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GTM Coupé Page 13

September 2007

Well almost a year up, and not as much progress as I had hoped.

Must spend more time on the car, and try to get it "MOTed" before winter sets in.

this month started by spending more money via Ebay, where I picked up a MegaJolt board.

MegaJolt Board
MegaJolt Board

This will allow me to remove the distributor and replace it with a 3D mapped ignition system.

A successful trip to the scrap yard today, yielded nearly all the parts I need to hook up the Megajolt.
A nice light blue Escort, gave up its EDIS module,coil pack, spark plug leads, and variable reluctance sensor all for a grand total of £10.00.

Ignition parts
Ford Ignition Parts
Ignition leads
Escort sparkplug leads

Just need to find a trigger wheel to fit now.

Updated the MegaJolt board I have with the latest firmware, and also added an option to allow two switchable maps to be used. The modification allows one of the unused multipin connector to be used as a remote switch, as the control box will be easily accessible where I intend to fit it, I change it slightly to allow fitment of a switch to the case. I also intend to fit a bi-colour LED to the case as a power/map light. I also took the chance to cable-tie down the map sensor to the board.

Modified Megajolt
Modified MegaJolt board

Using a box bought from Maplin, I made a case to fit the board, I had problems finding a bulkhead fitting for the vacuum pipe, so I cut a thread on a windscreen washer pipe joiner. I also printed out a label to allow me to note the configuration of the unit. This will need laminating later to give it some degree of protection.

Cased Megajolt
Megajolt board in case

In my planned installation I can reach the ECU, so I fitted the box with a switch and bi-colour LED to indicate the map in use.

Map 1
Map 1
Map 2

As I plan to run a MAP (Manifold Absolute Pressure) system for the ignition, it means I need to measure the vacuum at the inlet, as I'm running a weber it means that each side of the inlet, needed tapped and connected. As the cam in the car is a little bit "lumpy" I have used a t-piece with a little brass restrictor in place. I'll let you know if this evens out any pulsing. Hopefully I'll get the megajolt temporary hooked up to monitor the pressure some day soon.

Vacuum take off
Vacuum take off
Brass restrictor
Inlet re-fitted
inlet with vacuum tube

It seems that my idea still doesn't smooth the vacuum out enough, so I will have to fit a small vessel of some sort get a smooth enough signal. Several people have used a small disposable fuel filter, and as I need to get one anyway, I might as well get two.

trace log
trace log of vacuum

Spent a little time today, fitting the fuel tank, fuel pump, radiator fan and horn back into the car. Some temporary wiring and it all works!

Tank back in
Tank, radiator, horn, and fuel pump back

Was nice to let the car run for more than a few minutes, everything seems fine and the fan switches on and off like it should. Placed a small fuel filter into the vacuum line from the manifold, this seems to smooth the signal slightly, but there is still a little "ripple" on the signal. Not sure if this is because the engine is not tuned, and running a little rough it's self. I plan on fitting a slightly large filter to see if that helps, may also change the t-piece for one that has no restrictor first to see what difference that makes.