I have an 84 GL1200 Interstate it was parked for 4 months because I was working over the road. I had started the bike a couple times in that 4 months just to keep it running. About a month ago I tried to start it to go for a ride and the fuel pump was not working. (last summer i had heard the pump ticking loud a few times so i was waiting for it to go out) so I bought a new pump and replaced it but the new one worked for about 15 seconds while cranking the motor and it stoped. So I finally found the relay and jumped around it and got nothing. So I ran 12 volt straight from the battery to the pump both old and new both and they both act like they are shorted out inside. I can open the points on the pump and hook up 12 volts and its fine but as son as I release the points and let them close I get heated wires and acts like it has a short. When Im hooking them direct to 12v I am doing so independant of the bike so im not burning up the wireing of the bike.
Any help would be wonderful. Thanks in advance
Fuel pump not working and doing crazy things
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kpritchett
- Posts: 3
- Joined: Sun Sep 17, 2017 6:11 pm
- Location: Farmington, MO
- Motorcycle: 1984 GL1200I
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virgilmobile
- Posts: 9102
- Joined: Sun Sep 19, 2010 5:39 pm
- Location: Denham Springs,La.
- Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I
Re: Fuel pump not working and doing crazy things
The pump is a very large solenoid.Kinda like the starter solenoid.Only this one takes a bunch of power to get it to move.
I think a #12 wire fused at 10 amp handles it.
As soon as power is applied,the plunger is snapped into the casing opening the points up.This movement operates the diaphragm inside pumping fuel.When the fuel pressure builds it stops the plunger from activating the points.
If the plunger does not move,the pump WILL draw a bunch of power.This is a pulse pump.Its suppose to activate fast and not stay energized.
If the plunger is not moving there's 2 possible problems.
Either the pump is full of trash or the damper ring(the noise reducer) has come apart and jammed the plunger.
The second is the coil has burnt up and shorting to the case.Possibly from either of these problems.
Test by pushing the plunger in.I think it travels about half inch or so.it should move freely with just some spring pressure on to.
I did a post about fixing a ticking fuel pump.May want to read about it.
Normally when power is applied,the pump cycles about 2 times per second when there's no fuel.As the pressure builds,it slows to a stop.
Also the fuel relay is peculiar.It does not have power coming out of it like a normal relay.It is a special circuit and will only show volts when there is spark and a power demand from the pump.It also just pulses the test light when working properly and hooked to a working pump.
I think a #12 wire fused at 10 amp handles it.
As soon as power is applied,the plunger is snapped into the casing opening the points up.This movement operates the diaphragm inside pumping fuel.When the fuel pressure builds it stops the plunger from activating the points.
If the plunger does not move,the pump WILL draw a bunch of power.This is a pulse pump.Its suppose to activate fast and not stay energized.
If the plunger is not moving there's 2 possible problems.
Either the pump is full of trash or the damper ring(the noise reducer) has come apart and jammed the plunger.
The second is the coil has burnt up and shorting to the case.Possibly from either of these problems.
Test by pushing the plunger in.I think it travels about half inch or so.it should move freely with just some spring pressure on to.
I did a post about fixing a ticking fuel pump.May want to read about it.
Normally when power is applied,the pump cycles about 2 times per second when there's no fuel.As the pressure builds,it slows to a stop.
Also the fuel relay is peculiar.It does not have power coming out of it like a normal relay.It is a special circuit and will only show volts when there is spark and a power demand from the pump.It also just pulses the test light when working properly and hooked to a working pump.
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virgilmobile
- Posts: 9102
- Joined: Sun Sep 19, 2010 5:39 pm
- Location: Denham Springs,La.
- Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I
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kpritchett
- Posts: 3
- Joined: Sun Sep 17, 2017 6:11 pm
- Location: Farmington, MO
- Motorcycle: 1984 GL1200I
Re: Fuel pump not working and doing crazy things
Update: The relay has continuity all the time between the black and white wires.The plug in going to the fuel pump has ground on both wires at all times untill you crank the motor and then the black wire alternates from ground to power to ground and so on until you stop cranking the motor. Im a pretty good mechanic but im lost on this one.