Is the PCM power relay activating? If yes, you should hear the fuel pump hum for 5 seconds when the key is turned to ON.
If yes, then check the crankshaft position sensor and camshaft position sensors to be sure they have output to the PCM.
The crankshaft position sensor:
- sends the powertrain control module a signal indicating crankshaft position.
- is essential for calculating spark timing.
Crankshaft Position Sensor (Integrated Ignition Systems)
The crankshaft position (CKP) sensor 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 powertrain control module (PCM). The trigger 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 trigger wheel, the CKP indicates crankshaft position and speed information to the PCM. By monitoring the missing tooth, the CKP 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 fixed reference (Figure 23) .
Camshaft Position Sensor
The camshaft position (CMP) sensor detects the position of the camshaft. The CMP sensor identifies when piston No. 1 is on its compression stroke. A signal is then sent to the powertrain control module (PCM) and used for synchronizing the firing of sequential fuel injectors. The Coil On Plug (COP) Ignition applications also use the CMP signal to select the proper ignition coil to fire. The input circuit to the PCM is referred to as the CMP input or circuit.
There are two types of CMP sensors: the three pin connector Hall-effect type sensor (Figure 20) and the two pin connector variable reluctance sensor (Figure 21).
A4 CHECK VREF VOLTAGE TO THROTTLE POSITION (TP) SENSOR
- Disconnect TP sensor.
- Key on, engine off.
- Measure voltage between VREF and SIG RTN circuit at the TP sensor harness connector. Refer to the schematic in Pinpoint Test DH .
Is voltage between 4.0 and 6.0 volts?
A17 CHECK PCM DRIVER TO COILS
- Connect incandescent test lamp between B+ and each coil driver circuit at the harness connector.
- Crank engine.
Does lamp blink consistently and brightly (one blink per engine revolution)?