Fuel Pump Relay Power


Information and questions on GL1200 Goldwings (1984-1987)
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rdraidr
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Joined: Fri Aug 19, 2011 7:02 am
Location: Roswell, New Mexico
Motorcycle: 1987 GL1200A

Fuel Pump Relay Power

Postby rdraidr » Sun Jun 10, 2012 9:11 pm



My fuel pump works fine when wired direct to battery 12V. I tested the voltage from the relay. There is no voltage measured when the key is off or switched on, but no start is attempted. As soon as I push the starter button, the voltage drops to a (-) number; i.e. -.02V. When I let off of the starter button, the voltage jumps to 1-5 Volts and then jumps back to (-) until it settles to 0.

I assume I have a bad relay; perhaps not.

Is there anyone out there that has successfully found a switched power to operate the pump? The only consequence I can think of is the fuel pump would be active any time the switch is on. But why would this be an issue? Fuel pump would burn up? Hard to believe.

Thoughts?



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virgilmobile
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Re: Fuel Pump Relay Power

Postby virgilmobile » Mon Jun 11, 2012 3:25 pm

The relay can be bypassed at the relay to test the rest of the circuits,eg,fuse,switches,pump, by jumping the white and black wires at the relay plug.
The idea was to kill the pump if there was ignition loss.Thus the sense wire from a coil that feeds the relay.
The relay is special.not just a clicker auto type,so if it's bad,you have 2 choices.
1. replace it
2. wire in a standard fuse protected relay to the battery and operate the relay from the kill switch line.
NOTE>>>>this method will not kill the pump should the engine stall,just if you kill the switch.
And there in lies the liability and loss of the safety feature.
If my engine dies..I really want the pump to die as well.

If the relay checks bad,you could attempt to gut it out and see if just the contacts are nasty and can be resurfaced.

rdraidr
Posts: 75
Joined: Fri Aug 19, 2011 7:02 am
Location: Roswell, New Mexico
Motorcycle: 1987 GL1200A

Re: Fuel Pump Relay Power

Postby rdraidr » Tue Jun 12, 2012 7:28 am

Just to be clear, if the relay is "not just a clicker auto type", how would I check it?

I assumed one of the three wires would be a hot 12V, the other two wires to be at 0V. When the starter is depressed, I would expect to see a voltage on one of the other wires that energizes the relay coil thus allowing voltage to the pump? The relay would be a normally open version.

The only failure is the delivery of the voltage from the ignition system or a relay that has a bad coil thus not allowing voltage out. All assuming there is 12V supplied.

Thoughts?

Thanks

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virgilmobile
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Re: Fuel Pump Relay Power

Postby virgilmobile » Tue Jun 12, 2012 11:48 am

Correct.I'll check the schematic but I think one is 12 volts power one is the trigger wire from the ignition coil and then the switched output to the pump.it should have 12 volts only when there is spark while cranking or running.

rdraidr
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Re: Fuel Pump Relay Power

Postby rdraidr » Tue Jun 12, 2012 7:38 pm

The schematic I'm following is for my '87 Aspencade.
The three wires are:
From the relay to the pump - Black/Blue; I checked continuity to the conector for the fuel pump - OK
Black/ Light Green - 12V when key switch was on.
Blue/ Yellow - .12V when switch was on; dropped to .06 when I hit the starter button (I did disconnect the starter).
Ground wire from the pump connection to battery negative was good.
I checked the Ign. Fuse (10A) - it was good at 12V across.

I've made a jumper and plugged it into the harness where the relay would go. I've jumped the Black/Light Green to the Black/Blue, so I should now have 12V to the pump when the key is on.

I also checked the same Blue/Yellow wire at the coil. Same reading for condition as above. I assume the bike has to be turning to get the pulses generated for the voltages needed.

The bike did run when I jumpered the pump to the battery and forced fuel in. So, I'm not looking for the Ign. Module to be bad.

Thanks.

rdraidr
Posts: 75
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Re: Fuel Pump Relay Power

Postby rdraidr » Tue Jun 12, 2012 8:58 pm

Just to follow-up, I put it all back together with the jumper in place. Turn the key on, hear the pump pulsing away, apply the choke hit the starter button, and bam!, fires right up.

Not sure what to think about the relay. Had a spare from another working bike, but nothing different.

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virgilmobile
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Re: Fuel Pump Relay Power

Postby virgilmobile » Tue Jun 12, 2012 10:01 pm

Can you share the schematic?The only 1200 schematics I have use a different color code.Mine is a 84 carb type with a pulse type fuel pump.It has 12 volts continuous,one wire goes to the ignition coil so it also has 12 volts which slightly pulses the meter when idling.And the 3rd,a white wire feeds the pulse pump.
this white wire will only provide power when the ignition is firing(engine running).
This wire only has volts when the pump is pulsing and is very short in duration.With a volt meter it almost reads 3 or 4 volts.In fact it actually goes to 12 volts but is so short that the meter can't jump that fast.I used a test light to prove out the relay. Here's the video with the pump hooked up and measuring the wore to the pump.


And a video with the pump unplugged and using a test probe to simulate a pump.There is no actual voltage on the wire until a load is applied.eg the pump.


rdraidr
Posts: 75
Joined: Fri Aug 19, 2011 7:02 am
Location: Roswell, New Mexico
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Re: Fuel Pump Relay Power

Postby rdraidr » Wed Jun 13, 2012 1:58 pm

Wow, this took considerable effort from my daughter to load. I have the manual on a PDF format, but this is a snapshot of the page. The colors stated match mine.

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virgilmobile
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Re: Fuel Pump Relay Power

Postby virgilmobile » Wed Jun 13, 2012 4:08 pm

Sorry,It didn't load.Be sure the snapshot is in a "jpg"format and below 1 mb.
I use Paint to size it and convert.
Or just PM me and send it in a E-Mail

rdraidr
Posts: 75
Joined: Fri Aug 19, 2011 7:02 am
Location: Roswell, New Mexico
Motorcycle: 1987 GL1200A

Re: Fuel Pump Relay Power

Postby rdraidr » Thu Jun 14, 2012 5:51 pm

I sent you a PM, but have not seen a reply.

The diagram is really simple. Three wires in, Black/Light Blue - 12V switched, Blue/Yellow - signal wire from ignitor (goes to coil), Black/Blue to fuel pump.

Green from pump to ground.

Thanks for the effort.

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virgilmobile
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83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: Fuel Pump Relay Power

Postby virgilmobile » Thu Jun 14, 2012 6:21 pm

I just double checked.No PM has arrived.
I can only assume that the function of the relay would be the same.look at the videos I made.
Mine will only show continuous volts when I use a test light on the pump wire.a volt meter shows near 0 volts until the pump is operating.we can talk on the phone if it will help.

rdraidr
Posts: 75
Joined: Fri Aug 19, 2011 7:02 am
Location: Roswell, New Mexico
Motorcycle: 1987 GL1200A

Re: Fuel Pump Relay Power

Postby rdraidr » Fri Jun 15, 2012 7:32 am

Your videos are excellent and show how to test the system. I plan on running the same tests this weekend, hopefully. I get busy and have to jam this personal time in where I can. Thanks so much for the input.

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virgilmobile
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Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
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78 GL1000
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82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: Fuel Pump Relay Power

Postby virgilmobile » Fri Jun 15, 2012 7:43 am

Also ,you don't have to test right on the relay,it can be tested at the pump plug.
With it unplugged from the pump you probe the hot wire and ground with the bike running.
It should light the test lamp for as long as you probe it.




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