EA82T ECU 3-plug/4-plug dizzy differences?

[steptoe]

someone mentioned elsewhere that the EA82T ECU were either 3 plug or 4 plug , and that the 4 plug runs the dizzy curve


so what is different in the dizzies and how do tell difference on inspection ?

I would think 4 plug has no counterweights advance bits ?

[Gannon]

Yeah your right about the counterweights

The 3 plug/ flapper afm/ 84-86.... call it what you like, the ecu only controls the fuel injection. The spark advance is controlled directly by the vac and mech advance units in the bottom of the disty. (except the turbo models have an external knock unit that delays the signal between the ignitor and the coil)

The 4 plug/hotwire afm/87-94 models,.... the ecu has maps for both fuel and spark, so the disty has no internal advance mechanism. The bottom of the disty is just an optical crank angle sensor. Im pretty sure that the plug is a rounded square shape and has 4 wires.


Hope this helps


Gannon

[steptoe]

hmmm mine is 87 turbo and has flapper style I think (might contradict your info above) needs further investigation who knows what has happened in 19 years anyway !!

[Gannon]

Mmmmm, there were a few 87 cars that used the 86 wiring loom, but some if the plugs are like that of the 87 models, must have been some leftover 86 looms in the factory when they started producing the 87 line.
Its confusing and hard to diagnose as there are a few variables.

Have you checked your ecu? try to fing out how many plugs are connected into it. That is a sure fire way to find out what system you are using.


Good luck

[Suby Wan Kenobi]

If you got a flapper you have a 3 plug ECU you can also tell with the Dizzy as the 3 plugs have stuff in them while the 4 plugs where gutless

[SCOOBIDOO]

someone mentioned elsewhere that the EA82T ECU were either 3 plug or 4 plug , and that the 4 plug runs the dizzy curve


so what is different in the dizzies and how do tell difference on inspection ?

I would think 4 plug has no counterweights advance bits ?

Flapper type is a rising edge rulucter ,type distributer giving out a sine wave to the internal module,also has vacuum advance and counterweight centrifugal mechanical advance.
4 plug ecu dizzy is a photosensitive diode type pick up with 360 increements for crank position and 4 sync increements , hence the four wires... this dizzy is not mechanically or vacuum advanced...all ecu controlled...this type of sensor also puts out a square wave unlike the sine wave sent from a relucter to module type...cheers.

[steptoe]

alright , thanks. my dizzy has guts. any qik tip on ecu look at or removal

(i HATE inverted incline double twist getting under dash)

[SCOOBIDOO]

undo your bottom cover it is directly unde the column....if your dizzy has stuff in it ill bet a $1000 bucks it has 3 plugs. and a flapper door..cheers