Fuel pump/relay

Not having it!
93VFR750
Fuel Pump has not run on its own since I have had it
I have trouble shot the wiring relay and pump to the best of my knowledge
Continuity on red/yellow from relay to coil and starter
12 volts on black wire
No voltage on blue/ black when cranked
Spark at #4 plug
Voltage drop from 12 to around 5 volts on red/yellow when cranked
No click from relay
Wired relay connector both ways as seen in pics
All pumps in picture run when jumped. The first relay on the left is OEM new, the second one is OEM to the best of my knowledge the other two are aftermarket, The ECM has been chnged out with a used one
All with the same negative results!
I know , I know I could switch it!
How does the pump know when to run without it
Any insight would be appreciate it!

_signed prolific parts changer

 

When what is jumped? Power directly to the pump, or the blk and blk/blu wire at the Fuel Cut Relay connector?

The relay gets energized when the bike is being cranked or running and 12v is sent via the r/y wire. Just switching on the ignition does not energize the relay. It gets power from the ignition system (spark is being produced).

If 12v is being sent under those conditions and the pump operates when blk and blk/blu wire are jumped with the key on, it has to be a relay problem.

If you are not getting 12v at the r/y when cranking, then there is a problem in the wire harness or ICM. I doubt you would get two ICM with the exact same problem, but while improbabale, it is not impossible.

 

Yes attached the black/blue to the pump with the black 12v power and all of the pumps pictured run
and yes I cranked the bike while testing
4 bad relays and two bad ECMs?

 

No. Sounds like your harness is damaged somewhere om the r/y run.

Or bad / WRONG relays. Not all FCRs are pinned the same.

Time to check for continuity on the r/y line from the ICM to the relay, and other connections.

Testing what exactly? So you confirmed you do not get 12v at the red/yel wire when cranking?

 

Voltage drop from 12 to around 5 volts on red/yellow when cranked
Continuity on red/yellow
I made a jumper wire that went from coil to relay that included ecm trigger r/y
Wired relay connector both ways as seen in pics . Which wiring is right for model year?

 

Voltage drop when cranked? You shouldn't have any voltage on red/yel until cranked.

Your "jumps" do not seem to be what I'm talking about.

Also, have you noticed that the blk and red/yel wires are in the wrong positions on the connector for an original relay?

Don't try and introduce voltage from another source to the red/yel. Pin the connector correctly for an original relay. 12v on red/yel WHEN CRANKED to energize a working relay which then connects blk & blk/blu. Pump should run if blk and blk/blu are jumped with key on to test if pump is operational. That's it.

 

The pump doesn't know "when" to run without the relay. It simply will (can) run with blk & blk/blu jumped and the key on. But it will know when to stop running. It's when a certain fuel line pressure is reached, as in carbs full and float valves shut, and the built in pressure switch stops it.

That's why you can jump the relay connector and run a bike normally without one, or put blk & blk/blu on a toggle. The FCR is designed to stop the pump from running in the event of an accident and the fuel lines are compromised (or the orientation of the crashed bike prevents the float valves from stopping fuel flow), so it doesn't continue to pump fuel into a bad situation with just the key on,