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Thread: Write-up>EDIS: When you have no more love for the Dizzy!

  1. #1
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    Write-up>EDIS: When you have no more love for the Dizzy!

    Pasted this from the new 3tc forum. Scared that I might have to re-write it again!

    So here we are with a little write-up on how to take that 2tc or 3tc (or anything for that matter) and rid yourself of the distributor using Ford’s EDIS-4 system. EDIS-4 is a nice crank triggered ignition system that is capable of a good 40,000volts max discharge, 57 degrees of total advance and an upper limit rpm of around 9500rpm.

    Some of the things you will need to scavenge:

    1 EDIS-4 ignition module with connector available on some 90-93 Ford Escorts.

    1 controller to supply the SAW command for advancing the timing. I used Megajolt by autosport labs but other controllers are available.

    1 36-1 trigger wheel. That’s 36 teeth minus one tooth.

    1 Ford style 4 tower coil pack or two two-wire dual output coil-packs.

    18 feet of two conductor shielded wire, 18 gauge. Has a groundable foil shield around the two wires inside.

    1 Variable Reluctance Crankshaft Sensor

    1 Laptop with your choice of connector to set your map.

    Various wire 18 gauge, and also 16 gauge wire for grounds plus any connectors you choose to use.

    I also chose to use the Autosport labs rev limit module for a spark cut rev limit on my carbed car.





    Lots of reference and wiring info here: http://www.autosportlabs.net/MJLJ_V4...allation_guide

    You must decide whether your system will use a throttle position sensor (TPS) or manifold absolute pressure sensor (MAP). I used a map sensor but given my camshaft right now, I wish I had used tps. The vacuum is just too uneven a idle.

    So The first thing I did after gathering parts was to set about figuring how to mount my 36-1 trigger wheel. I got my trigger off a Ford Focus SPI engine by heating the trigger wheel until it was red hot and then just lifting it away with pliers.

    I then machined a 1976 corolla crank pulley from a 2tc equipped with AIR (air injection reaction system) to an interference fit. This allowed me to install the trigger wheel onto the pulley the same way it was on the Ford pulley-with no welds needed.





    The placement of the trigger wheel missing tooth relative to the VR sensor is the critical factor. The VR sensor must be 90 degrees BEFORE the missing tooth when the #1 cylinder is at TDC compression. It basically has you line the sensor with the 9th tooth back. This allows you some room for you to tailor the install to your project because they just have to maintain this relationship.

    For mine, I did not want any RF or magnetic interference for the sensor so I fabbed up a simple right angle bracket that would bolt into the two AIR pump holes on the right side of any T block. A simple pizza box helped with figuring the original measurements.









    One thing to consider is to make elongated holes to allow for fine tuning of the sensor gap which should be about 1mm and the sensor alignment with the trigger.

    Note also that I have a gusset that you can see on one side but also a gusset on the inside of the bracket. This is try and stop any movement or vibration at high rpm which can create an erratic sensor input causing a misfire. Bad news!

    I also used the foil shielded wire for the VR sensor and the PIP/SAW wiring. Now the VR sensor is a simple ac voltage generator. The wires are polarized, one positive and one negative. Hooked up one way the system will work, the other will result in no spark. I suggest leaving this connection loose until you know which way will work. On my sensor the wire closest to TDC was negative.

    The next step for me was to mount the coil.



    After some playing around I decided I did not like the look of the Ford coil so I got two coil packs from an early 90’s Toyota Paseo. (toyota part # 90919-02213
    ) They hook up the same way as the ford one as the ford one is just two coils as well. One common power Vref + and separate trigger signals for each coil 1 and 2 from the EDIS module.



    In my picture of the engine bay, the wire closest to the front of the car on each coil is + and the ones towards the firewall are – which go to the edis module coil outs. I used Toyota weatherprooofed connectors #90980-11246 quantity of 2 and wire splices #82998-12440 quantity of 4.



    Next you must remember that you still need to drive the oil pump which is accomplished by the distributor on a T motor. 4ag and some other motors don’t need to worry about this so they can just seal the dizzy hole with a frost plug. To drive my oil pump I cut down a distributor and filed it nicely leaving the threaded holes from the cap. I cut out a piece of steel to screw on as a cap for the new “Dum-dizzy” and installed it. One season later I have had no problems.



    Looks like it needs a sticker!


    Once I had the oil pump figured I had to try and steady the vacuum signal from my individual runners. I have sidedrafts so I needed a signal from all four cylinders. No worries, I tapped a port into each runner using threaded vacuum fittings.

