Why does the Aerostar use an external EDIS-6?

[DPDISXR4Ti]

I stumbled across an early 90's Aerostar in the junkyard the other day and noticed that it uses an external EDIS module whereas the Ranger has the EDIS ignition logic built into the PCM. Does anyone know why Ford did this? It's pretty much the same 4.0L engine in either platform so it's surprising to me that they did the ignition two different ways.

 

[snoranger]

What year Ranger are you talking about?

I can assure you both my 90 Ranger 4.0L and my 95 Explorer had separate EDIS-6 modules.

 

[holyford86]

What year Ranger are you talking about?

I can assure you both my 90 Ranger 4.0L and my 95 Explorer had separate EDIS-6 modules.

To also build on this, all OBD1 4.0 engines used an external EDIS6 module, it went inside the PCM with OBD2

 

[DPDISXR4Ti]

Just getting back to this thread.... Hmmmm, I must be loosing my mind. I pulled a complete harness out of a '92 4L Ranger and I thought for sure it did not have an external EDIS module. Maybe someone had already removed the module and so I just have a vacant quick-connector where the module would have been attached?

Where would the module be located in the engine bay? I need to study more on my next junkyard visit.

Thanks for the input.

 

[ThatOneGuy]

Just in front of the battery on the core support.

 

[RonD]

+1 ^^^

Can be on the front of Rad support as well, that's were it is on my 1994, mines on drivers side

To answer original question, all Rangers have external spark modules thru 1994
In 1995 Rangers got the newer 104 wire EEC-V computer, the new computer had internal spark modules

The earlier EEC-IV 60 wire computers did not
Any Ford model with the 60 wire EEC-IV would have external spark module, not a Ranger thing

Any car makers 1996 and up vehicles were suppose to all have the newer computers, by law, and had to use OBD2