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January 1, 2001
Ford’s Distributorless EDIS Ignition System
If there’s one thing I’ve learned over the years, especially the last few, is that technology is our friend. But of course that statement only applies when things are engineered correctly and working properly. I’ve spent many an hour pulling my hair out in front of a computer monitor.
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| Here is the heart of it. The EDIS-8 module and 12 pin connector with 10" of wire. Both are still available from Ford and will retail for about $230.00 for both. |
This past summer we became intimately familiar with the EDIS ignition system and immediately fell in love. The EDIS ignition system began appearing in the late 80’s on Fords that were distributorless. There were earlier units that were called DIS but we’re going to focus on EDIS which appeared to be Ford’s standard ignition control on EEC-4 cars sans distributors until about ’95.
Then in ’96 the EDIS module’s functions were incorporated into the EEC-5 computers with its 104-pin connector as opposed to the EEC-4’s 60-pin connector. The basics of this system are quite easy once you get used to it. It consists of the EDIS-8 module (or EDIS-4 or-6 if it’s a four or six cylinder). The 12-pin connector for the module, a 36-tooth trigger wheel missing one tooth, trigger pick-up, respective coil packs and related wiring.
As of now, this system outside of its original OEM setup only works with an aftermarket fuel injection system such as "Speed-Pro". We’re confident it will be adaptable to other aftermarket fuel injection systems and we’re even going to try to run it with the popular A9L ‘89-’93 Mustang EEC-4 computers in the summer 2001.
The system is relatively easy to wire and its operation is quite simple. In a nutshell the module gets a crank trigger and position signal from the trigger wheel and then the EDIS-8 module organizes the firing order and triggers the coil packs in the proper order. It’s considered a "waste spark system" meaning that it fires at compression and exhaust strokes near TDC. As long as you organize the wires accordingly, it could conceivably run any firing order you want on a typical 4-6 or 8 cylinder.
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Here's a replacement timing cover from Ford. Although its not the Explorer pc which is based on the SN-95 timing cvr this replacement fits older windsor apps and puts the pick-up in the right spot. |
The EDIS-8 unit puts out a PIP signal, which is what most fuel injection systems use to trigger the injectors and simply determines how fast the engine is rotating. It then has a SAW wire (Spark angle width) also know as the spout, this is the signal that tells the EDIS module what to do for timing. This system will run without a computer to support it but like any Ford with the spout pulled it will base the timing back to 10 degrees BTC. It’s conceivable that an after-market control box like MSD could make a programmable box that will interface with the EDIS module and allow a timing curve on a carburated car with no distributor but we haven’t tried it yet.
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| Look Mom! No distributor.This is the Explorer cam position shaft which drivs the oil Pump and is used in eec5 to tell it were #1 is.Usng SpeedPro with bank Fire, the sensor isn't used.It requires mods to work in 351W. |
This is a true crank trigger, as it has no distributor at all, unlike most other aftermarket crank trigger systems which still use a distributor to organize the firing order and have moving parts. The EDIS module also has a tachometer output wire, which may require a tach-adapt depending on what type of tach the vehicle has in it.
This module by itself on a 392 cubic inch motor has pulled to 6500 rpm with 19 psi from a Vortech and not missed a lick. On a 32V modular motor with 25 psi it has pulled to 8200rpm with no trouble but that car also has an MSD DIS-4 ignition enhancer to increase up the spark output in such a harsh environment.
The EDIS modules really shine with the high winding 32V 4.6 Cobra motor. It allows us to transplant these distributorless motors into cars that never came with them and once an after market Fuel injection system is used, these motors will run perfect with proper tuning and assembly.
We are truly blessed that Ford used these modules externally on their early distributorless stuff. Even though these modules have not been used on Fords for 4 or 5 years or so, I feel that it’s a well designed part that will probably run to 9500 rpm and it has truly opened the doors for Modular transplants.
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Please excuse the wires on the engine's left side. We made a mistake on the lengths and had to temporarally rearrange them. |
At the time this was written we have already adopted it to a 351 stroker pushrod motor with Speed-Pro EFI. At this time we’re not going to argue about how much more power it will make over a distributor set-up but the high rpm potential and advantages over a distributor could be a major advantage. For now let’s just say that it’s very cool, cutting edge and unique for push rod motors. We’re confident that at high rpms its many advantages and more accurate spark control will pay dividends.
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The coil packs are used from a 32V Cobra motor and the coil bracket is a custom made peice. We think the Explorer 5.0L coil bracket may look good on a 302 application. |
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This is an under car veiw of the crank trigger wheel and the spacer block we made to extend the pick out to the wheel. |
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