b13 ga's had it stamped and b14's didnt have it stamped. KA, CA, RB's had the eccs stamped on the intake plenum aswell.
Engine Computer Control System
I copied this from Wiki Answers:
*- Also regarding Nissan 720 p/u Z24, ECCS can stand for Electronic Concentrated Control System ( I know 85's have this & 84 Calif. mod not sure what other years). System function is to control the fuel/air mixture at carb, it consists of following subsystems and components: spark plug switching control (switchs from 4-8 active plugs when needed), fuel shut off control (shuts off fuel during deceleration), fuel mixture heater (fitted under carb to heat fuel for better vaporization/burn), air fuel ratio control solenoid ( located in carb is the actual air/fuel mixer, different voltage inputs cause it to stay within certain values 14.7to1 I think!), O2 sensor, H2O temp sensor, throttle valve switch (located on side of carb sends throttle points to computer), vacuum switch on Int. manifold, clutch switch, neutral switch, inhibitor switch(A/T). On Z20 engines the ECCS incorporates a detonation sensor subsystem ( senses engine knock/ compensates). I've been unable to find a wiring diagram for insides of this control system nor any testing instructions, unit has one green light on side facing engine, I've yet to attempt checking it for any diag. codes (most of these units have a red and green light, however this year/model has only one green, will check it for slow/fast blink codes and update as needed. Sorry got carried away, toomuch info perhaps, but I like to be thorough.
check out
ECCS • Index page
Its a forum dedicated to Nissan ECCS Engine Managment.