PT Cruiser No Spark
Mac’s question:
“PT Cruiser ran hot. repaired mechanical. ran 5 minutes and lost spark. any ideas?”
Answer:
Now it depends upon how hot the engine got. If it got really hot, it could have melted the crankshaft position sensor. With no crankshaft sensor, you’d have no spark. Now pt cruisers have had LOTS of problems with their ignition coils, which may be damaged further by an overheating engine. I change out a lot of ignition coil packs on pt cruisers, so check to see if power is going into the coil, and not coming out to the spark. If you’ve got power going in, and none going out to the spark plugs, then the coil has gone bad. Good Luck,
“thanks for the answer. I’ll remove the sensor. is there any way to check it at home? Coil checks good on bench, but who knows. thanks again”
It’s a magnetic induction sensor, and the only true way to test it is to leave it on the engine and check the waveform it produces on an oscilliscope as you crank the engine over. Here’s some tech info, you could check the five volt reference but that’s about it without an oscilliscope: The PCM uses the Crankshaft Position sensor to calculate the following: Engine RPM TDC number 1 and 4 Ignition coil synchronization Injector synchronization Camshaft-to-crankshaft misalignment (Timing belt skipped 1 tooth or more diagnostic trouble code). The PCM sends approximately 5 volts to the Hall- effect sensor. This voltage is required to operate the Hall-effect chip and the electronics inside the sensor. A ground for the sensor is provided through the sensor return circuit. The input to the PCM occurs on a 5 volt output reference circuit that operates as follows: The Hall-effect sensor contains a powerful magnet. As the magnetic field passes over the dense portion of the counterweight, the 5-Volt signal is pulled to ground (0.3 volts) through a transistor in the sensor. When the magnetic field passes over the notches in the crankshaft counterweight, the magnetic field turns off the transistor in the sensor, causing the PCM to register the 5-volt signal. The PCM identifies crankshaft position by registering the change from 5 to 0 volts , as signaled from the Crankshaft Position sensor. Good Luck, now you know how complex modern vehicles can be.