2007 VFR800 fuel pump won't prime...

Discussion in '6th Generation 2002-2013' started by Skipper222, Jun 12, 2023.

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  1. Skipper222

    Skipper222 New Member

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    Hi All,
    my bike recently started stalling out at intersections (all in one day) and then refused to start at all the next day. Became clear the fuel pump wasn't priming. Read through the forums and did the standard checks such as the fuel cut relay, engine stop relay, bank angle sensor, ECM, etc to no avail. I even though maybe this bike has the HISS (Honda Ignition Security System) setup and maybe I had the wrong aftermarket ignition switch installed. (But why did it run previously? Maybe eventually the computer failed.) Turns out that if you don't see an HISS indicator on the instrument panel, your bike is not configured for HISS. Eventually, was able to identify the problem (which I had not come across in my google searches). There is a 30A fuse that is connect to the battery that is connected in parallel with another 30A fuse that feeds power from the battery to the starter relay switch. This first 30A fuse actually supplies power to the engine stop relay! This wire was heavily corroded and eventually overheated. I replaced the damaged wiring and 30A fuse housing and now the bike starts and runs!
    Attached are photos of the relevant section of the wiring schematic and a photo of the corroded wire. motorcycle wiring corrosion 1.jpg motorcycle wiring corrosion 2.jpg
     


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  2. Grum

    Grum New Member

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    Yep Main Fuse B 30amp, is a fairly common failure, it feeds the Engine Stop Relay main contacts then onto all your EFI stuff including the fuel pump. Symptoms will be a dead engine, no fuel pump prime and Fi light fully on.
    Here's another example of how bad the fuse and wiring can get.
    Well done in getting it all sorted.

    Just for info looking at your yellow hi lighting at the Starter Relay - Main Fuse A in the Starter Relay is not connected to the Green/Red relay coil wire, this would actually create a dead short situation. The tag off the fuse only feeds the Red Wire and the vacant spare 4th terminal at the Relay. The original drawing is mis leading, confusing the standard graphic for a 4p connector and looking like it's linking a wire that isn't! Drawing attached of the Starter wiring shows it better.
     
    Last edited: Jun 12, 2023


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  3. bmart

    bmart Insider

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    Nice work diagnosing and being curious! I'd like to know if a mounted voltmeter would have seen this failure coming or not. Anyone? Bueller?
     


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