Per your question in a previous reply, if the engine is running, the cam and crank sensors are working, so there is no need to check them. It is only when spark and fuel pump / injector pulses are missing that you need to determine which signal is missing.
I must clarify that you can have a crank / no-start due to loss of fuel pressure, loss of spark, or most commonly, loss of both. If you find you have no spark, do not waste your time working in the fuel supply system, but, understand there is going to be fuel pressure because the pump will still run for one second when you turn on the ignition switch. You are not likely to have a separate spark-related problem, and a fuel pump-related problem, at the same time. Also, if you have a failed fuel pump, you can be pretty sure you are going to have spark yet.
It is easy to tell if you have no spark or you have no spark and no injector pulses by simply observing if there is a heavy gas smell at the tail pipe. No gas equals no injector pulses or no fuel pressure, and when you have either of those along with no spark, you know you need to look at what both systems have in common. That is both systems are turned on during engine rotation, (cranking or running), and the engine computer knows that by the signals it gets from the cam and crank sensors.
Wednesday, December 21st, 2016 AT 10:35 AM