I have a good question for you engine management pro's

[makaveli200369]

For early 90's cars that have fuel injection but still have a distributor how in the world does the ECU control ignition timing? There was no vacumm or electronic devices in the distributor that allowed it to move around. And if the ECU retarded or advanced when it sends the signal to fire the one main coil I do see how it would sych up with the rotor/cap and points.

Meaning lets say its a 6 cylinder distributor and every 60 degrees the rotor connects each cylinder to the main coil as it spins around. If you retarded or advanced the ignition timing from the coil...the rotor could be delayed or advanced past the time window which it has the ability to transfer the electricity from the rotor to the points.

I must be missing something...

 

[bansheebuzz]

the rotors on systems like this usually have a very broad tip to allow for the differance in timing.

 

[mshawari1]

the rotors on systems like this usually have a very broad tip to allow for the differance in timing.

Make it clear for me !! how it is work in the ls400 exactly ​

 

[sideshow]

the crank senosrs and cam sensors have no movement like in old dizzys

where they have bob weights for mechnaical advance and vacuum advance


new ecus have a sort of locked dizzy or crank and cam sensors thta are fixed

when u wire up aftermarket ecus u usually have to set the dizzy or crnak sensors up say at around 50 degrees before top dead

the ecu has a sort of preset timng figure inside

take the autronic smc u have to set it at 60 degrees befor etop dead

this means the ecu knows that to do the timing it has to add 60 plus the actual timing needed

so at 60 degrees before top dead the ecu gets trigger to fire the spark then allows crank to spin 40 degress to fire at 20 degrees if timing is at 20

so end of day the ecu gets the trigger to fire way before the actual firing time

its hard to understand if u do not have much experience with many aftermarket ecus so hope this helps abit

 

[mshawari1]

Thanks
I got it

 

[makaveli200369]

That is true the rotor does have a broad tip. Which I can see allows contact for to 10-15 degrees of rotation. And since the cam spins half the speed of the crank 10 degrees there would equal 20 degrees at the crank. Thanks