Ford EEC-IV wiring (1993 Mondeo, Zetec 2.0)

[alga]

So, I have got the engine wired and running with the stock ECU. Some notes:

* I'm using an LED with a resistor to read error codes on the STAR connector. I made a plug to connect to the triangular STAR socket by pulling out the terminals out of a similar plug and inserting them into a triangular male plug which was used to blank one of the unused plugs on the engine harness, speed sensor or somethinlg like that.

All the removed systems (Pulse Air, EGR, Power Steering valve) are ringing error codes in the STAR connector. They are a bit annoying as you have to read them all slowly just to see if there are any other codes. I'm not sure if it's worth silencing these errors by adding resistors where needed. Fuel pump relay code is also signalled. Probably the ECU expects the pump to stop after building out the pressure when the engine is not running, mine is always running when ignition is on.

* The tach signal is 12V positive pulses 1 ms in duration. Sierra's tach expected a coil signal, with negative pulses from 12V to 0, and didn't work with the ECU signal. I made a logic inverter out of a MOSFET, now the tach works. I can post the schematics if anyone is interested.

* The radiator fan control signal is grounded for off, disconnected from ground for on. So, another MOSFET is needed to drive the fan relay, or a normally closed relay. Or an original transistor fan relay out of a Mondeo.

* The engine tends to foul plugs, from time to time one of the cylinders refuses to fire due to no spark. Might be old sparkplugs, or the engine might be running rich at idle. I think the ECU relies on EGR at idle speeds. I haven't gotten around to checking the oxygen sensor yet.