Walter

i'm messed about this topic.. i know that the ignition is controlled through distributor and too the cam gears, right? then , how does the ecu control the ignition? (i just learning the fuel and ignition maps )

Guy-Fast

Notices all the wires comin out of the dist. they go to the ecu

Chris Harris

ECU = Engine Control Module

leed

Ever notice that the rotor in the dizzy has a long trailing contact edge? This is to account for the varying ignition trigger points controlled by the ECU. The dizzy is just a mechanical means of directing the spark to the appropriate cylinder when its firing order comes up. The ECU determines the exact crank degree for firing.
Also, the reason why you can unbolt and adjust the dizzy is because the sensors that the ECU uses to determine the crankshaft position is located inside the distributor; which allows you to sync the physical sensor pickup with the ECU.

HTH,
Dave

Walter

so, though the long trailing is contacting with edge , could b that there be not spark until the ECU decide if there are spark or not, right ?

Guy-Fast

Lets play a game



Go unplug the big plug on the dist that goes to the ecu



Now go see if you have spark

Walter

what plug do you refer?



that with a lot of wires ?

Guy-Fast

yes

Walter

mm i see, so ,trhough this plug , pass the spark to a determinate time (advance or retard timing), right? but i have seen that you can to move the distributor for advance or retard the timing... i think this topic about distributor,spark,etc is very difficult to understand