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325e m20b25 swap NO POWER TO PIN 27! Help

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    325e m20b25 swap NO POWER TO PIN 27! Help

    I just finished swapping an m20b25 from a 1987 325is into my 325e. I adapted the early model rectangle fuse box plug to the round c101.
    The car cranks and turns over but will not fire up.
    Pin #27 (start input-to ignition switch and coil) does not show any voltage with ignition on???
    No Spark
    No fuel
    I would really aprecciate some help here. Thanks!

    I followed this list of steps and the only thing that was out of place was no voltage at Pin #27 when ignition is turned on.

    For the engine to run the following conditions must be met:

    Power on DME pins:
    27 Start Input
    18 Un-switched Power input
    37 Power Input from Main Relay

    Ground on DME pins 2, 14, 19, 24

    Timing data from the CPS on DME pins 47 & 48 from a rotating engine

    To have spark power must be present at the coil positive and ground pulses
    from the DME's pin 1 must reach the coil negative. Power to the coil is
    controlled by the ignition switch via C101. When checking for spark, use the
    output lead from the coil to eliminate the distributor, rotor and plug wires.

    To have injector firing power must be present at each injector and ground
    pulses from the DME's pin 16 (Bank1) and pin 17 (Bank2) must reach the
    respective injector bank. Note that the injectors are wired as two banks of
    three. With cylinder 1,3,5 being bank 1 and 2,4,6 being bank 2. Power to the
    injectors is controlled by the main relay. Injector firing is best checked
    with a noid light.

    The fuel pump relay must have power on pin 86 (relay coil) from the main relay
    output (pin 87) and power on pin 30. The DME will ground pin 85 to turn on the
    relay and power the pump(s) via pin 87. Of the above, only the fuel pump power
    is fused. So if the there's power at pin 87, but not at the pump, check fuse

    The main relay and DME pin 18 receive power from the smaller of the to wires
    that connect to the battery's positive terminal. That wire incorporates an
    in-line fuse. When the DME is presented with a start signal, it grounds the
    main relay pin 85 and furnishes power to the fuel pump relay, injectors, and


    Disconnect the battery and the DME cable. Then:

    1) Disconnect the coil negative and check continuity from that connector to
    DME pin 1. Also verify that from DME pin 1 to ground is an open circuit.

    2) Check the resistance across DME 47 & 48, which should be 500-560 ohms. If
    the CPS is dismounted, the resistance can be seen to change from about 500 to
    540-560 ohms when a ferrous object is brought to the face of the
    sensor. Neither pin should be grounded.

    3) Check for continuity from DME 36 to main relay 85 and from DME 3 to fuel
    pump relay 85.

    Reconnect the coil, remount the CPS (air gap should be 1mm), plug the
    relays back in, reconnect the DME, and connect the battery. Then do the
    following checks:

    1) With the key off, verify that power is present at DME pin 18 and main relay
    86 & 30.

    2) With the key on, verify that power is present at DME pin 27 and pin
    18. Power to pin 18 is from the main relay and there should be power to the
    injectors and fuel pump relay.

    3) With the key on, verify that no voltage is present at the DME grounds (2,
    14, 19, 24).

    4) Verify that power is present at the coil positive and at fuel pump relay
    pin 30. Those get switched power from the ignition switch via C101.

    The engine will start and run (if poorly) with only those connections to the
    DME in place. The other signals from Cylinder ID, AFM, temp sensor, etc., are
    necessary for proper operation. But they won't prevent the engine from firing.


    A power check means seeing a voltage within about a tenth of a volt of what
    you measure across the battery terminals, which should be at least 12.6v on a
    charged battery.

    A continuity check means seeing less that 1 ohm of resistance.

    An open circuit means seeing a resistance of at least 100k ohms.

    A good quality auto-ranging digital multimeter will make these tests much