WARNING

The suggestions given on this webpage are for emergency use only. In certain circumstances, using improvised parts to make car repairs can invalidate your car warranty. Do so only as a strictly temporary measure, and when driving conditions in your judgement make such repairs safe.

No petrol — blocked tank breather. Despite what your fuel gauge reads you could simply have run out of petrol.

Alternatively, you may have a blocked tank breather causing a vacuum in the fuel tank which is holding back the fuel.

Check for fuel by removing the filler cap and rocking the car. If you suspect that the remaining petrol is below the feed pipe try jacking up the rear of the car or bouncing it up and down. If even a cupful of fuel reaches the carburettor/fuel injectors it will mean that you can travel another kilometre or so.

If when you removed the filler cap you heard or felt an inrush of air, you have a blockedbreather. If the breather is in the cap or otherwise easily accessible, clear it with piece of soft wire. If you are unable to do this, just stop every few kilometres and remove the cap until you can have it repaired.

Check a mechanical fuel pump by first removing the fuel line from the carburettor side of the pump. Then reconnect the battery and turn the engine over. If petrol spurts from the pump — it is working. If not, check that the pump is securely mounted on the engine. Then, if possible, remove the fuel bowl (if fitted) and check that the filter is clear. If it is, remove the top part of the pump and check that the diaphragm is intact. If it is split you can try making a replacement from a piece of thick polythene, or rubber. If the diaphragm is intact check that the valves are not clogged with silt.

A pump which has no obvious fault may simply be worn. If you suspect this, remove the pump from the engine, operate the lever a few times by hand and then replace the pump using a thinner gasket — or if it only has a thin one, without the gasket. This will effectively make the pump work harder and may improve its efficiency.

Check an electric fuel pump by first removing the fuel pipe on the carburettor/fuel injector side of the pump. Then reconnect the battery and switch on the ignition. If the pump is working it will make a ticking sound and petrol should flow out. If the pump is not working, try giving it a sharp tap with a screwdriver handle. If this fails, check its electrical connections — particularly the earth which is usually through the pump's mounting bolts. If no power is reaching the pump, wire it to the battery. Some pumps can be partially dismantled to give access to contact breaker points. Check that these are clean.

If it is in the tank, as most are now, try to hear it run before you attempt to turn the engine over. You will have to get a tow truck if this is the fault.

Dirt in the carburettor usually accumulates in the float chamber so remove this first. Clean out any sediment with a clean cloth, check that the fuel needle operates and that the float moves freely and is not punctured. A punctured float can be repaired with epoxy resin filler or adhesive. If the float chamber is clean, the rest of the carburettor will probably be so too — but on a fixed-jet carburettor check that all the main jets are clear and on variable-jet carburettors check that the piston rises and falls smoothly and that the dashpot has oil in it. A piston may stick due to dirt or an off centre main jet. You can centralize the main jet by loosening the locking nut, tapping the jet until the piston drops smoothly and then retightening the nut. An empty dashpot can be filled with engine oil from the dipstick.