83 VF750F fuel pump relay issues

Discussion in '1st & 2nd Generation 1983-1989' started by CWB, Aug 10, 2010.

  1. CWB

    CWB New Member

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    As the title says, I have an 83 VF750F with a fuel pump issue. I assumed a few things in this process so please correct me if Im wrong. I couldnt get it to pump fuel so per the service manual, I jumped the black and white wires and it pumps. Next, rather than check the continuity of the blue wire from the ignition module, I assumed (maybe my 1st mistake now that I think about it) that since I measured 14 volts at the relay connector with the voltmeter connected between the blue and black wires with the ignition key on, that the wiring is good and it must be the relay (assumes black is the ground). Rather than spend $40 on a new relay, yesterday I tried wiring a $10 4 pin 12v 40 amp, normally open until its energized automotive relay instead but didnt have anymore luck in making it work. To do so I simply wired the grounds together, then used 3 jumpers to connect into the stock relay connector/harness. Can anybody help with any suggestions as what else to try/check? Id like to attempt to fix my wiring and use a relay before modifying it too much. Also, will it hurt the pump if I simply jump the circuit on a permanent basis between the white and black wires? Does the pump on these ever actually shut off during normal operation because of lack of fuel demand? Thanks, Carl
     
  2. 83 Geezer

    83 Geezer New Member

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    Ever fix your problem?


    I am having the same problem, can be riding on the freeway and it will just cut off.
     
  3. squirrelman

    squirrelman Well-Known Member

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    Just eliminate the relay by bypassing it, using an insulated jumper wire at the relay plug.
     
  4. Glenn Lilley

    Glenn Lilley New Member

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    Did you sort out your fuel pump relay problem CWB?

    I am slowly working my way through my VF750F cleaning the contacts and link plugs using a product called De-oxit (fearfully expensive, but seems to do a good job!). Ran through the diagnostic tests, pump works fine with a jumper in the relay plug, Continuity exists between blue wire at relay and spark unit, but relay is non-functional when plugged in as fuel pump doesn't function! According to my manual, that means the relay is stuffed.

    Any suggestions other than buying genuine? Obviously this relay is solid state as evidenced by the circuit diagram so a standard relay probably doesn't work as you found out.
     

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