Chrysler Repair: 96 Intrepid 3.3 V6 cranks wont start: code 54, digital multimeter, cam sensor

Question
Hello Roland: well, the Intrepid has been running flawlessly since you guided me to the repair on the last problem, however I have a new one. I think this car is turning into Christine! Last night, my girlfriend drove the car home, about 40 minutes drive. It started fine here. She stopped at a store for about 10 minutes then came out and it would crank but not start. FYI, it was about 8 degrees out then, if that has any bearing on things. After about 15 minutes it did start and run home. When it started, the check engine light stayed lit and set a code 54. This morning, it cranked but didn't start on the first try, but did on the second one. This is the first time for this issue to arise.

I checked the AllPar site for codes, and there were a few possible faults for code 54, but it seemed that the 'cam sensor' one fit best. I also searched on a 'crank-no start' failure, and found a few of your previous explanations for this sort of problem. I see that the cam sensor signal is tied to the fuel pump, so if the sensor signal is not present the fuel pump won't run. Is it safe to assume that it also won't run because without a cam signal the PCM won't know when to fire the spark plugs, since it won't know the position of the cam and valves? Can you advise how to test a cam sensor. I do have a digital multimeter, but no scope.

Thanks again and take care,

John

Answer
Hi John,
Yes, the cam will if failing, cause not a spark timing problem (which is handled by the crank sensor) but rather a fuel injector synch problem in matching which injector to fire when. You can test the cam sensor, but it would need to be tested in the failed (no start) condition. It probably runs fine when cold, but then breaks down when it gets warmed up. The orange wire will have 8V on it, while if you measure between the black/light blue and the tan/yellow wire while the ignition switch is in the 'run' position you should find that as you turn the engine over by hand via a ratchet on the crank puller bolt that the voltage oscillates between 5V and 0.3V several times per revolution. If not, then that would confirm that the crank sensor is bad.
From the symptoms and code I would believe that simply changing the sensor without testing it will solve the problem.
Roland
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