Looking at the diagram in the lower portion of Figure 1, you can see that the drawing seems to indicate that the mark on the crankshaft gear should be at the 12:30 position to line up with the timing mark embossment on the engine block. A technician used this diagram to set the engine as shown in the photo on the top of Figure 1.
The leading edge of the crank gear tooth top land is lined up with the timing mark embossment on the block. This orientation is incorrect. The mark on the block should line up with the trailing edge of the crank gear tooth top land shown by the red line in the top portion of Figure 2. Some service information systems state this in text and some do not. Do not use the crankshaft keyway as an alignment mark either.
The cam timing marks should be level across with the exhaust cam mark at the 3 o'clock position, and the intake cam mark at the 9 o'clock position. These cam marks are difficult to view visually straight on because of the angle of the small underhood engine bay opening on this model vehicle. Place a small pocket ruler directly on gears to align the cam marks to be sure they are in proper alignment with each other.
With the cam and crank gears all aligned properly, you should be able to use a lab scope to view the Crankshaft Position Sensor (CKP) and Camshaft Position Sensor (CMP) signals and get a pattern like the one shown in the lower portion of Figure 2. Using a lab scope is the preferred method to check the crankshaft and intake camshaft gear alignment. I am aware that though many Chrysler ECM/PCMs support a scan tool data PIDs labeled something to the effect of In Sync or No Sync, these PIDs are another example of, "It will tell you if it is bad but it will not tell you if it is good."This means if the PID says No Sync, there certainly is some kind of problem. However, the problem could be an out-of-time engine or it could be an erratic CKP or CMP signal. Even if the CKP and CMP sensors have individual PIDs, you have to realize that the PCM uses both signals to try and determine if one is missing or out of alignment. The PCM does not always correctly identify which signal is errant. Worse yet, if the PID reads In Sync, you might incorrectly believe there are no problems with the timing of the signals or the signals themselves. This is not so.
This PID sometimes is just wrong. Again, we need to use a lab scope to view both signals. Using a lab scope also beats tearing down the engine to check for problems.
Notice that this engine has a CKP sensor and a CMP sensor on the intake cam only. How are we to tell whether or not the exhaust cam is timed correctly? The first thing to check is engine vacuum, assuming the engine runs, because it is a quick and easy test. Most Chryslers even have an engine vacuum signal PID based the MAP sensor output. It is best to use a live gauge though as you might have a bad MAP sensor as the cause of an incorrect base fuel command and low engine vacuum.
If your live data does not match scan data, go after the MAP sensor. If the engine vacuum is low but your intake CMP and CKP signals are normal, you either are going to have to pull the front engine covers or use a pressure transducer in the spark plug hole and a lab scope in order to see if the exhaust cam is in time.Figure 3 is an in-cylinder pressure waveform from a PT Cruiser that ran poorly after a timing belt was incorrectly installed. Note that the exhaust pressure plateau caused by the exhaust valve opening is occurring late (retarded). The normal decrease in pressure that would occur at the end of the exhaust plateau due to the intake valve opening as the piston reaches TDC is too high as the piston movement is not evacuating the cylinder as well as it should due to the late exhaust valve opening.
Jim Garrido of "Have Scanner Will Travel" is an on-site mobile diagnostics expert for hire. Jim services independent repair shops in central North Carolina. He also teaches diagnostic classes regionally for CARQUEST Technical Institute.
