Making the Cologne 2.9 Distributor-less using 4L OHV parts - TFI/SD to EDIS/MAF Conversion

[brokencase]

Brad's bracketry. Very nice.

I think you are good on pin 34. At least up to 93 ECMs if I read correctly.

https://eectuning.org/forums/viewtopic.php?t=17563

[DPDISXR4Ti]

I think you are good on pin 34. At least up to 93 ECMs if I read correctly.
https://eectuning.org/forums/viewtopic.php?t=17563

Nicely researched - thanks! '93 & '94 PCM's are interchangeable for the 4.0 Ranger, so I'm fine there.

I got a little concerned about pin#8 on the Ranger PCM, something that doesn't exist on the Scorpio. FWIW, it also doesn't exist on the XR4Ti. Some further research indicates that it's called the Fuel Pump Monitor. I then realized the '94 Ranger 2.3 PCM I'm running on my Brat, for years now, also has the Fuel Pump Monitor input on pin#8, and I've got nothing connected to it.

For those that care, here's the technical details on how the input is processed, if it happens to get it. If it doesn't get any input, there's no effect on operations.

Yes it is a bias voltage, internal to the engine computer the fuel pump monitor line is supplied with battery voltage which passes through a high value resistor ( thousands of ohms) before it reaches the outside of the engine computer. The internal resistor inside the engine computer is roughly equal to the resistance of the inertia switch LED warning light. This why your meter shows roughly 1/2 battery voltage with the inertia switch tripped.

By reading the voltage at this point the engine computer can work out if there is a supply circuit failure (for example fuse or relay) or a short to ground or the inertia switch has tripped .

A way to make sense of this is to work out or test what voltage shows on the FP monitoring wire in normal running and when all the possible fault conditions occur and note these down to make a table. The fancy name for this is a Truth Table.

[brokencase]

Brad- What about bank fire versus sequential?

The Scorpio fires banks of 3 injectors at a time. But are not the later Rangers sequential? I think than means wiring to the injectors is different?

[DPDISXR4Ti]

Brad- What about bank fire versus sequential?

The Scorpio fires banks of 3 injectors at a time. But are not the later Rangers sequential? I think than means wiring to the injectors is different?

Except for CA, SEFI didn't happen until 1995 with EEC-V. That's one of several reasons why I opted to stay with EEC-IV.

If this all works out well, I might opt to go EEC-V down the road and replace the entire harness. I can see that becoming an issue given the fragile nature of the small gauge wire Ford of Europe used on these cars. Don't hold your breath.

[DPDISXR4Ti]

Polarity matters for the VR sensor. The typical donor sensor (indeed, the one I'm using) and harness comes from a SPI 2.0 engine as found on the 90's Escort/Tracer or early (2000-04) Focus, but the wire colors are not the same on those two applications. I have both pig-tail clip-offs here, but I'm not sure which is from which donor, so I'll provide both as reference.

The positive (+) is blue on one harness (probably the Escort) and white w/ red stripe on the other (I think the Focus).

These two VR Sensor wires go directly to the EDIS module. Inconveniently, the harness for the EDIS module has the blue wire as negative (-) and the gray as positive (+). Many have made a mistake here, especially if using the sensor harness which has the blue wire. No harm will come to anything if hooked up wrong, but the sensor output will not happen.

[DPDISXR4Ti]

Making the final changes. At the PCM harness connector, all that's needed is to add circuits 14 and 15 for the MAF. I also added #4 for the EDM/IDM signal. For now, it's not connected to anything.

I also moved wire #46 to position #44

20240801_113832.jpg (401.46 KiB) Viewed 2574 times

20240801_120550.jpg (357.77 KiB) Viewed 2574 times

[DPDISXR4Ti]

First test... I have spark. I have fuel pressure. I got it to briefly start with ether.

I presume the fuel injectors are not getting commanded to open. Hmmmm...

