Why 07 navigator cranks won't start? - 2007 Lincoln Navigator L

re check your work [that all sensors -- wiring and timing are correct]] scan for codes-- what did mech find--are you getting spark

If it is turning over (at a normal rate) but not starting you have either a fuel or an ignition prob. If it is turning over slowly, you have a battery low fault or a bad earth to your engine from the chassis.

most likely you have a bad crank sensor or fuel problem you need to check fuel pressure ,if you have enough pressure ,most likely you need crank position sensor,if you don`t have fuel pressure ,it might be your fuel pump relay or the pump, i would start with the relay first very unexpensive. you can also hear the pump if it`s working by cranking the engine and listening rear of the car for a humming sound .
good luck

you either have no spark , check spark plugs, or fuel pump isnt working , dont know the year of your lincoln but it could possibly be a fuse for your fuel pump ..

Does it only do that when the weather is cold?

If it does, it could be the fuel pressure check valve has a leak. One way to check it is to turn the key to the run position for 5-7 seconds before you start the engine. If it starts, that should be the problem.

If it still doesn't. You might have to reset the fuel pump. You can do this by removing the fuse from the fusebox in the engine compartment (it's a 15 amp fuse. I think it's # 17) With the fuse removed, crank the engine twice but make sure you don't hold it too long as you don't want to drain the battery. Two 3 second cranks should be good.

Put the fuse back in and start the engine. Should start then. Hopefully that solves your problem. I'm having the same issue and that is how I start my truck whenever is doesn't want to start. Seems like it only happens when I haven't started it in a while but seems fine when I start it within 4-5 hour intervals.

It can be faulty fuel pump or clogged fuel filter or its issue with starter or battery or may be problem with sensors.There are few possibilities that can cause these problem,there are few help links provided related to these issue. Click the link below and refer the troubleshooting procedure to solve the problem:-----
Engine cranks but will not start? http://technoanswers.blogspot.in/2012/02/engine-cranks-but-will-not-start.html
-------- Landcruiser prado won't start http://technoanswers.blogspot.com/2012/10/landcruiser-prado-wont-start.html ------- 2007 ford expedition engine cranks but wont start http://technoanswers.blogspot.com/2012/10/2007-ford-expedition-engine-cranks-but.html

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: Engine Cranking Fast but not Firing up? http://whatisbyme.blogspot.in/2012/05/1999-lexus-gs300-engine-cranking-fast.html

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1997 Oldsmobile Cutlass Ciera: The Engine cranks but not start? http://schematicsdiagram.blogspot.in/2012/04/1997-oldsmobile-cutlass-ciera-engine.html

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Mazda MPV cranks but will not start? http://technoanswers.blogspot.com/2012/01/mazda-mpv-cranks-but-will-not-start.html
-------- MAZDA MPV WILL CRANK BUT NOT TURN OVER TO START? http://technoanswers.blogspot.com/2012/01/mazda-mpv-will-crank-but-not-turn-over.html
--------- Vehicle Cranks Fast but Won't Start http://whoisbyme.blogspot.in/2012/07/vehicle-cranks-fast-but-wont-start.html

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How to test Crankshaft Position Sensor? http://fordrepairhelp.blogspot.in/2012/03/how-to-test-ford-focus-crankshaft.html

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These details will help,keep updated for more help.

If you mean the starter grinds from time to time and won't crank the engine when it happens, the problem could be a bad spot on the flywheel and/or a faulty starter. The starter uses a magnet and bendix gear to push the starter gear into the flywheel. If the magnet or bendix is weak, the gear will not engage and can damage the teeth on the flywheel.
You need to have the starter removed and check the flywheel teeth for damage.

You have to be specific about the engine turning over

That is done by the starter circuit

Some people call that cranking

Some people also say it won't crank, when they mean
it does crank, but won't start

Not turn over the engine -----

Old & Weak Battery
Dirty Battery Cables
Worn out Starter Solenoid -- you can buy & replace
without getting the entire starter
A bad Starter

Get hold of a scanner and find the code that comes out of your truck. Then start there.

This is a pretty common and expensive problem on GM vehicles. Read about on this link. Offers some solutions too so you can fix this yourself. http://vatspasslockpasskeysecurityhelp.yolasite.com/