I switched my car over from maf to speed density. The car is an 85 and the harness is out of a 90. I believe that I got all the wiring correct but am now suspecting the vss as suggested by Rbob. I have the vss wire in pin k in my c207 connector running to pin b10 in the ecm connector. I have been reading elsewhere and have been told that it should be run to pin c6 in the ecm plug. The only thing confusing me is pin c6 is blank and b10 is labeled vss input. Do I have this wired correctly or am I wrong?

 

Pin B10 is for a magnetic VSS (sine wave).

Pin C6 is for a digital/optical square wave VSS. Which is what your '85 has for a VSS.

Remove the terminal/wire from B10 and place it at C6. Change the option flag for the digital input and change the VSS PPM to 2002.

RBob.

 

thanks so much for the help.