I’m looking for a complete pcm/ecu pinout diagram for a 1993 ford ranger 4.0 auto (just a complete wiring diagram off of the harness of the computer)

if anyone has anything I would much appreciate it

 

1993/94 4.0l were exactly the same, PCMs are interchangeable for these 2 years

 

Thank you so much!

Dumb question but are the ICM and PCM wires on the picture coming out of the computers same connector/harness? or are they separate chips?

Also it’s saying there’s “coil A coil C coil B” going into the ignition coil, and I just want to double check the ignition coil is the EDIS coil where the spark plug wires going to the plugs plug into correct? because my ranger doesn’t use multiple coils or a distributor so I just want to make sure

 

Yes, pre-1995 Rangers all used separate Spark modules, the 4.0l used the EDIS-6 module, 3.0l used TFI module, 2.3l used ICM, but ICM(ignition control module) "name" could apply to all 3

This separate EDIS-6 spark system was connected to the Crank sensor and to the Coil pack, which has 3 coils inside it, each coil sparked 2 spark plugs at the same time(called Waste Spark system)
Its an autonomous spark system, and its used as is to start the engine, it also has internal RPM advance
But what it doesn't have a Load Spark Advance(Vacuum Advance), as air/fuel ratio changes when engine is under a Load spark advance also needs to change, since the PCM controls the fuel system it has a wire to the EDIS-6 module called the SPOUT wire, it relays engine Load to the EDIS-6 so it can adjust spark timing

The EDIS-6 also sends Crank sensor pulses to the PCM so it can time fuel injectors and has the current RPM/Tach signal, of the engine, and PCM can then calculate air/fuel mix so it can send back a valid SPOUT signal


1994 and earlier PCMs were 60 wire(EEC-IV), in 1995 and up Rangers got the newer 104-wire PCM(EEC-V) that had internal spark control system

The coil pack wiring reflects the 2 spark plugs that need to be sparked at the same time, this is from the way the engine is Balanced internally
3 4
2 6
1 5
front

3/4 are sparked at the same time
as are 2/6 and 1/5
Each Matched Pair is at Top Dead Center, at the same time to balance the engine
The 5 6 4 side often get miswired, lol

 

Thanks that’s all really good to know! with the coil having three internal coils being said, the other thing I was wondering is if the coil (for the EDIS-6 spark system) is considered a single or twin coil in general? (if I were to buy something that requires a single coil to work wiring wise)

also I doubt it but I’m just making sure the coil doesn’t have an externally attached amplifier correct?

my only other concern is finding the right coils positive and negative, because from the diagrams you sent me I found the coil ground which looks to go from the PCM to ICM but I’m not sure where those are unless it would just be at the computer wiring harness I’m assuming?



and then is the positive coil wire red & light green? (that’s the only related one I could find on the pdf which goes from computer to coil plug, I will attach a pic at my coil)

Is this 12v positive to coil?

 

Each of the 3 coils in the one pack shares the one 12volt wire, 12v wire has a Condenser/capacitor connected to it to prevent AM Radio noise
Then 1 ground wire from the EDIS-6 to each Coil in the coil pack
There are no "coil amplifiers"

Any ignition coil works the same way, primary coil inside gets 12v and Ground, this creates a magnetic field around the secondary coil inside, also a low amp high voltage in secondary coil
When the Ground is removed by the EDIS-6 on one of the coils the magnetic field holding the low amp high voltage in the secondary coil is released, causing 2 spark plugs to "fire"/spark
Ground is reconnected and new "spark" is created in secondary
All 3 coils in the coil pack work the same way, via pulsed ground to each primary coil
EDIS-6 times the grounding and unground of each coil to spark engine in its "Firing Order"

The ground wire between EDIS-6 and PCM is there for reference, the timing signals between EDIS-6 and PCM need to be exact so they need to "share" a common ground so both are "on the same page", vehicle grounds can be unreliable which can be a pain when working on lights and other electrics, but would be a BIG PAIN if engine didn't run well, lol
The PCM doesn't control the Coil Pack at all, PCM just does fuel mixes, it controls fuel injector open times
PCM does send spark "timing" suggestions to the EDIS-6 for Load spark advance only

Many Hot Rodders use the EDIS-4, EDIS-6 and EDIS-8 for spark control on custom builds because they are stand alone spark systems, don't need the Ford PCM at all

 

That all makes sense ty, except that’s bad news for me lol if you’re saying the coil ground wire is internal so there’s no way to splice into it? and if the ground wire to PCM I was talking about doesn’t do anything are you saying the timing signal wire would be the wire I would use instead of a regular ground wire? (if it doesn’t have an external accessible ground wire) if so what would the timing signal wire be called in the diagram? I couldn’t find one

Basically all I want to do is connect this to the coil

 

That could work on 1 of the coils in the coil pack, but not sure if that would help you if one coil cut out at the REV limit you set, you should notice it, but not like losing all spark

And there is another issue as well, the issue of "spark count" for RPMs

V6 with a single coil has 3 sparks per 1 RPM, and REV limiters are like Tach's, set for 4, 6 and 8 cylinders based on spark count

V6 Coil Pack has only 1 spark per coil per 1 RPM, so 3 total but if you hooked a Tach to one coils ground wire it would read 300RPMs when engine was at 900RPMs

So if you wanted a REV limit of 6,000RPM you would have to set the limiter at 18,000RPM if hooked to just the one coil in the coil pack
If you could set REV limiter for 2cyl engine, that might work, 1 spark per RPM


The EDIS-6 does have a Tachometer output, the IDM wire, tan/yellow wire it runs to the PCM but also to the cluster's Tachometer, you can see a "DOT" on that wire, thats the splice to Tachometer

If you could find a REV limiter Tach has had some type of on/off external connection you may be able to use that to cut 12volt to coil pack, not sure if thats a good idea or not, REV limiter usually just Grounds the coil full time so no spark

 

Good ideas thanks for the suggestion! I wish there were more options for rev limiters but it seems to be pretty slim pickins lol unfortunately, and most rev limiters are very limited as far as what they can do but funnily enough the omex limiter actually goes up to 20,000 RPM and has 2cyl support I just wouldn’t know where to plug it in if it’s only using one of the coils but if you know please lmk!

I’ve also seen videos of people wiring a push button to their coil to manually make it sound like it’s banging off a “limiter” and backfire etc same idea as revving a dirt bike and doing the kill switch trick, I forget how they wired it but since the ranger needs a constant 12v while it’s running it would be tricky to interrupt that with a push button or maybe not even possible? I would need something like a momentary push button except reverse where it disconnects the circuit when it’s pressed rather than connecting it, maybe a relay or something I’ll have to look into it

 

With the advent of computer control of engines and distributorless spark systems REV limiters became software based
But 1994 and earlier used the EEC-IV Ford computers with no spark control, and the EDIS-6 doesn't have addressable software as far as I know

There is a product called "Megajolt/E MK2" that says it works with EDIS-6 modules and gives full control of spark settings and has a REV limiter, made to be stand alone spark system
So not sure it will work with current PCM, might be worth emailing them to ask

 

thank you so much I would have never found that on my own and I’m seriously considering buying one once I find out it’s compatible or not with the PCM. I wonder if the program for windows is difficult to figure out for the first time set up, I’ll have to do some research

 

So unfortunately it won’t work with the PCM, which makes sense why. The only other ignition box compatible I found was the MSD DIS-4 but they’re $800 and they’re out of my price range even for used ones on ebay but I’m still looking lol