    I hooked rubber hose to the fittings that joins to hard plactis hose from Vibrant. Vibrant makes a nifty alloy block that brings all these hard plastic hoses to a junction and makes a clean install.

    http://vibrantperformance.com/catalo...Path=1020_1028

    The fittings are little pneumatic compression fittings so they are turbo ready! I had to ensure that the hose going to the map sensor had allow enough spot to reduce the likelyhood of oil fouling the sensor.

    Once I had that all figured out I went to work mounting and wiring the EDIS module. The trick here is to be patient, use double wall heat shrink tube (the stuff that oozes glue out the side after shrunk), and hook it up so that it will run without any controller the first time. This allows you to be sure that the basic wiring and module are working correctly before adding the controller as a variable.

    Speaking of wiring, I use two 7.5A ato fuses-one for the edis module and one for the controller. That way if the controller craps out, you can still limp home with a fixed timing of 10? BTDC.

    When you get the whole thing running, you can use a timing light to check the static edis timing of 10? btdc. If it is off by a few degrees don’t panic. You can remember the variance and adjust your map accordingly. Side note** EDIS will do timing below 10? all the way down to 0?. The controller can be set to go that low if you need so don’t worry 10 is not the minimum.

    It is also neat to see how accurate your stock tach IS NOT! On the subject of tachs, most old cars have tachs that utilize the flyback pulse that results when the coil's magnetic field collapses. This pulse is captured off the negative side of the coil. Modern cars use the pip signal generally for the tach. If you have an older tach you will need to harness the flyback pulse from BOTH coils or sides of your coil pack to get a useable signal. The trouble here is that if you simply connect the two negatives together via a junction then they will both fire at once-NO GOOD!

    You must get two 1N4004 diodes and one 15-18v zener diode. You will need to learn how to identify the bias (google it) so that the flyback pulse can leave the coils but not fire each other. One 1N4004 diode for each negative side of you coils. Then you connect them at a junction or splice and from there they both pass through the zener diode (check the bias!) and to your tach input. then you should have a nice happy signal.



    Then its time to start for creating a map. This is the look-up table that your controller will use to decide timing. You load a basic config to start your car from here:

    http://www.autosportlabs.org/viewtopic.php?t=1113


    And the base screen you will find is on the MJLJ configurator like this.



    So much stuff to play with. You will likely want to edit the ranges on your load bins. ie: most of us don't rev to 10,000rpm.

    ADD-ON OPTION PART- The next thing I did was to wire up the rev limit module.

    I wired the module inside the case of the megajolt unit but some of the wiring is external. If you decide to use the rev limit module you will want to plan ahead as both coil Vref+ feeds must go through the rev limit unit. The module is simple in design in that is a series of resistors that ramps the coil current at a preset rpm. And it works very well! It has a soft limit that runs cushions the hard limit.









    Now the only thing I have yet to do is put my scope on the car running at high rpm and see how much reserve voltage I have left. This will tell me how much I can open up the plug gaps.


    Hope this write-up helps!
    Last edited by sunray; 02-20-2009 at 12:05 AM.


    Or you could have said "sorry, my kidnap victims keep kicking my elbow, it made me drop my crack pipe and swerve"

    -bangnscrape

  2. #2
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    Quote Originally Posted by sunray View Post
    Neat! Looks exactly like how I set my sensor up on my 4k-c engine.

    One thing about the dizzy I did differently is I cut it off right down to the mount (where it bolts onto the block). Then TIG welded it shut, ground it smooth and painted it. There was nothing left of the dizzy except for a 3/8" thick piece bolted to the block.
    ACE Engineering
    1990 Toyota Celica Alltrac (Daily driver)
    1982 Toyota Starlet (Turbocharged race car)

  3. #3
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    Rumor has it edis signal breaks up at high RPM???

    Any word on this. I might go another route.


    RETIRED

  4. #4
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    As for break-up at high rpm, you can usually view that phenomenon with a scope tied into the vr sensor. You will get an erratic sognal at high rpm.....due to a poorly constructed bracket moving or vibrating. Note the gussets on my bracket, one outside you can see and one inside you can't see. I'll add this info too.
    Last edited by narfy; 02-20-2009 at 09:10 AM.


    Or you could have said "sorry, my kidnap victims keep kicking my elbow, it made me drop my crack pipe and swerve"

    -bangnscrape

  5. #5
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    Quote Originally Posted by JungleMatic View Post
    Rumor has it edis signal breaks up at high RPM???

    Any word on this. I might go another route.
    I found two capacitors specified incorrectly on the BOM which causes the MS to drop out the RPM signal, after a lot of searching and scoping C31 and C32 I believe were to blame. Replaced them with smaller value caps and the rpm signal was fine after that.
    ACE Engineering
    1990 Toyota Celica Alltrac (Daily driver)
    1982 Toyota Starlet (Turbocharged race car)

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