It "tells" the computer the rational location of the distributor for spark timing.
it can be the rotor or the distributor cap and it could also be a bad electrical conection.(your "feed" wire).
Inside the distributor
Inside the distributor.
its inside the distributor.
I'm having the same problem with my 1988 dodge b350 5.9L. I've also replaced all that stuff. Next on the list to replace is the distributor itself. One thing I know for certain, make sure that gap in the pick-up coil is right or you'll be trying to start the van in vain.
No crank sensor on a 1990, only the pickup plate (cam sensor) in the distributor. how about a 1991?
It is the pick up plate inside the distributor.
change distributor cap and rotor
1-3-4-2 Distributor rotates clockwise.