1992RangerEEC4-Schematic-1.jpg (104.46 KiB) Viewed 2573 times

1992RangerEEC4-Schematic-2.jpg (112.2 KiB) Viewed 2573 times

1992RangerEEC4-Schematic-3.jpg (128.32 KiB) Viewed 2573 times

1992RangerEEC4-Schematic-4.jpg (107.39 KiB) Viewed 2573 times

[DPDISXR4Ti]

I presume the fuel injectors are not getting commanded to open. Hmmmm...

Confirmed this just now with a noid light - no light at all during cranking. (i.e. No power to the injectors during crank)

More info, which I initially thought was telling me I haven't got something right... With KOEO, I'm getting 12V on BOTH sides of the injector harness.

Edit... Just found this - I guess it's actually normal
If all of the injectors are plugged in...and you pull the plug off of one injector, you will have 12 volts on both sides of that plug. This occurs because the injectors are batch fired and they are electromagnets. <On a V8 engine> The 12 volts on one side "bleeds" through the electromagnetic coils on 3 of the injectors and four of the grounds are shared...resulting in 12 volts at the disconnected plug.

[DPDISXR4Ti]

So in summary. I'm getting 12V+ to the injectors as I should. What I'm not getting is the switching to Gnd via pins 58 & 59. Both the Scorpio and Ranger PCM's are wired exactly the same in this regard - nothing changed. Gotta be something deeper than that. Hmmmm...

So where do circuits 58 and 59 actually get their grounding? Is it pin 44? What if the schematic has a typo and it's actually pin 46, as it already was on the Scorpio? Checking my 1994 Explorer schematic, it's pin 46 there.

[brokencase]

I wonder if the EECIV is sensing something else is wrong and that is why it won't fire the injectors.

You know, like when you hold the pedal all the way down on a Ford it goes into clear flood mode and doesn't fire the injectors.

Double check TPS connections. Or perhaps fuel pump relay input to the EECIV.

Also - if there is something wrong with the EDIS signals it might not fire the injectors.

[DPDISXR4Ti]

I wonder if the EECIV is sensing something else is wrong and that is why it won't fire the injectors.

I've definitely considered that. In fact, I tried another TPS and re-checked the connections just in case. No change.

Or perhaps fuel pump relay input to the EECIV.

I am getting the 2-second fuel priming cycle and pressure at the rail, so I think that's all good there.

Also - if there is something wrong with the EDIS signals it might not fire the injectors.

But I am getting spark, and it did start for a second with ether.

So I went ahead and moved pin 44 back to 46. No change at all. No pulsing of the injectors.

I wish I had another PCM to try - this one is untested. I do have one from a 5-speed '91 Explorer which requires some pins to be moved around. Not a huge deal. I have spares of so many other things, but never came up with a spare Ranger PCM.

Just thinking now, I'm realizing I still have the MAP hooked up as a MAP. It should open to atmosphere now as a BAP. But I can't envision that an incorrect signal there would shut the injectors down. At start-up it's essentially at atmospheric pressure any way.

[andyofcolumbusmerkur]

The distributor is missing, that must be the problem. Let me check with ai. Yep you need a distributor to make it run.

[Ed Lijewski]

Check for trouble codes?

YMMV

[DPDISXR4Ti]

A couple more reference docs - these are for a '91 Explorer and '95 Aerostar, but they're pretty much the same. These both indicate pin 46 is Signal Rtn, which is what I've heard from the EEC Tuning Forum. I'm going to study these so that I can move any pins so that I can run one of these PCM's (I have both)

1995Aerostar-EEC-Schematic-ezgif.com-webp-to-jpg-converter.jpg (248.73 KiB) Viewed 2420 times

1991 ExplorerPCM-Pinout.jpg (112.08 KiB) Viewed 2420 times

[brokencase]

Brad - Just so I am clear on everything...

I presume you are using the stock Scorpio harness to connect your Ranger EECIV (making pin swaps and running additional wires as mandated to support EDIS and MAF)? Correct?

If this is the case then I would look at the Scorpio EVTM EECIV diagram and compare PIN for PIN with the first set of diagrams you posted.

Making a spreadsheet with the with the pin numbers/function in two columns side by side is useful. I did something similar when I was comparing the SHO EECIV with the Scorpio's

Pulling codes may also help troubleshoot.