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Thread: Advise required - 12v feed to injectors query

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    Advise required - 12v feed to injectors query

    Hey all,
    Hoping to draw on the wealth of knowledge from everyone here as I’m rather new to s-bodies!
    So the current situation is I have recently put a SR20 DET engine from a 1994 S14 into my 1997 S14A.

    The setup in the car is:
    S14 parts - Engine & engine loom
    S14A parts - Main loom & ECU

    The reason I have done this is because I had a full S14A except:
    -engine
    - engine loom
    - main loom (one that goes through the bulkhead)
    - ECU

    But my best friend sourced a fully running donor car in the form of an older S14.
    The engine in the donor car ran perfect before removal so we know the engine is good however the current problem now post-transplant is that the car cranks over but does not start.

    I have checked:
    - fuel supply - is fine into rail (also right way around)
    - spark - getting spark
    - engine cranks over

    On checking the injectors they’re not spraying, upon checking the voltage, they don’t look to be getting 12v.

    My query:
    Is anyone able to advise the route the 12v takes to get to the injectors & what (& where) to check for potential problems..

    Cheers for any help offered guys & girls!

    All the best,
    CJ

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    I <3 BBS LM Actual_Ben_Taylor's Avatar
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    First place to check would be the crank angle sensor

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    Advise required - 12v feed to injectors query

    Sounds like a nats issue, also have you swapped the pins on the ecu (think 3 need to be swapped over from memory when running s14 engine with S14a ecu)


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    Quote Originally Posted by Actual_Ben_Taylor View Post
    First place to check would be the crank angle sensor
    Cheers for the reply,
    What would I be checking it for.. the engine ran perfectly the day before, what would of changed?

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    Quote Originally Posted by cj. View Post
    Cheers for the reply,
    What would I be checking it for.. the engine ran perfectly the day before, what would of changed?
    Does the rev counter go mental when you crank it?

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    Quote Originally Posted by kingk View Post
    Sounds like a nats issue, also have you swapped the pins on the ecu (think 3 need to be swapped over from memory when running s14 engine with S14a ecu)


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    Hey KingK, thanks for the reply buddy;
    The Ecu has NATS disabled,

    Would be very keen to hear more about the pins that need to be swapped over as this hasn’t been done.
    Don’t suppose you are able to shed any light on these 3 or have a link to where this is detailed at all do you matey?

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    Advise required - 12v feed to injectors query

    Ok well that rules that one out.

    I think you need to connect the CAS signals together and add an ignition live to the ecu as they’re different. I’ve found threads on the forum before with the info you need, so you should be able to find something if nobody knows off the top of their head


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    Advise required - 12v feed to injectors query

    Quote Originally Posted by Actual_Ben_Taylor View Post
    Does the rev counter go mental when you crank it?
    Yes Ben, it does

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    Quote Originally Posted by cj. View Post
    Yes Ben, it does
    CAS wires need switching.

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    Quote Originally Posted by Actual_Ben_Taylor View Post
    CAS wires need switching.
    Ah ok,
    - Don’t suppose I could trouble you for details on what exactly needs switching & where could I dude?

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    Also, what has the CAS wires got to do with the 12v feed to the injectors? From how I understand it, the 12v is provided from when the Ignition is in the ‘ON’ position (ie before the car is even running) ?

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    I <3 BBS LM Actual_Ben_Taylor's Avatar
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    Quote Originally Posted by cj. View Post
    Ah ok,
    - Don’t suppose I could trouble you for details on what exactly needs switching & where could I dude?
    The following pins on the ECU

    22 -> 31
    30 -> 40
    31 -> 22
    40 -> 30

    Or swap them at the plug on the CAS

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    Quote Originally Posted by Actual_Ben_Taylor View Post
    The following pins on the ECU

    22 -> 31
    30 -> 40
    31 -> 22
    40 -> 30

    Or swap them at the plug on the CAS
    Superstar, cheers Ben,
    Will give that a go..

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    Quote Originally Posted by Actual_Ben_Taylor View Post
    The following pins on the ECU

    22 -> 31
    30 -> 40
    31 -> 22
    40 -> 30

    Or swap them at the plug on the CAS

    Quick secondary question off of the back of this if I could dude,

    As well as switching these CAS wires over,
    Is there another wire that needs addressing to provide the constant 12v to the injectors?

    - I only ask as currently when measured, there is 0v being received by them..

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    Quote Originally Posted by cj. View Post
    Quick secondary question off of the back of this if I could dude,

    As well as switching these CAS wires over,
    Is there another wire that needs addressing to provide the constant 12v to the injectors?

    - I only ask as currently when measured, there is 0v being received by them..
    The power comes via the F4 plug and as far as I can tell from the wiring diagrams it uses the same pin for S14/S14A (pin 40)

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    Quote Originally Posted by Actual_Ben_Taylor View Post
    The power comes via the F4 plug and as far as I can tell from the wiring diagrams it uses the same pin for S14/S14A (pin 40)
    Cheers buddy,
    Being a complete sbody n00b,
    Which plug is the F4 plug?

    (Really appreciate your help with this dude )

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    Quote Originally Posted by cj. View Post
    Cheers buddy,
    Being a complete sbody n00b,
    Which plug is the F4 plug?

    (Really appreciate your help with this dude )
    Update:
    Ah think might have found the answer to that query.

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