I have a 2003 Lincoln Ls V8 that cranks but won't start. We have replaced the fuel pump and filter, ignition coils and throttle body. It is not reading any codes.
Spark. Is it getting fire? Compression. Have you checked the compression to make sure all cylinders are getting compression. Fuel. Is it getting fuel? What is the fuel pressure? Exhaust. Is the exhaust free flowing or could it be plugged?
Is voltage more than 12V on battery? Is there any smoke? Engine compartment or exhaust? Does engine crank faster than normal, normal or slower than normal?
Those are all questions to start with. All that said, take a serious look at the crank position sensor.
I would try replacing the Crankshaft Position Sensor - $25 - $30 on RockAuto. Mine went bad on my 2000 LS with V6. Wouldn't start - replace the CPS and it was fixed! (Tried messing with a host of fuel and spark issues first).
Answers
Compression. Have you checked the compression to make sure all cylinders are getting compression.
Fuel. Is it getting fuel? What is the fuel pressure?
Exhaust. Is the exhaust free flowing or could it be plugged?
Is voltage more than 12V on battery?
Is there any smoke? Engine compartment or exhaust?
Does engine crank faster than normal, normal or slower than normal?
Those are all questions to start with.
All that said, take a serious look at the crank position sensor.