Fuel problem again

Joined
Jul 8, 2008
Messages
186
Location
Vernon BC, Canada
Bike
2007 ST1300
STOC #
8025
After WeSToc in Fortuna Ca the bike started acting up in hot weather < 95'F . It was either no go or full throttle. The consensus of the forum was the fuel pump. I replaced the pump and all was good.
Yesterday, for the first time since replacing the pump, the temp hit 98'F. The bike rode fine, no hickups, until I shut it off to talk to a fellow rider. It would not start. It didn't attempt to start.

We pushed the bike into a shady area. I opened the gas cap and there was no pressure buildup. I still had 3 bars left on the gauge.

I removed the spark plugs and they were dry. Looking good.

I turned the key on and listened for the fuel pump to wind up. All I heard was the click of a relay and a few seconds later another click. The bike would not start.

We left it sit for 10 min and tried it again. the fuel pump pressured up and the bike started.

We were only 1 mile from home. Once there I shut off the engine and then tried to start it. Click, click. No pressuring up.

This morning tried it and it pressures up fine.

I don't want to be worried about riding in areas where it might get over 90'F.

I did replace the filter with the pump.

Any suggestions.

2007 ST1300 100,000 miles
 

Blrfl

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I turned the key on and listened for the fuel pump to wind up. All I heard was the click of a relay and a few seconds later another click. The bike would not start.
Just to rule something obvious out, will the battery pass the on-the-bike load test (system voltage stays above 10 while cranking the starter)?

--Mark
 
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'06 ST1300A
The bike rode fine, no hickups, until I shut it off to talk to a fellow rider. It would not start. It didn't attempt to start.
All I heard was the click of a relay and a few seconds later another click. The bike would not start.
Not sure what you're describing here. Did the fuel pump fail to operate, or did the starter motor fail to operate?

If the fuel pump failed to run, but the starter motor was able to spin the engine in an attempt to start, then the fuel delivery system bears investigating.

However if the starter motor is unable to spin the engine, then as Mr Blrfl suggests, it's time to check the battery condition. The simple test is to attach a voltage meter to the battery terminals (this is a good time to check that the battery terminal connections are clean and tight), and watch the voltage changes as the engine is started. Typically if the voltage drops below 10.0 volts during starter motor engagement, then it's time to replace the battery.
 
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Bill144
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Vernon BC, Canada
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2007 ST1300
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8025
QUOTE: Anna'sDad If the fuel pump failed to run, but the starter motor was able to spin the engine in an attempt to start, then the fuel delivery system bears investigating.

It was the fuel pump that did not pressure up. I did hear the relay come in but no pump. The battery is ok.
 
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Millgrove, ON, Canada
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2016 Versys 1000
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A relay can click but the higher current contacts on the pump side may be faulty, possibly intermittent... I'd replace the fuel pump relay. Since your starter is cranking, we can rule out the side stand switch, and emergency stop switch.
 
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North Plainfield, NJ
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'06 ST1300A
I did hear the relay come in but no pump.
If it is the Fuel Cut-Off Relay that you hear clicking, then that's helpful in tracking down the fuel pump issue.

The Fuel Cut-Off Relay is one of the few relays that utilizes the same +12vdc source to energize the coil, as well as supply the voltage to operate the fuel pump. So when you hear the relay click, you know supply voltage (for the fuel pump) is passing through the relay (barring the possibility of bad relay contacts), on to the fuel pump. It is a Brown conductor (wire) that passes voltage from the Fuel Cut-Off Relay to the Fuel Pump, given the close proximity of the the relay to the fuel pump, it should be easy to check the wire for any damage.

Apparently the fuel level sensors also receive +12vdc from the same Brown conductor (as the Fuel Pump}, perhaps this fact will aid in diagnosing whether or not the Brown conductor is performing properly by checking to see if the fuel gauge is operating when the fuel pump fails to start.
 
