What to do if your car doesn't start (3-1)

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.

  • An empty tank does not run a car. However, the only way we think we can find out whether there is fuel in the tank is to depend on the fuel gauge. What if the fuel gauge has malfunctioned and is stuck at half-full? A quick solution is to open the filler cap and place your ear close to it. Ask someone to shake the car from side to side. The resultant sloshing sound inside gives a fairly good idea of whether there is sufficient fuel there. Applies to both, diesels and petrols. If you've been caught unawares with an empty tank, well, it's time to deploy / borrow a jerrycan.

  • Once you have filled up, turn on the ignition and wait for a minute or two to allow the electric fuel pump to prime the fuel injection system / carburettor, before trying to crank the engine.

  • If you do have fuel in the tank already, disconnect the fuel feed pipe in the engine and hold its tip inside the mouth of the jerrycan. Then, ask someone to turn on the ignition. This will cause the electric fuel pump to run and you should be able to see a steady stream of petrol filling the can up (at least 1 liter per minute).

  • If you have no fuel coming out, the fuel pump inside the tank isn't working. It could be a blown fuse or relay (simple to replace a fuse, or tap the relay a few times and see if it comes back to life). On the other hand, if the fuel pump has failed, you need to tow the car to a service station and get a replacement.

  • If fuel flow is erratic (intermittent or very slow flow), one of the fuel filters (either the coarse filter inside the tank or the fine filter inside the engine bay) is choked. Try shaking the rear end of the car from side to side to dislodge some of the muck from the in-tank filter, then take out the engine-side filter and tap out the dirt in it (fill with petrol, shake well, then tap gently on a hard surface with the "IN" side facing down).

  • Also check the fuse / relay for the FI pump (for modern fuel-injected engines).

  • For a carburetted engine, make sure that the engine isn't flooded with petrol, and that the choke isn't applied.