engine rpm sensor?

[camccardell]

ok, I am looking at a wiring diagram for an 94 f350 ecm pinout. It says that it has an engine RPM + and -

I would assume that these are either a positive and a ground or the 2 sides to a sensor of some sort.

Is this the same a crank sensor? I am trying to figure out what the computer is looking for.

Thanks

[camccardell]

too late to edit...

What I am trying to do is use an ecm from a 93 f350 on my 95. Only diffirence is that I am putting ona 4bt and I want my trans to be able to shift properly.

I guess the rpm sensor runs on the injection pump gear. I would imagine (and I could be wrong) that the inj pump gear is the same size as the cam gear?

Well if the cam spins 1/2 rotation for every complete rotation of the crank, I would just need to put a plate on the crank with 1/2 as many teeth right?

Anyone know how many teeth are on a 7.3l injection pump gear?

Any info or links would be appreciated!