Hard Start Relay

Discussion in 'Mech Tech' started by Paul Jones, Feb 12, 2019.

  1. Hi Guys

    I'm fitting hard start to my van I bought the kit blue to earth yellow to battery redto spade terminal on starter and yellow to battery and brown to Starter solenoid.
    Now on my starter solinoied iv a thin black wire a thick black wire and two red wire.
    Where do I put the brown wire?

  2. Right, its hard to work out what you have.

    Tell us the correspondence of the wire colours to the numbers of the relay contacts..

    And "dont cut the blue wire!!" ;)

    The job of the relay switching contact is to join battery positive to the starter motor solenoid ignition switch male spade tag.

    You pull the female spade connector off the starter motor. Thats the wire from the ignition switch.

    So the coil of the relay goes between earth and the female connector coming from the ignition switch.

    So the relay clicks when the ignition switch is turned to start.

    The switching contacts of the relay then create a path between battery positive (big wires from engine bay on one big connector post) and the male tag on the back of the starter .. this pulls in the solenoid that then connects the battery to the starter motor.

    A bit later on you will realise that actually it was the ignition switch that was burnt out anyway and the starter motor was sick..
    But the relay will save your new switch from burning... and later on you will how much scene tax you were charged for an ornery 32 amp automotive relay.
    By the way mount it somewhere dry or at least with the relay connections pointing down as a relay full of water is less reliable than a worn out starter motor.. like it stops working...
    Last edited: Feb 12, 2019
  3. I've a start relay fitted. It powers the starter solenoid directly from the battery, and is energised from the ignition switch.

    As a bonus, I can start the engine by shorting the two larger terminals with the same 30mm ring spanner used for turning the engine manually.
    The ignition on/off is provided by hotwiring from the battery straight to the coil.

    This makes tuning the ignition much easier than running back and forth to the cab :thumbsup:

  4. Its a good idea fitting one to take the load off the ign switch. I mounted mine to the bulkhead behind the engine on the offside. Don’t forget the fuel tank is behind it when you drill a mounting hole :rolleyes:
    Used a Standard mini relay base with a 30A relay. As mentioned its handy if you want to crank the starter at the back of the van, simple bridging lead.
  5. ^^^^^ Tidy loom that snotty :thumbsup:
  6. I got one of the empi kits and one of the wires that were with kit was a different colours to the instructions .
    I replaced it with one that was the same as the instructions then it was easy to fit .I can't remember which I changed though
  7. You'll be better off looking at the relay contact numbers, which should be marked on the relay base, rather than wiring colours which are going to vary. Disconnect battery -ve, pull spade connector off of starter solenoid. Connect relay suchly...

    30 - supply from main +12V terminal stud on back of starter
    86 - original lead from ignition switch
    87 - to (now-vacant) starter solenoid spade terminal
    85 - ground (under relay mounting screw is fine)
    theBusmonkey likes this.
  8. Bit of a loom-ette, so I could stick it in the engine compartment.
  9. I'd quite like to make a remote starter lead that I can just plug in when needed. What do you use for the push button?
  10. Really anything will do - it's only handling the relay coil current (maybe 100mA?). The button just shorts terminals 30 and 86, to energise the relay from Down The Back, without having to use the starter switch up front.

    I just used a chunky pushbutton stuffed into a length of plastic tube. The connector's just a 2-way automotive job. Very handy for compression testing :thumbsup:
    andyv and Dubs like this.

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