System will not engage fuel pump to start and run
Thread Starter
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3rd Gear
Joined: Jan 2024
Posts: 7
Likes: 0
From: NC
System will not engage fuel pump to start and run
I've got a 2009 Sportster and it has ECM on back fender. the system relay will not make contact from the 87 and 30 on fuel pump and ignition. I've cut open a relay connection and put a rubber band around it to keep contact points touching and you have to remove the 30 amp main fuse to turn off fuel pump with ignition switch on. Now. I've tested fuel pump motor and continuity from fuel pump to harness and through switch . Switch tested fine with light bulb test on and off, triple checked my ECM wire to number and their correct from what I wrote down and what Harley gave me out of their book. The relays and fuses test fine but 85 and 86 to on/off switch and ECM. They are not getting power to make magnetic charge to connect the 30 and 87 (ignition to battery and fuel pump).
I need to find out what causes the fuel pump to quit after it runs for 2 seconds when waiting to crank up engine when it's working normal?
If I manually hold the relay shut it runs but fuel pump continually runs
Is the 30 amp green fuse inside battery cover stock OEM Harley or after market like dyna jet I don't remember from my last stock Sportster. I'm trying to figure if a stock wiring harness will fix the issue or how could it be a problem with ECM not telling the fuel pump to come on?
I need to find out what causes the fuel pump to quit after it runs for 2 seconds when waiting to crank up engine when it's working normal?
If I manually hold the relay shut it runs but fuel pump continually runs
Is the 30 amp green fuse inside battery cover stock OEM Harley or after market like dyna jet I don't remember from my last stock Sportster. I'm trying to figure if a stock wiring harness will fix the issue or how could it be a problem with ECM not telling the fuel pump to come on?
Road Master
Joined: Jan 2024
Posts: 808
Likes: 194
From: Trinidad
the ecm grounds the relay primary coil. So check for voltage to terminal 86 on connector side of the system relay (black and white wire) , this is the switched voltage. Then check for continuity from 85 terminal on connector to the ecm ( orange and green wire).
Last edited by paulmedford; Jan 27, 2024 at 02:04 PM.
Thread Starter
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3rd Gear
Joined: Jan 2024
Posts: 7
Likes: 0
From: NC
I've got a phone picture of their book. I can see everything the relay hooks to. I'm going to try and test where the power stops going to the relay today
Thread Starter
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3rd Gear
Joined: Jan 2024
Posts: 7
Likes: 0
From: NC
Just now I have tested continuity with the battery hooked up to see if it has voltage to light a bulb on the white wire w/black stripe from relay plug to the handle bar plug tank. Already tested right hand control switch continuity. The grey has continuity so does white w/ black stripe from relay to switch. Both switches work start and on. The green orange wire at system relay plug to ECM has continuity. The blue grey from plug to ECM has continuity the fuel pump works. I've tried new relays in both positions and it will only turn fuel pump on with the relay shut with a rubber band.
another thing the power drain comes from turning ignition off and it makes a noise at the throttle position sensor. I can unplug the sensor at top of intake and the noise stops.
I don't Have a voltage meter so I tested with a turn signal that I had laying around. If they have continuity they have power right. i don't understand what gives power to the fuel pump when needed and cuts off when needed. Because it won't always have power to the fuel pump when the relay disconnects the contact points.
another thing the power drain comes from turning ignition off and it makes a noise at the throttle position sensor. I can unplug the sensor at top of intake and the noise stops.
I don't Have a voltage meter so I tested with a turn signal that I had laying around. If they have continuity they have power right. i don't understand what gives power to the fuel pump when needed and cuts off when needed. Because it won't always have power to the fuel pump when the relay disconnects the contact points.
Road Master
Joined: Jan 2024
Posts: 808
Likes: 194
From: Trinidad
Just now I have tested continuity with the battery hooked up to see if it has voltage to light a bulb on the white wire w/black stripe from relay plug to the handle bar plug tank. Already tested right hand control switch continuity. The grey has continuity so does white w/ black stripe from relay to switch. Both switches work start and on. The green orange wire at system relay plug to ECM has continuity. The blue grey from plug to ECM has continuity the fuel pump works. I've tried new relays in both positions and it will only turn fuel pump on with the relay shut with a rubber band.
another thing the power drain comes from turning ignition off and it makes a noise at the throttle position sensor. I can unplug the sensor at top of intake and the noise stops.
