How to test loss of power to fuel pump


Information and questions on GL1500 Goldwings (1988-2000)
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okie2ee
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Motorcycle: 1992 Honda Goldwing 1500 Interstate
1986 Yamaha V-Max
1994 Yamaha V-Max

How to test loss of power to fuel pump

Post by okie2ee »



My trike suddenly won't start. Checked the fuel pump and it is pumping fine. No power to the fuel pump.............what items do I need to check related to loss of power? I'm looking to take the easy way out and utilize the vast knowledge base here to quickly isolate the problem...........thanks in advance



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bluthundr31
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Motorcycle: 1991 GL1500 Interstate (Cinnamon Beige)

Re: How to test loss of power to fuel pump

Post by bluthundr31 »

okie2ee wrote:
Thu Apr 04, 2019 10:18 pm
My trike suddenly won't start. Checked the fuel pump and it is pumping fine. No power to the fuel pump.............what items do I need to check related to loss of power? . . . .
OK, did you hook 12V directly to your fuel pump & run the "output" hose (going up to the fuel filter) into a beaker/measuring device to make sure its pumping and you're getting the proper flow? OR, did you pull the fuel pump and hook it to 12V on a "bench" to bench-test it, and it is pumping fine??

The fuel pump on your '92 will start pumping for a couple seconds AFTER the "start" button is hit and the ignition is on. If the engine starts, then the ECM will continue to power the fuel pump as needed to keep the bike running. IIRC, the black wire on top of the fuel pump flange is the 12V power, and the green wire is the ground. You should be able to test each wire for power, , and continuity to ground easily with a multi-meter/voltmeter.

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okie2ee
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1986 Yamaha V-Max
1994 Yamaha V-Max

Re: How to test loss of power to fuel pump

Post by okie2ee »

Thanks for your response, I did test the fuel pump both in and out of the bike, the fuel pump was working fine based on the recommended fuel delivery. An important piece of information was the running of the fuel pump for several seconds when the start button is engaged. I next suspected the fuel shut off valve might be blocking the fuel flow. I had disassembled the valve previously and it was working OK prior to putting the bike up for winter. I had already purchased a new diaphram kit so I proceeded to rebuild the shut off valve. Upon disassembly, I found a damaged diaphram, it apparently pulled away from the edge of the housing and started to leak causing the valve to not open.




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Charlie1Horse
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1992 GL1500I Interstate

Re: How to test loss of power to fuel pump

Post by Charlie1Horse »

But, that won't help if you're not getting power to the pump. Check your kill switch. Many miles and years of vibration at the handlebar can cause the power connections under that switch to be loosened. I had the same trouble on the road and had to be towed home. It took several days for me to narrow the problem down and found that both connections under the kill switch were slightly loose. I tightened them and have never had any more trouble.
Russell

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Those who say it cannot be done should try not to interrupt those who are doing it.

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okie2ee
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Motorcycle: 1992 Honda Goldwing 1500 Interstate
1986 Yamaha V-Max
1994 Yamaha V-Max

Re: How to test loss of power to fuel pump

Post by okie2ee »

Forgot to mention that after I replaced the diaphragm the bike started right up with no problem.............I was getting power to the pump..............but I need to put the kill switch on my list of things to check in order to avert future problems...........thanks

CRAFFS
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Motorcycle: 1993 Honda Goldwing GL1500, 1975 Suzuki GT750, 1979 Yamaha SX750

Re: How to test loss of power to fuel pump

Post by CRAFFS »

Good afternoon from Cape Town,
My 1500GL (1993) has been "standing" for 2 years. Fitted a new battery but "no start". I wish to first follow "BLUTHUNDR31's" advice (his post 5 April 2019) to "hook 12V directly to the fuel pump". BLUTHHUNDR31 refer to "the black wire on top of the fuel pump flange is the 12V power, and the green wire is the ground". On my 1993 model there are 3 wires/connectors. The one connector has a white/blue wire and "W" stamped on the flange next to it. The other 2 connectors differ in size and I cannot see the wire colors (the wires are inside black "sleeves" and I do not wish to cut the sleeves. The bigger connector has a "B" stamped on the flange next to it while the smaller connector has a "G" stamped next to it. Which wires are the "12V" and "Ground"? Thank you.

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DenverWinger
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Re: How to test loss of power to fuel pump

Post by DenverWinger »

The Blue/white wire is your low fuel light. The B and G terminals would be the pump, G probably ground and B probably +12v. You can check with a volt meter or test light while cranking starter.


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bellboy40
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Re: How to test loss of power to fuel pump

Post by bellboy40 »

The big wire toward the front with a single wire going to a connector is the +battery lead. I believe it is labeled "B". The wiring diagram shows it to be a blue wire but it looks black to me. Just pull that wire off the connector and jumper +12 volts to the terminal and your pump should run. It is already grounded so you only have to use the one wire for the pump to run.

CRAFFS
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Re: How to test loss of power to fuel pump

Post by CRAFFS »

Thank you DenverWinger & Bellboy, I followed your advice and found the fuel pump to be "dead". I will now remove the pump by following the steps as per my workshop manual. However, my workshop manual does not show any steps after pump removal?. Only how to re-install the pump?? :((. Anyway, I will see if the pump can be disassembled, maybe I will find something otherwise will have to start "hunting" for a replacement pump...

CRAFFS
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Motorcycle: 1993 Honda Goldwing GL1500, 1975 Suzuki GT750, 1979 Yamaha SX750

Re: How to test loss of power to fuel pump

Post by CRAFFS »

Ok, I have removed the fuel pump. I "bench tested" the pump after checking that the Ground & 12V wires are in good condition. Pump (motor) still "dead" but I am not giving up yet :)). Must mention the pump filter is very dirty (due to rust in the upper half of the petrol tank?). I have removed the rear cover of the pump unit and opened the small metal "fingers" that holds the pump motor in position. Before I continue trying to remove the motor, anybody who tried to do this? (removing the motor) or should I just start sourcing for a replacement fuel pump. Thank you.

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bellboy40
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Re: How to test loss of power to fuel pump

Post by bellboy40 »

Here is a link to how to replace the fuel pump with an after market pump. Reason being the original equipment pumps are pretty expensive but also very reliable. Anyway it has a lot of detail about how to do it as well as some good pictures.
http://www.berrysweb.com/1500_fuel_pump.htm

CRAFFS
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Motorcycle: 1993 Honda Goldwing GL1500, 1975 Suzuki GT750, 1979 Yamaha SX750

Re: How to test loss of power to fuel pump

Post by CRAFFS »

Thanks a lot Bellboy!, I really appreciate!
Hopefully I will find one of the recommended pumps in South Africa, if not I will import from "somewhere".
While waiting for the new pump, I will continue checking the fuel system (electrical, vacuum hoses, petcock etc.).
By the way, I noticed on the original fuel pump that it is manufactured by Mitsubishi...
Thanks again & kind regards, Johann



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