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Bill144
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Vernon BC, Canada
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2007 ST1300
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8025
If it is the Fuel Cut-Off Relay that you hear clicking, then that's helpful in tracking down the fuel pump issue.

The Fuel Cut-Off Relay is one of the few relays that utilizes the same +12vdc source to energize the coil, as well as supply the voltage to operate the fuel pump. So when you hear the relay click, you know supply voltage (for the fuel pump) is passing through the relay (barring the possibility of bad relay contacts), on to the fuel pump. It is a Brown conductor (wire) that passes voltage from the Fuel Cut-Off Relay to the Fuel Pump, given the close proximity of the the relay to the fuel pump, it should be easy to check the wire for any damage.

Apparently the fuel level sensors also receive +12vdc from the same Brown conductor (as the Fuel Pump}, perhaps this fact will aid in diagnosing whether or not the Brown conductor is performing properly by checking to see if the fuel gauge is operating when the fuel pump fails to start.
Tomorrow it is supposed to be very hot again. I will search out the hot wire from the relay to the pump, once identified I will take the bike for a ride. I will make sure that before I shut down I will be at home. If it won't start, I will check the wire that is supposed to be hot. That should tell me that its the relay.
 
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Bill144
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Vernon BC, Canada
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2007 ST1300
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8025
Well it acted up again - Checked all wiring - no teeth marks - replaced fuel shutoff relay - bike started OK. Rode about 30 kms and as i approached a stop sign the engine shut down. Tried to start and it was a no go. I could not hear the fuel pump pressuring up but I could hear the relay come on and after a few seconds it clicked off.
I called for a tow home, there I could test if the pump was getting power. By the time we got home the bike was OK again.
The temp was mid 70's so not like the first time.

I guess I'm going to have to run it for a while in the driveway to see if it will act up so I can better diagnosis the problem.
 

Coop

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Good luck getting it running Bill. Rose isn't messing with it when you aren't looking......is she?
 

SupraSabre

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I really haven't messed with the relays too much, but there is a whole bank of them (7 actually) under the leftside cover. Find which is the fuel relay and swap it with one of the others. See if that causes a new problem while solving the other.

All those relays are the same.
 
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Bill144
Joined
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186
Location
Vernon BC, Canada
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2007 ST1300
STOC #
8025
I really haven't messed with the relays too much, but there is a whole bank of them (7 actually) under the leftside cover. Find which is the fuel relay and swap it with one of the others. See if that causes a new problem while solving the other.

All those relays are the same.
I have done that. The only difference is the bike quit running on its own in mild temps rather than not start after I shut it down. I have to shut it off and then wait for it to cool off. I know the battery is good - I believe the relays are good - my next move may be removing the pump and check to see if I didn't fit the wires correctly.
What bothers me is that it corrects itself after time. I'm lead to believe that something heated up, trips a thermal device and then resets after cooling.
I don't believe the pump has that so I'm stumped.
 

RCS

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Possibly try electric contact cleaner on any electical connection opened during the fuel pump replacement.
 
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Bill144
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186
Location
Vernon BC, Canada
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2007 ST1300
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8025
I need a little help. While checking out the fuel pump assembly (its still in place) I notice I get a resistance from the top of the reserve tank to ground IF the ground wire is disconnected. With all the metal studs and nuts holding down the top cover I would think the resistance would be 0 ohms. With the ground wire disconnected I get 1.233K ohms.
Again the problem is the pump will not work after I go less than 50 miles. The fuel pump relay does click on and off but the pump doesn't run.
When I disconnected the ground wire from the pump, the pump will not run. I am wondering if a ground connection somewhere is bad or loose or intermittent.

So, if someone could remove the front seat of their ST and remove the ground wire from the top of the reserve tank (green) and take a ohm reading from the gnd on the tank to the battery gnd and record if there is a resistance.

Better yet - pull the ground wire off the top of the reserve tank and see if it will start.

Thanks
 
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