What would cause a 2009 F150 4.6 gas engine to sometimes turnover but not start?? It turns as if there is no spark or fuel and then you try it a few minutes later and it starts like there was no probl

Troubleshooting Car That Won Start dummies or this link... Problem 5 Engine Cranks But won Start

Define turn over , the engine cranks over but doesn't start ? Turn the key to the start position and it does nothing ?

Are any warning lights lit on the instrument cluster , check engine , service vehicle soon , security etc... Look in the engine compartment , under the vehicle for fuel leakage , turn the key on then off to prime the fuel system an look for leaks on top of the engine , fuel pressure regulator ! If the engine does crank over an doesn't start , passably the spark plugs are fuel soaked - fouled !

check to see if the cam shaft is turning while cranking the engine (broken timing belt) run fault codes to find faulty sensors.

A car needs 3 things to start. Air, fuel, and spark. Check that it can get air by removing the air cleaner and inspecting it. Leave the air cleaner off for now. Try a squirt of starting fluid into the carburetor (not a lot mind you, just a quick squirt). Be prepared to quench a flame if the engine backfires through the carburetor (have a wet towel handy). Crank the engine. If it fires, you have spark. If it does not fire, you have ignition problems. If it fires and stalls out quickly, you have fuel problems.
For fuel problems: Be sure you have gas! (I know it is obvious, but check the tank!). If the car has not been used for awhile, the gas may have gummed up the carburetor. While it is possible for the weekend mechanic to take a carburetor apart and clean it, it is probably best left to a professional mechanic. Verify that you are getting gas to the carburetor by detaching the rubber gasoline hose at the carburetor. Most cars today have electric fuel pumps, so turning on the ignition should result in a stream of fuel from the gasoline hose. If not, crank the engine and see if a mechanical fuel pump moves the gas. If you get no gas, find out why or your car will never start. If you get gas, the carb is probably gummed up. It is best to conduct this last test into a mason jar to catch the gas, and it is best to postpone the cigarette break until after the test is complete.
If you suspect the ignition, pull a spark plug. It should look clean and whitish to light coffee color. If it is filled with carbon and oil, you have other engine problems. You can look for an ignition spark by laying the plug case against the engine while it is attached to the distributor wire. Crank the engine and you should see a spark jump the gap at the spark plug tip. This spark is often small and hard to see in sunlight. Do not perform the spark plug test in the temporal vicinity of the fuel test. A hot spark with gasoline nearby is dangerous.

A car that turns over means that at least the battery is good. Try next to insure it has air, gas, and spark.

The first thing is to check it for spark and fuel, try spraying starting fluid spray into the throtlebody and see if it runs for a few seconds, if it does then we know its getting spark and not fuel, this may be caused by a bad fuel pump, another trick is to have someone try to start it while you beat on the bottom of the gas tank with a rubber hammer , this will shake the pump and sometimes make a connection to start, if this works then pump is bad replace it, good luck, hope this is helpful.

Hi,here's what you need to do to find out the cause of your problem, and get your car back on the road.

• Make sure that you have enough gas in your car. This sounds like common sense but many people don't think to check this before wondering why their car won't start. Try to refill your tank when it is no less than one quarter full, or you risk getting stalled or stuck somewhere.
• Verify that the battery has a full charge. A battery with a low or partial charge can cause the engine to crank too slow preventing it from starting. Sometimes a jump will fix this problem, but if your battery is more than five years old you should consider replacing it, especially if winter is only a few months away.
• Check to see if your fuel pump is turning on. This can easily be done by putting your key in the ignition, turning it to the "on" position, and listening carefully with your ear pointed toward the back seat. If your fuel pump is working you will here an electric "whirring" noise for about 2 seconds every time you cycle the key on and off. If you hear nothing then your fuel pump is faulty or not getting any power.
• Find out if the engine is getting gas to it. Sometimes a plugged fuel filter or a problem with the fuel injectors can prevent the engine from getting any gasoline. To check this remove the air cleaner and smell inside the throttle body or air cleaner housing. If the engine is getting enough gas you should be able to sense a strong gasoline smell due to the amount of uncombusted fuel left inside the intake manifold.
• Determine whether the spark plugs are firing. If there is plenty of gas but no spark, the engine will crank but not start. Unplug one of the spark plug wires and plug in a spark tester. Have a friend get in the car and crank the engine while you watch to see if the spark tester illuminates. You can usually purchase a spark tester at an auto parts store for about ten dollars.

if you dont have test equipment then you can determine what is likely wrong by the followint:
spray a little starting fluid or gas in the air intake (without the air filter) ... if it starts and runs for a few seconds then the ignition system and timing belt are likely ok .. you should then check the fuel pump and fuel filter ( a mechanic would test for fuel flow and pressure) .. you could have a blown fuel pump fuse ..if your car starts after spraying the starting fluid and continues to run but very rough .. then you might have water in the gas (more common as weather changes cause condensation). ... if the car doesnt start even with the starting fluid then you likely have an ignition problem .. you can remove an ignitiion wire and test for spark as the engine turns over ... if there is no spark then you could have a bad ignition module, coil or other ignition component.. if your lasabre has lots of miles on it you might check to see if it has a timing belt vs a timig chain .. the bels have a limited life time and can break or skip a tooth ... if it startted and ran a few seconds with the starting fluid then the belt is not the cause.. .

if its carberated, u need to clean that out. if its fuel injected, replace the fuel filter. if it stil dont work. then u have a fuel injector problem

when the problem is happening, you need to check to see if you've lost spark or fuel. when you try to restart the car,can you smell gas? if you can,you need to pull off a spark plug wire and put a screwdriver into the end of the wire. set it down 1/4" or so from a metal ground. have someone crank the engine, see if there is a nice strong spark. if so, you're fuel pump is probably faulty. it's inside the gas tank

Check For fuel on the fuel rail with the engine stop. If there is fuel, then check for spark at one of the plugs or Kal pac area.

If all is well you have crank sensor problem.
Good luck