Ellectronic fuel pump

Discussion in 'Mech Tech' started by Peakynut, Apr 13, 2014.

  1. A simple single-pole relay will do. You don’t need one with a built-in “kickback” diode (some have a resistor). They’re used if you’re driving relay from a transistor or summut electronic, to prevent the reverse voltage from the relay coil damaging electronic kit. Doesn’t matter if you have one - just connect relay coil the right way round.
     
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  2. Chrisd

    Chrisd Supporter

    :) new relay works a treat, 4 pin Halfords. It even primes the carbs on ignition, pre cranking. The added bonus is that the engine starts first time as less drain on coil as I was hoping.

    Thank you all for your help.
     
    PanZer likes this.
  3. Excellent. The triggered relays are of debatable value. Worth putting your cutoff valve in, so you can shut the fuel off if you have a blaze in the engine compartment.
     
  4. Chrisd

    Chrisd Supporter

    That is the next thing.

    I think the relay I have just put in will take the shutoff solenoid as well i.e. #87 feeding both the pump and the shut off valve. But that means that whilst the key is in the ignition stage, then the cut off and pump would continue to work.

    So is there a better way to power the shut of solenoid? I've seen posts about feeding from the alternator, again via another relay I think. I must look this up further.
     
  5. Mine’s just connected to the coil 15 via a fuse.
     
  6. Chrisd

    Chrisd Supporter

    Is there any reason why I couldn't take it via my new relay?
     
  7. Nope.
     
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  8. My shut off is just piggy backed with the pump.. no pumping, valve shuts..

    Sent from my SM-G960F using Tapatalk
     
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  9. mikedjames

    mikedjames Supporter

    This is a single low-cost relay solution. There should really also be a 1 amp fuse on the alternator warning light blue wire (D+) as if you short that one to ground, you kill the alternator pretty effectively (although your bag of 1N4001 diodes you bought off eBay will provide the three diodes you need to fix it !!)

    Relay.jpg


    The only thing you need to check here is that with the ignition on, the engine stopped, and the alternator warning light on on the dash, that the relay is not too sensitive, and it does not stay closed with the current provided through the warning light .

    The ignition pulse type relay is better in that it needs definite pulses from the ignition - these will start as soon as the engine is turning and the ignition coil is powered, so the pump will run to prime during the early part of cranking if you need it, and even when the ignition power is first fed to the relay it clicks on so it closes for maybe 20 seconds when you turn the key to run without ignition pulses, and then is retriggered by the ignition pulses.


    I think I will sketch out the kind of circuit inside the ignition triggered relays next..
     
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  10. Chrisd

    Chrisd Supporter

  11. Hi. I have been looking this tread as have decided to fit an electric fuel pump and have opted for a Facet 60300 Electric Fuel Pump [built in check valve].
    Also halfords have a relay HEF560 relay 12 volt 40A 4 pin inc Diode as this is recommended for fuel pumps.( Don’t know if this is correct relay.)
    Question is as the terminals are marked 87, 86, 85 and 30. How do I connect up.

    9333501B-521C-4CA5-9342-5BB4E346E09D.png 2D0C5CC3-08D5-485B-AF85-AFFA06468B91.png
     
  12. Zed

    Zed Gradually getting grumpier

    There is a wiring diagram on the side of the relay...
    30, 87 is the load you want to switch, 85, 86 is the signal that switches it.
     
  13. Chrisd

    Chrisd Supporter

    As @F_Pantos reminded me, I need to get my posterior into gear and fit my cut off switch - which came with no instructions. Further investigation online drew a blank. So before I set it up, can those in the know check my assumptions. Pictures attached.
    IMG_20220112_140947~2.jpg IMG_20220112_141411~2.jpg
    I am powering this via my fuel pump relay. So does the 12vDC connector on the solenoid go to #87 on the relay?

    What does the "8" on the solenoid mean...is that to earth?

    Finally, if "8" is not to earth do I need to screw the metal fixing plate to earth?

    Thanks
     
  14. The solenoid will have two connections to energise it, Chris. One for switched live (12vdc) therefore, by process of elimination, the '8' must be ground or earth.
     
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  15. Chrisd

    Chrisd Supporter

    Thanks Andrew, that is what I thought, but it's nice to check and have confirmation. :)
     
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