Wiring issues after the fire damage fix.

[wayne z]

Hi all, I have just replaced the entire wiring harness on my Vmax after my old one nearly burned in two in the fuel pump area from a fuel fire.
Haven't pinpointed the cause yet, but I did discover that tank vent valve was clogged. I did find a lot of cracks in the fuel pump diaphram, and the motor end of the pump was the most burned spot on the bike.
Speculating, maybe too much tank pressure (nearly full) causing something to leak in the motor area of the pump and the sparking contacs of the pump ignited the fuel.

The problems:
I carefuly inspected the replacement harness, cleaned the connectors and repaired a few. There was no evidence of overloaded or short circuit wires or connectors anywhere in the burned harness, just an 8" section burnt to bare copper.

After installation, all the electrics work, but the fuel pump and the servo are silent when the key is turned on.

I jumpered the pump and it's fine. Close re-inspection of all plugs and fuses checks OK.

My guess is that when the wires shorted together in the fire area, probably burned out some relays.

Does anyone want to opine on what parts I should try replacing first? Also, a description of their locations would be helpful.

Thanks,

Wayne

 

[one2dmax]

What does it do when you turn the switch to reserve?

 

[wayne z]

Switch to reserve changed nothing. Dash lights blinkers starter ect work.

I've been studying the schematic and I think I need to check the red/black wire at the relay connector plug for voltage, then work from there.

 

[one2dmax]

Also verify the fuses (main too above the battery). The reserve is the fuel pump override and bypasses much of the system. Do you hear the vboost cycle when you turn the key on?

 

[wayne z]

No Vboost cycling and no pump cycling. All fuses good, clean grounds everywhere. Gonna check for power at the main relay. If I find power there, I will check the relay outputs and go from there I recon.

 

[one2dmax]

Check the run/stop switch (it is in the run position right)?

 

[wayne z]

Pretty sure it was on, have been there and done that before but have to check when I go down to the basement . Will the starter still work if it is in the stop position? I know that it will on my 82 FLH.

 

[Redbone]

Pretty sure it was on, have been there and done that before but have to check when I go down to the basement . Will the starter still work if it is in the stop position? I know that it will on my 82 FLH.

The Vmax locks out the starter switch from working in the stop position.

 

[wayne z]

OK, I had power to the main relay, so I guess it is toast. I bought several different relays, main relay, fuel pump relay, diode and pressue sensor switch (package deal) from a vendor on ebay for $20 shipped.

 

[silverado6x6]

That is something to think about when you have a plugged up vent and an electric fuel pump, soon the pump will have to draw against a vacuum making it overheat. Never thought of that scenario on a bike as usually you are using gravity feed, but with a small tank and a thirsty motor then you have to start thinking like its a car fuel system. And i have seen those issues on a car, tank doesnt vent, serioysly affects fuel pumps outside the tank that are out in the open.

 

[wayne z]

So, is it possible a fuel pump could overheat if it cycled continuosly?
I did find one of the rubber valves unplugged and sideways, and the motor end of the pump was burned to a crisp along with everything within 2" of it which was the fuel line and wiring harness.