is delivering signal to the coil , but how come the coil is not delivering a spark to the spark plug in letter b., therefore the coil is defective.
         k. replace that coil or change it. 
         l. if the test light did not blinks in letter J., maybe the IGNITER is the one defective.
         m. the igniter is for sure is receiving a live current as mentioned in letter h., so what has to be check is the wire that goes to the ECM from the igniter. there are four wires in igniter, one live current, which you have already pinpointed, 2nd one goes to the ignition coil, already pinpointed, the remaining two goes to the socket terminal near the distributor.  one of which goes to the tachometer, and the other one goes to the ECM, this is the wire that you have to test, but offhand , you may not know which of the two wire goes to ecm. If you can searched thru internet , so much the better, but if not, you have no choice but to adopt TRIAL AND ERROR APPROACH.
      n. this time led light should be used.
      o.  put back the distributor cap without the spark plug cable.
      p. get an LED bulb, put a pointed needle on the negative terminal of the LED, pierce with a pointed needle with a wire on it any one of the two wire ( as a guess) and  the other terminal of LED to the positive terminal of battery.
   q. start the engine , if the LED blinks , then the ECM IS OK.  IT SEEMS THE IGNITER IS DEFECTIVE. 
  R. if the LED did not blink, maybe the distributor pick up coil is the one defective.


E..   THE BATTERY BECOMES DEAD EVEN IT IS NEW OR WHETHER IT IS OLD.
      While the engine is running , the ALTERNATOR is presumed to be producing an electric current to deliver it to the battery so that the battery could supply the necessary power to all the electric consuming thing in the whole car, including the power to the ECM, COIL, SPARK PLUG etc etc.

In the event that the alternator becomes defective , especially while the engine is running , momentarily the engine can still run untill the reserve power of the battery is consumed, that is the time that the engine will stop..
That means , even the battery is in the dying time,or dead, the engine will still continue to run ( though it could not crank the starter) because the alternator will be the one to deliver the necessary power to the ignition system.

    HOW TO CHECK  IF BATTERY BECOMES DEAD DUE TO ALTERNATOR FAILURE.

1.  Open the headlight,  if it is dim ,   then battery is dead, even it is still new. But if the battery is old , of course expect a dim light.   Better still, remove one battery terminal, get a wire, put one end of it to the positive pole of battery, the other end scratch it to the negative, the spark must be strong , if  not the battery is discharged .
2. Since the car stops while running , and the battery becomes dead due alternator failure , even if you try to push the car to start the engine , it wont because your battery is dead and no electricity can be supplied to your ignition system. 
3, if your battery is still new , it can be charge for the meantime to an ELECTRICAL SHOP, so that you can start the engine to reach that  ELECTRICAL SHOP or be back home ,. but only to the extent of the power of the battery because the alternator is dead.  But if your battery is old or actually dead , maybe it would not received any charge.
4. But before going to the charging shop , initially check the single wire at the rear of the alternator if that is cut or open, because this is the one that delivers current to the battery. Put it back.  Now you may try to PUSH START  the engine , ,who knows it may start..
5. Finally when you reach home and your battery is still charged, ( see no.3)  while the engine is still running, remove one battery terminal , if the engine stops , then your alternator is actually dead.

Please be aware that while the engine is running and if you remove the battery , the engine will still continue to run because the alternator will be the one to supply the necessary power to the ignition system, except when your alternator is dead..