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2005 Jeep Wrangler hard to start, pulls up cam sensor and map sensor code. After cranking for several seconds it will finally start and idle fine , replaced cam sensor, tested fuel pressure, even replaced the computer with a store-bought plug and Play. It shows no 5 volt reference to the cam sensor, so I did a pinout to the computer harness 5 volt pin , and when I run a jumper wire from that 5 volt pin from the computer, I touch it to the 5 volt reference wire to the cam sensor to see if it would start normally, but no deal. When I jump The wire the voltage drops to 0 on that 5 volt reference, until I take the wire off. I have checked schematics and diagrams five or six times to make sure I have the correct wires before I started this process, any help would be appreciated
You may want to check wether the reference voltage is shorted to ground. If indeed there is a short disconnect one sensor after another while watching the voltage supply to the sensor until the short goes away.
Sometimes the diagram will not show all sensors that share the same reference voltage/power supply. If a short is still present after disconnecting all sensors that may share this power supply then check that the wiring isn't shorted to ground.
If there is no short neither then the pcm may be bad. You can test this by cutting the wire supplying the 5V reference at the pcm side and recheck for voltage on that cut wire. As you already changed the pcm this wouldn't be my main suspect though.
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