Fuel pump relay voltage

[wrs3]

Relay output voltage goes up and down 13.4 to10.8 and sometimes shuts down bike. Usually can restart after cool down .Does this sound like a bad relay?

 

[DreamV4]

bad fuel pump can suck too much current. Check resistance specs.

 

[desert_max]

Have you confirmed that you're only seeing this voltage drop at the fuel pump? If so, DV4 is on the right track - but make sure other point load supplies are not also falling off before an indictment.

 

[DreamV4]

Connect voltmeter to input and output relay wires and check voltage.

 

[wrs3]

Yes battery voltage is constant at 13.8. Fuel pump is good i have isolated it from relay, had bad diode pack replaced that, when bike quits and i try to restart neutral light and head light go out.Does the relay get its power from yellow wire? Looking at wiring diagram i not sure.

 

[desert_max]

Do you get the same voltage drop across the relay with the fuel pump disconnected? If so, then it is likely the relay. If not, could be crappy connections (or wiring) on the load side.

 

[wrs3]

Yes voltage drop is the same without fuel pump. Most of the time the voltage is 13.2 from the back of relay then it can drop below 12 for maybe a second then it goes back to 13+ then maybe 12.4 for a second then back up.I hate to buy a new relay at $125 or so, i think it is in the wiring. This morning i moved wiring and it seemed to affect it but before i could locate witch wire it stopped affecting it. I have along history with this yellow lemon i have replaced major connectors , gang green wiring,stator, R&R, fuel pump, relay it never seems to end I wish I didnt like thrill so much. Thanks for the reply.

 

[desert_max]

Lol. Good luck with it. I am an electrical engineer and I still hate Motorcycle harness gremlins.

 

[DreamV4]

There is electronic relay(4 pins), used for Lincoln Navigator air suspension. It is good for gazillion amps. I would try to install it. But OEM has 6 pins, I think, so first we need to figure out how each pin works

black ground
r/w ign plus
pulse ground gray from ign.
r/green input
green stops output if grounded
ppl output

 

[steve.o.strickland47]

Relay output voltage goes up and down 13.4 to10.8 and sometimes shuts down bike. Usually can restart after cool down .Does this sound like a bad relay?

It definitely could be a bad contact in the relay.

 

[RempageR1]

It definitely could be a bad contact in the relay.

What is the input voltage for the relay? Same thing? If input voltage is fine, then I also would say it`s the relay.

 

[sdt354]

Relay output voltage goes up and down 13.4 to10.8 and sometimes shuts down bike. Usually can restart after cool down .Does this sound like a bad relay?
I'd check the reserve switching / fuel sender circuit too, before replacing the relay. Maybe next time the bike is in no start mode, bring an alternate power source to the relay and see if she fires up.

 

[wrs3]

DreamV4 & sdt354 thanks for input I will try alternate power source to red green wire next time it stops , will also monitor voltage at that wire. Will look into green wire to see if that could be a problem that could be eliminated. I have checked fuel reserve circuit seems ok but I run on reserve always just in case.