Mercruiser/Motorola versus Stand Alone ECM's

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
43,287
Grounding a relay to see if something works is ok, but don't keep them there. Need to find out why a ground is needed.

What plug?
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
43,287
It's on the side of the distributor...
That is the CAM sensor and Merc didn't use it with some 555 ECM and did use it with others. Yours should be plugged in

This is what you should find
B1 Ground splice 100 Blk/Pink
B18 12V wake up power from key
B21 +5V splice 101 Gray
B23 EST coil control

Pink/White 12V to coil

CPS and CAM sensor.jpg
 

njh1

Cadet
Joined
Nov 8, 2020
Messages
28
Hmmm...cam sensor?
Do they use the distributor drive as a cam sensor? Thanks for that i would never have guessed!
So..
I have tried both ecm's...neither provide an earth for the MPR and cosquently it wont fire, There's no spark whatever I try but power to the Coil Module and driver module...can i assume they are no good?
Can I also ask is the fuel pump suppossed to cut off at a certain pressure. I have opened the Shraeder valve and greeted with a good spray of fuel...is that controlled by the ecm as well?
What a day of rain dodging and testing...
 
Last edited:
Top