Thursday, 19 December 2002

Fiesta XR2 Turbo Conversion - Wiring guide for MFi

How to Convert | Wiring it up | FAQ | My build diary

By the fact your here you've either stumbled by accident or you would like a further look into the wiring side of things and you have a big mess on the floor and it looks a little like this





Fear not, it's actually quite straight forward and in a couple of hours you'll have a lovely labeled ready to install loom.
First things first look for three main components the two ecu plugs and the purple/blue relay holder this you'll probably find in the dash part of the loom after the fuse box. This is the fuel pump relay, the relay itself is prone to burning out especially if placed within the engine bay.



If you can't find the relay which is bright pink, it is identifiable by the following numbers 69125 followed by 8566 9P704 AA and 6HB30 stamped on the side.
Once you have found these items you will need to pull them out and away from the rest of the loom.
One particular Green/Black wire which originates from the ECU plug will lead you to a relay on the fuse box, it will be Brown and have KE in big letters on the top obviously the wire will need to be cut but also remove the Relay as this will be needed later. The relay is also identified with the following 86AGION323-AB, DIODE SRG PROTECTION, 72UF001 and 9J05 down the side.
Another noticeable set of wires is the 3x Yellow and Black these all meet together and join a large Red/Black and Blue/Black these can be cut at the join.
The rest of the separation process is a case of removing the lights, indicators, temp sender and cooling fan feed (you will use the existing XR2 ancillaries to perform these functions). You will now be left with ignition lives, permanent lives and earths.





Now is a good time to tidy things up start with the two ECU plugs and work your way down just taping every 150mm to keep things in order and also taping around where groups of wires branch off to their sensors.
Okay now that's the hard part out the way. Once the engine and components are in place start putting the plugs on. On the below picture I have labeled all them which should make life a little easier.



The rest as they say is history just get your soldering iron out and make those connections a list of which is below.

  • 3x Browns together (from sensors) - to be connect to earth
  • 1x Black (from ECU) - to be connected to black on coil
  • 1x Black/Green (from ECU) to connect to pin87 on Brown relay
  • 1x Green (from ECU) - to connect to Green lead on coil
  • 2x Brown (from sensors) - to be connected to earth
  • 3x Yellow/Black (feed to sensors) - connect to 10Amp fused ignition live
  • 1x Black (from Amal valve connector) - connect to black lead on coil

  • From the Fuel Pump relay
  • 1x Thick red - This requires a 25Amp feed
  • 1x Brown - connect this to Earth
  • 1x Black - connect to Black on coil
  • 1x Thick Black/Red - This will need to be connected to the live on your fuel pump
  • 1x thin Black/Red - This will be on the same terminal as the above but goes to the Auxiliary air device plug
  • 1x Green/Red - this will be from the middle terminal and again go directly to your ECU

  • Note: Both these wires should have remained connected to the ECU and fuel pump relay holder when the loom was removed, if they were cut then just look at the ecu plug and you should find somewhere along the loom the other end of the two wires(where it was cut)as it will be the same coloured wiring. solder these back together or extend them if you wish to relocate the fuel pump relay else where.

    From the Brown Relay
  • Pin 87 - connects to Black/Green wire describe in above from the loom
  • Pin 86 - requires 10A live ignition feed
  • Pin 85 - connect to earth




Now a word of advice - I wouldn't tape everything up just yet as it's best to check everything works first.
If you don't fancy doing this yourself it's best to find someone who has done this before or they'll probably include their research and development in their costs, I have had quotes from £80 to £900 for the wiring alone so be warned. I ( Andy ) can strip label and post back for £50 if required.


Part 2 Installation of the loom
First off I would suggest getting the loom in position ie connect it all up to the relevant plugs most of the plugs are colour coded to the sensors and those that aren’t will only fit the correct sensor or opposite plug. I have also a table to help on page 2


Once this is done confirm you can see all the wires that need connecting up I have made a check list so you can familiarise yourself with the ends that need connecting and it will be useful to double check if troubleshooting is required. It is pretty much essential you have a multimeter handy as you will need it for check you have the right feed in the right place, it is also useful for checking you have a good earth (another point that can cause teething problems).


Figure 1.1
Label numberWire ColourConnect to
2BrownEarth (from fuel pump relay)
4Black & red (Thick)Fuel Pump Positive terminal
5Red (Thick)Permanent 12volt (put a 25amp fuse inline)
6Black & Yellow x3Ignition live 12v (put a 10amp fuse inline)
10BrownEarth (Various)
11GreenGreen on XR2 coil
12BlackBlack on XR2 coil (from amal valve, ECU & fuel pump relay valve)
13Black and GreenPin 87 on Brown KE relay


After you have connected number 13 to the KE relay you will be left with 2 more pins 85 which will need to be connected to an earth and 86 which will be need to be connected to a ignition live (this can be the same as connection number 6 (shown in Fig.1.1) if it is easier than finding another source) this requires a 10amp fuse inline)

For the fuses simple blade types will be sufficient. I have enclosed a few from the RS Turbo fuse box although new ones are available from your local motor factors. Connect the wires to them using the correct rated spade connector (blue if I remember correctly) the same applies to connecting the wires to the KE relay. I you are not happy with the Purple relay block the Pink fuel pump relay sits in you, can always use the correct rated blade terminals if you wish (Although yours looks in good condition).

Don’t forget you will be using the XR2 loom for the starter motor, alternator(charging system) and other ancillaries such as brake fluid sensors, you should not have to chop into any of your XR2 wiring only to connect up to the coil.

Best advice I can give is just take your time and work through logically any problems let me know and I’ll do my best to help..

Here is a list of the RS Turbo connector plugs. Connecting the plugs shouldn’t be a problem but it’s always useful for trouble shooting.

Connectors table

TypeColourWire colourHaynesref:Destination
Square 2pinBrownBrown/White,Yellow&Black142Thermal time switch
Square 2pinBlueBrown/White, Yellow&Black20Cold start
Square 2pinYellowBrown/Green& Brown141Temp sensor(1)
Square 2pinBlackRed/Black & Brown11Aux Air
Round 2pinBlackBrown/Black & Brown4Air Temp
Square 3pinBlackBrown/Black, Brown/Green & Brown143Throttle sensor
Square 3pinBlackBrown/Yellow, Brown/Green & Brown3Air flow pedeometer
Square 2pinBlackBlack & Brown/Green146Wastegate solenoid (amal valve)
Square 2pinGreyBlack/Yellow & Brown121Pressure Actuator
Square 3pinBlackGreen/Yellow, Brown & Black/Red29Distrubutor
Square 2pinGreenBlue/Yellow & Brown104Knock Sensor
Round 2pinBlackBrown & Brown/Green141Temp Sensor(2)


How to Convert | Wiring it up | FAQ | My build diary

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