Engine will not engage

ZEHKIRE

MEMBER
2003 FORD RANGER
4.0L
6 CYL
4WD
AUTOMATIC
110,000 MILES

For the third time in a month I have had to take my truck in for repairs. Have not had to do this in years with an annual maintenance check. First time, check engine light came on. Mechanic determined it was the PVC vacuum. A week later, engine would not start. Battery is new, but turns on everything. Lights come on, radio on, fan runs, AC runs. Dash lights up fully. Turn key to start the engine, starter kicks on and cranks the engine. Engine does not engage. Let it sit a while, and tried again, but again nothing. Towed to mechanic. After they ran diagnostic it was determined the fuel pump was out and got replaced. A week later, same thing exactly. Left for vacation and came back to it working. Few days later, engine stalls out twice on me while driving. Engine just cuts out and I coast. Stop the truck, restart engine no problem. The next day however, same story, does not engage. Exact same thing as before, everything comes on, engine turns, but no ignition.

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning.

From your description, it sounds like a crank sensor may be failing.

Roy

The crankshaft position (CKP) sensor (Figure 56) is a magnetic transducer mounted on the engine block adjacent to a pulse wheel located on the crankshaft. By monitoring the crankshaft mounted pulse wheel, the CKP is the primary sensor for ignition information to the PCM. The pulse wheel has a total of 35 teeth spaced 10 degrees apart with one empty space for a missing tooth. The 6.8L ten cylinder pulse wheel has 39 teeth spaced 9 degrees apart and one 9 degree empty space for a missing tooth. By monitoring the pulse wheel, the CKP sensor signal indicates crankshaft position and speed information to the PCM. By monitoring the missing tooth, the CKP sensor is also able to identify piston travel in order to synchronize the ignition system and provide a way of tracking the angular position of the crankshaft relative to a fixed reference (Figure 54) for the CKP sensor configuration. The PCM also uses the CKP signal to determine if a misfire has occurred by measuring rapid decelerations between teeth.

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