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Fuels Ignition
EDIS |
| CONTACT
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| Unless otherwise indicated all material is copyrighted: KEW Engineering Ltd 2011 |
To get the best performance from the system you must route the cables in such a way as they do not run close to the spark plugs and other HT leads. With exception of the VR sensor this is quite possible. If you decide to purchase Matthew's loom the lengths are already pre-cut and terminated and as such you should find they go in with some slack should you wish to make minor adjustments. If you want to do a radical re-route you may need to replace the cables with longer lengths. This would require cutting and re-terminating. Please only attempt this if you are totally confident in your soldering and wiring diagram skills. It is not difficult but there is scope for error which can then be hard to fault find. See the wiring diagram for more info at the base of this manual.
There are three cables
that run from connectors on the box itself.
Assuming you put the box in the glovebox or thereabouts, the following routes
assume this is the start.
Cable 1. 6 way (one pin spare) Coil pack +/-, 12v, ground, Tacho
Cable 2. 2 way VR sensor +/-
Cable 3. 3 way Throttle position sensor
Cable
1 comprises several functions and as such you can split it fairly
early on or tape it up to keep it neat. The thick back cable must be run up
along the back of the dash behind the centre console and above the steering
column. Then route it through the large main loom hole situated next to the
windscreen wiper motor and leave it poking out next to the brake pedal box
within the engine bay. We’ll connect it up later.
The single black wire needs to go to chassis earth and you can do this fairly
close to the box. Just drill a 3mm hole in a solid part of the dash mount and
use a self taper and shake proof washer to hold the circular connector in place.
The red wire must be connected to switched 12V. If you connect it to
permanent 12v the car will start but you wont be able to stop it!
Matthew suggests routing it along with the coil pack wire and then branch off,
connecting it up to a spare terminal on the ignition switch. Alternatively route
it all the way round to the fuse box. The tacho wire should connect directly to
the tacho. On early tachos this is a bit more fiddly and Matthew needs some
feedback to get this right.
Cable 2 connects to the VR sensor and takes the longest route of all the cables. It can either go on the exhaust side or along the engine on the spark plug side as shown below. To keep it tidy route it along with Cable 1 but then branch off and join the oil pressure pipe exiting into the engine bay. The cable then runs along the engine under the plugs as shown below. (Thick black cable). Matthew has bolted a cable anchor point to the lower bolt on the alternator bracket. This just stops it flopping about. From here it then runs around the alternator and connects up to the sensor itself. Matthew has had no issues with the cable here and to be honest the exhaust side of the engine is hotter and therefore more likely to affect the cable insulation.
Cable 3 takes the simplest route by coming straight out of the back of the box, through the bulkhead and across to the carb. You will need to mount your Potentiometer on the carb spindle and this has been achieved on both a Weber and SU carb with little problem. See below for more details. Depending on which side you mount the pot will determine the way it rotates with increasing throttle. This is not an issue as the direction can effectively be reversed in the software package with a few clicks of the mouse.
Below shows the connection to the sensor. Focus is poor but you can see the general detail. The cable comes in from underneath the alternator. The actual sensor is attached to the alternator mounting via a length of aluminium or steel bar. The bracket is shaped accordingly to present the VR module at the toothed ring. The first two shots show a 65 B and with Bs from 1976 onwards there is far greater space in which to work (see Fitting EDIS to a later rubber bumper B/BGT). Max allowable distance away from the trigger wheel is probably around 3mm, although it would be better to aim for as close as possible within the tolerance of any run-out on the trigger wheel.
The coil pack requires 12V power and to be a reasonably short distance from the plugs. As a result locating it near the fuse box or brake pedal box will be fine. There are 4 holes located in the four corners of the pack. You can use long bolts and nuts to space it off the mounting area. It does not need to be insulated from earth.
The pack has 3 pins. Two outer ones receive the firing pulses and the central
one connects to 12V. This pin can be permanently connected to the 12V supply as
it draws a miniscule amount of current when the car is switched off. The
permanent 12v is also a cleaner source and will provide unlimited current.
You will see the connector has a black lead which travels back to the box and a
red lead. Connect the red lead with a suitable connector to a spare tab on the
fuse block that is permanent 12V. Usually brown wires represent 12V permanent.
The picture below shows the coil pack with the connections labelled.
Note the coil pack is labelled on the actual moulding. 2 and 3 are purposefully swapped over to go to cylinders 3 and 2 respectively.
Optimum location for the coil pack is shown below, although again with differences between the engine bays of pre and post 1976 cars, the coil pack can be mounted on the left-hand side of the heater box. See also location as depicted in Fitting EDIS to a later rubber bumper B/BGT.
Fitting the TPS (Throttle Position Sensor)
The throttle position sensor is an integral part of the system and although being simply a variable resistor, it must be positioned in such a way as it will rotate with the throttle spindle without slipping. See the photos below for a simple but effective way of doing this. The actual potentiometer can be protected with a small 35mm film canister. It doesn’t need any mechanical calibration other than the pot must turn with the throttle spindle from fully closed to fully open. The calibration is done later in the software package. The picture below shows our trial set-up on a 79 BGT. The throttle spindle is connected to the end of the pot via a short length of rubber tubing. Looks crude I know but it works. There is room for improvement here so experiment away!
Although untried as yet, it is likely feasible to source a TPS off an inlet plenum on a modern car.
Throttle Position Sensor shown below on a twin SU set-up on the rear carb throttle spindle.
Copyright Matthew Kimmins 2006-2009