Everyone I know says you need three things to run an engine -
air, fuel, and spark. That is why they are not mechanics. There is a fourth, critical item needed to go with those three to make the internal combustion engine work - and that is compression.
The first, and quickest check the help isolate cause of a no-start condition, is a can of starter fluid. Get one and remove the cover to the throttle body (never spray starting fluid through the intake hose as it can damage MAF sensors!). Have a friend crank the engine and spray some fluid into the throttle body. If the engine fires up, stop and let it stall out. You now know that you have compression and spark. Your problem is lack of fuel, and that most likely is the fuel pump. If it doesn't fire, you can rule fuel out as the problem as fuel itself won't solve the issue. You must first check for compression. The first thing I always check for regarding compression on a no-start condition is the timing belt, if the car has a belt rather than a chain (you have a belt). This is because most owners don't read their manuals, don't check the maintenance requirements, and thus don't service their car as recommended by the manufacturer. Additionally, timing belt replacement is rather costly and easy to procrastinate away for as long as possible.
There are two ways to determine a timing belt issue. The first is the cranking speed of the engine. If the engine seems to crank over much faster than it usually does, then there is a good chance the belt has broken, since the extra load of the cam is not being felt by the starter. If that is not obvious, try to see the cam gears or shaft while cranking the engine. Some cars have a pop-off inspection hole over the cam covers for this. On some cars, you can see the camshaft if you look into the oil filler cap hole. If the camshaft is not turning when the starter is cranking, the timing belt is toast. Even if the shafts turn, the belt may still be suspect. They can shear teeth and jump time. So the next check would be a compression test of the cylinders. An out-of-time engine will have piston and valves out of sync, resulting in poor or no compression. Add to the fact that your engine is known as an interference engine, and if the belt breaks or strips, you will sustain internal engine damage that must be repaired before you can run the vehicle again (another reason for scheduled maintenance!). If all this checks out, then the next item to check for would be fuel (unless you rules that out earlier). In a quiet location, sit with the car door open and place the key in the ignition, and turn it to the RUN, not START position, and listen for a buzzing or humming noise coming from under the rear of the vehicle. It should last from 3-10 seconds. If so, you have a fuel pump that works. This sound is the priming, or pressurization, of the fuel system prior to starting. There still could be fuel issues, but the pump is by far the biggest suspect. The last item is spark. This is the hardest one to troubleshoot, since you can't see electricity. There are crank and cam sensors, as well as the ECM itself involved in the spark issue. You may decide at this point it is cheaper to have a mechanic look for this problem since parts swapping to easter-egg a spark issue can start getting costly.
The answer above is GREAT. Covers about everything.
I had this happen on a 2000 Focus and it was a timing belt (I hate them) that jumped a few teeth.
I finally got it running enough to get to Ford for the repair,since it was that complicated one and I didn't want to mess with it.
I have heard that you can unplug the MAF sensor in the air duct and they may run. I never tried that. don-ohio (:^)
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