Adding Fuel Injection to an X1/9

Discussion in 'Workshop Forum' started by bbrown, Aug 5, 2014.

  1. bbrown

    bbrown Bob Brown Moderator

    New Hampshire
    -A wiring instruction on how you add fuel injection control to what would formerly be a carb'd X19.

    This section covers the interface to the Fuel Injection harness only. This would be your
    starting point. If you have all the hardware from a Fuel-Injected X that you want to
    put into your carburated X1/9, this is what you'll need to do it.

    To complete this section, you will need:
    1. Fuel injection "dual relay" plug. (Midwest Bayless?) It would be nice to get the
    plug with wire lengths already attached for ease of connection.
    2. Assorted wire lengths of:
    10 Ft. 12Ga Red
    10 Ft. 14Ga Brown w/white stripe
    6 Ft. 14Ga Green w/black stripe
    10 Ft. 14Ga Pink w/black stripe
    10 Ft. 16ga Red w/black stripe
    3. Electric Fuel Pump. (The Bosch pump is recommended)
    4. Two ATO fuses with in-line holders (sockets) 7.5Amp and 10 Amp

    Use solder (recommended) or crimp connections as desired.

    To finish the job, you'll need to obtain the rest of the Fuel Injection hardware.
    This section covers the interface to the Fuel Injection harness only.

    Refer to the photo referencing placement of the wires into the connector and their destination points.
    It is OK to add these wires to your existing setup and fuse accordingly using separate ATO-style fuses.

    The dual relay and Bosch ECM takes care of fuel pump management.
    No need for anything special attached to your oil pressure switch or other to make the fuel pump work.

    The Fuel Injection Harness (not shown!) plugs into the left of the relay and draws it's power through the dual relay.

    This modification handles ALL control to the fuel pump, injectors, MAF sensor and other sensors
    once connected to the FI harness. Basically, it's all about this single white plug shown below.

    Wiring instruction:

    Details are not covered here, but you'll need the rest of FI pieces and mechanical parts to complete
    the system. Part of that list includes:

    Fuel lines installed that accommodate the FI system
    Fuel Injection Harness
    Bosch ECM
    Air-Fuel Meter module
    An Injector rail and associated FI hardware (plenum, air intake hoses, etc)
    Four Injectors
    Cold Start Injector
    Throttle position sensor
    Knock Sensor
    Crankcase Fume emissions Valve (the name escapes me)

    Hope this is of use to those who want to convert their old system to Fuel Injection. -Bob
    Last edited by a moderator: Jul 29, 2018
  2. JimD

    JimD Waiting for Godot... Moderator

    Missouri, USA
    Thanks Bob

    This will give me a lot of confidence when I get to the point where i am ready to wire the FI into the 78. I have all the mounts installed for the various FI gizmos that don't exit in the carb's car, but I need to wrap up some mechanical issues before I get to the electrical.

    Where do I go to get wires in the colors and sizes?
  3. bbrown

    bbrown Bob Brown Moderator

    New Hampshire
    Matt or me

    But if you get them from me, you might have to wait a while.
  4. JimD

    JimD Waiting for Godot... Moderator

    Missouri, USA
    Good to know


    I am not in a hurry, so let me know if you hove lots of "extra" wire and want to recoup some cost. If you want to hang on to the wire for the future, I will talk to Matt.

    Thanks again for all you do for us electrical dumazzes. :)
  5. lookforjoe

    lookforjoe True Classic

    Nice work!

    Handy reference for me, as I am cutting all the stock FI out of my X1/9 :) - I was getting ready to look through the factory wiring manual to determine which of those wires I need to retain to feed the LH2.2, your reference pic makes it simple, thank you!
  6. budgetzagato

    budgetzagato Administrator Moderator

    Olympia, WA USA

    When I converted my Scorpion to L-Jet using mostly Beta stuff, I found that having a hard-start relay installed in the engine bay made for a great place to piggy-back the power and cranking wires. Plus the fused power for the hard-start relay means the power to my dual relay is fused.

    The L-Jet (at least as used on Fiats and Lancias) doesn't have a knock sensor. Additional parts needed include the Thermo-Time Switch and the Temp Sensor II, which is mounted in the F.I. models' thermostat housing.
  7. mikemo90

    mikemo90 True Classic

    f.i. in a carbbed car

    if you have access to the original f.i. harness it is only a five wire to the existing harness in the car. I have it in my 74 now and surprised how simple it was. I will try to retrace my steps, and test the bunch of f.i. stuff before I put the duals back on. I will have what I want sell on the fs&w very soon. have to make room for a new x!!
  8. bbrown

    bbrown Bob Brown Moderator

    New Hampshire
    That's right Mike,

    Just as the photo shows. 5 wires, 4 of which go to the fuse box area. One of these can (likely) be wired
    directly to the starter motor's 4Ga lug that's fed directly from the battery but I'm unsure this would be
    wise. (due to the heavy current draw when starting) If it were me, I'd run the 3 lines up front and not take
    the chance. One of these wires (the 16Ga Red w/blk stripe) can go directly to the starter solenoid line,
    but I think I'd run that one up front too.

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