I'm hoping there is a Ford tech on here that can tell me where to pick up a reliable square wave RPM signal I need for a controller. I am installing a Snow Performance stage 4 boost cooler on my 2018 Explorer Sport. In order for this stage 4 system to work properly, it needs a boost and an RPM reading to meter the amount of injection. Using the ground at the #1 coil gives no signal. Using the PCM (trigger) for the #1 coil produces a signal but will make the tach on the controller run backwards. I even installed a MSD DIS tach adapter with an analog tach with the same result. I don't have schematics so I'm at a loss. So, where does the PCM get its RPM data from and is it a square wave signal? Is the CKP or one of the CMP's a hall effect sensor and which wire is the SIGRTN for the PCM than I can connect to for a tach signal. Thanks in advance.

 

For starters ,,,,,,,,,,,Fords do not like add on components. What that means is, you could be interfering with signals, come up with problems and not know why.

RPM is derived from crank sensor signals and I guess if you spread the signal out far enough on a scope you might get a square wave, not sure.

Maybe someone will come up with a better answer.
Some cam sensors will produce a square wave, but that tapping in can cause problems.
Let's put it this way, if you do tap in for a signal and have no problems ,great !

 

Thanks Hanky. The controller doesn't change the signal voltage in any way it just monitors it. It is no different than using an oscilloscope. I was just hoping that one of you guys is a Ford tech that wouldn't mind looking up the schematic at work and giving me the wire color and PCM pin location. I guess I'm gonna have to grit my teeth and buy the manual.

 

You might try "Helm inc".

Print as well as electronic publications usually are available..

 

I ordered a factory dealer disc after your last message. I found a partial schematic online today and it looks like the pcm is getting combined rpm data from the ckp and both cmp sensors and there was a pcm connector pinout. After I get through road running in the morning I'm gonna put my oscilloscope on the pin and see what kind of signal is going to that terminal. Just sucks because the Cowell has to come off to get to it. I'll post what I find in case someone else is having the same issue.