Hello all, new member here. Thanks in advance for any advise. I'm pulling my hair out on this one.

'16 F150 Ecoboost, cranking no start. No codes. Scanner shows rpm, 175-200. Scanner also says cams and crank are in sync after you start cranking it. Fuel pressure, low and high side, actual and desired match on scan data. Fuel quality test is good, too. I have spark, but it is very random, not normal. I think it's going into FMEM. I pulled a plug and can see injector squirting as well. Checked compression on that cyl, 120psi. Running out of options, so I started scoping the cam sensors, all have a nice square wave. Then I scoped the CKP at the PCM, this is where it gets weird. The signal wire has 5v on it at all times, start cranking and it has random down spikes. How can I have RPM on scanner with this "signal"?? According to CKP testing, I'm not supposed to have any voltage on signal wire with sensor unplugged (Test JD13 for Fords CKP test procedure). So I get time to access sensor and test. Remove and Unplug sensor, have good VREF and SIGRTN, KOEO and cranking, and have 5v on signal wire. Unplug PCM, check to test if signal wire is shorted to VREF, it's not, no continuity. And with PCM unplugged, 5v on signal is gone. Plug PCM back in, 5v is back on signal wire. Cut signal wire near PCM, no more 5v on signal wire sensor side, but sill has 5v on PCM side of cut wire. PCM internally shorted to 5v it on pin 11 it seems? (PCM Connector C175E). Used video scope, tone ring looks ok. But even a bad tone ring wouldn't cause there to be 5v on the signal wire all the time.

So with no more bias 5v on signal wire, I figured I should get a signal on the crank signal wire up to where I cut it. So I scoped it and there is nothing at all. 0 volts. Even tried a new Motorcraft sensor.

Thanks everyone.

Tyler Grant
Technician
Tony's Auto Service
Phoenix, Arizona, USA