I don't Have a voltage meter so I tested with a turn signal that I had laying around. If they have continuity they have power right. i don't understand what gives power to the fuel pump when needed and cuts off when needed. Because it won't always have power to the fuel pump when the relay disconnects the contact points.
another thing the power drain comes from turning ignition off and it makes a noise at the throttle position sensor. I can unplug the sensor at top of intake and the noise stops.
I don't Have a voltage meter so I tested with a turn signal that I had laying around. If they have continuity they have power right. i don't understand what gives power to the fuel pump when needed and cuts off when needed. Because it won't always have power to the fuel pump when the relay disconnects the contact points.
relay again. CHeck your bank angle sensor make sure it is working
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Thread Starter
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3rd Gear
Joined: Jan 2024
Posts: 7
Likes: 0
From: NC
With ignition on and switch off I get;
.65-.7 on 85 and 86
30 has 12.78 volts
87 has .01 volts
Does that mean the plastic relay conducts electricity between the connectors not bringing them to 0
Then when you hit the fuel pump switch on, it'll go to 12.09-12.11 volts on 85 and 86
30 has 12.69 volts
87 has .01 volts
85 and 86 go to the copper wire bundle and charge 30 to make a magnet. 87 isn't connected until 30 shuts to make with it. There's no magnetic charge on 30 when it's not plugged in but I can see it shut and function when there is a battery causing it to shut through 85 and 86.
It sounds like the relay is the problem like it isn't magneting shut. But it works for the starter. If there's power on 85 and 86 shouldn't that charge 30 with enough magnet to close to 87. I've tried 2 new relays
.65-.7 on 85 and 86
30 has 12.78 volts
87 has .01 volts
Does that mean the plastic relay conducts electricity between the connectors not bringing them to 0
Then when you hit the fuel pump switch on, it'll go to 12.09-12.11 volts on 85 and 86
30 has 12.69 volts
87 has .01 volts
85 and 86 go to the copper wire bundle and charge 30 to make a magnet. 87 isn't connected until 30 shuts to make with it. There's no magnetic charge on 30 when it's not plugged in but I can see it shut and function when there is a battery causing it to shut through 85 and 86.
It sounds like the relay is the problem like it isn't magneting shut. But it works for the starter. If there's power on 85 and 86 shouldn't that charge 30 with enough magnet to close to 87. I've tried 2 new relays
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Road Master
Joined: Jan 2024
Posts: 808
Likes: 194
From: Trinidad
With ignition on and switch off I get;
.65-.7 on 85 and 86
30 has 12.78 volts
87 has .01 volts
Does that mean the plastic relay conducts electricity between the connectors not bringing them to 0
Then when you hit the fuel pump switch on, it'll go to 12.09-12.11 volts on 85 and 86
30 has 12.69 volts
87 has .01 volts
85 and 86 go to the copper wire bundle and charge 30 to make a magnet. 87 isn't connected until 30 shuts to make with it. There's no magnetic charge on 30 when it's not plugged in but I can see it shut and function when there is a battery causing it to shut through 85 and 86.
It sounds like the relay is the problem like it isn't magneting shut. But it works for the starter. If there's power on 85 and 86 shouldn't that charge 30 with enough magnet to close to 87. I've tried 2 new relays
.65-.7 on 85 and 86
30 has 12.78 volts
87 has .01 volts
Does that mean the plastic relay conducts electricity between the connectors not bringing them to 0
Then when you hit the fuel pump switch on, it'll go to 12.09-12.11 volts on 85 and 86
30 has 12.69 volts
87 has .01 volts
85 and 86 go to the copper wire bundle and charge 30 to make a magnet. 87 isn't connected until 30 shuts to make with it. There's no magnetic charge on 30 when it's not plugged in but I can see it shut and function when there is a battery causing it to shut through 85 and 86.
It sounds like the relay is the problem like it isn't magneting shut. But it works for the starter. If there's power on 85 and 86 shouldn't that charge 30 with enough magnet to close to 87. I've tried 2 new relays
Road Master
Joined: Jan 2024
Posts: 808
Likes: 194
From: Trinidad
With the negative lead on ground and the positive on pin 85 of bike with the relay unplugged and the voltmeter on ohms….you should see a dip in the resistance for a brief period like in the video . This is how the ecm supposed to work so if you have good voltages then you have to check ecm. MAKE SURE ITS ON PIN 85 or you can damage your voltmeter
Last edited by paulmedford; Jan 29, 2024 at 04:26 PM.