Have trouble with fuel pump system, possibly the spark unit.

What tells the pump ??

The moving, reciprocating coil inside the pump rests atop a diaphram, and when the diaphram can be depressed because there is a lack of fluid it triggers the contact points to close and power the coil to move to flex the diaphram repeatedly until it senses pressure.......or somethin' like that.

There ain't no mercury switch.

 

Thanks.
But why is it that the pump will operate (out of the system) but when it is IN the system with the good relay it still will not pump? (known good relay)?

 

Assuming pump and relay is good. there is only one other thing. The wires and or connectors. Some pin in some connector is not connecting.

So your getting 12v on two pins of the fuel relay when key is just on. After starting you should have 12v on two of the three legs of the relay. The third wire is coil signal which could be 12v also. In that case you should get 12v on all fuel relay pins when the bike is running. Two of those pin the 12v should fluctuate on -off. The pump only runs when #4 fires.

Even the wiring diagram from 90 to 96 VFR's have thew same fuel relay wiring hook up. Hard to believe the 87 is different. So from 83-96 they are the same setup. The 800FI use basically the same. Except they fire off the injectors instead of coil.

 

I need help, I kind of have the same problem on my 86 vfr700

I recently changed my fuel filter, then put everything together and now the fuel pump doesn't pump. When I connect gas directly to the carb, she runs like a champ, and the tube coming from the fuel pump doesn't spit any gas, but i can hear the pump clicking, does that mean the pump is working?

 

Most fuel filters have directional arrows or IN and OUT markings, so you need to confirm that it's flowing in the correct direction.

If pump clicks but no fuel comes out there's probably a blockage in tank or in fuel line between tank and pump, because pump is not getting gas.

 

My filter is in the right way, the only thing is its a 5/8 instead of a 3/4, i just bought a 3/4, so i ll put that in tomorrow, hopefully that will do it.
If not what else should I do?