2000 ST1100 Fuel pump relay location

[Buellboy]

Good evening guys,

I am new to this forum and looking for some help.

My 2000 ST1100 ABS UK let me down today. Luckily I didn't even make it out of my driveway.

She started fine like normal but as soon as the bike was warm and I closed the choke it died. I think I have traced the problem down to the Fuel pump shut off relay. The problem is I can find it?

My workshop manual says there are Relay is located behind the dash?

Can someone confirm the location and how to get to it please.

Thanks in advance

 

[dwalby]

this should help, from the Honda manual. What I'm not sure about is if you can get to that relay just by removing the windshield and the top panels, or if you have to take the top left fairing off to get good access. Others may chime in with that information.

 

[Uncle Phil]

Really need to remove the left top fairing IIRC when I did it.
To make sure it is the problem, run a fused hot to the pump (white terminal) to see if that fixes it.
There's a switched hot behind the ABS fuse block.

 

[Buellboy]

this should help, from the Honda manual. What I'm not sure about is if you can get to that relay just by removing the windshield and the top panels, or if you have to take the top left fairing off to get good access. Others may chime in with that information.

Great, thanks very much. Ill take a look tomorrow

 

[Buellboy]

Really need to remove the left top fairing IIRC when i did it.
To make sure it is the problem, run a fused hot to the pump (white terminal) to see if that fixes it.
There's a switch hot behind the ABS fuse block.

Thanks, sounds like a good check before taking the bike apart

 

[Buellboy]

Thanks again guys for the advise. I've confirmed the pump is working.

So after taking the panels off I managed to get to the relays. Am I correct in thinking the fuel cut off is the middle one labeled TF319?

Is there a simple method of checking the relay to see if its good or bad?

 

[dwalby]

those wire colors match the wiring diagram for the relay, so I think you have the right one.

can't help with the testing method, but I think others here have had issues with that relay so maybe one of them can help you test it. It appears to have two wires that come from the ignition module, presumably to energize the relay, I think the red wire provides power to the fuel pump, and the green wire is ground.

I'm assuming the bike isn't running currently, so the relay isn't going to energize from the ignition module to be able to check the voltage on the red wire anyway.

Also, one caveat, because that relay energizes off the ignition module, its probably digital logic voltage levels, not 12v, so don't try to jumper the relay with 12v, that will probably fry the relay.

the good news is new replacement parts are still available, the bad news is its pretty expensive ($80-100)

the part number is 36100-MN5-000

 

[Buellboy]

those wire colors match the wiring diagram for the relay, so I think you have the right one.

can't help with the testing method, but I think others here have had issues with that relay so maybe one of them can help you test it. It appears to have two wires that come from the ignition module, presumably to energize the relay, I think the red wire provides power to the fuel pump, and the green wire is ground.

I'm assuming the bike isn't running currently, so the relay isn't going to energize from the ignition module to be able to check the voltage on the red wire anyway.

Also, one caveat, because that relay energizes off the ignition module, its probably digital logic voltage levels, not 12v, so don't try to jumper the relay with 12v, that will probably fry the relay.

the good news is new replacement parts are still available, the bad news is its pretty expensive ($80-100)

the part number is 36100-MN5-000

Thanks.
Thats a very good explanation and im glad you mentioned about the voltage.
Ill wait to see if anyone can help with testing it before I commit to purchasing a new one.

 

[Andrew Shadow]

The fuel pump works when it is hot-wired. Has it been confirmed that it is inoperative under normal conditions, meaning do you know that the lack of fuel delivery is due to an inoperative fuel pump. A defective vacuum fuel shut-off valve is a common failure in the ST1100 fuel delivery system and results in an inoperative engine as well. I just thought that I would mention it as a possibility since it is a quick and simple check. If it has already been checked and/or bypassed then disregard.

 

[Buellboy]

The fuel pump works when it is hot-wired. Has it been confirmed that it is inoperative under normal conditions, meaning do you know that the lack of fuel delivery is due to an inoperative fuel pump. A defective vacuum fuel shut-off valve is a common failure in the ST1100 fuel delivery system and results in an inoperative engine as well. I just thought that I would mention it as a possibility since it is a quick and simple check. If it has already been checked and/or bypassed then disregard.

Evening,

The pump works when hot wired but I didnt try to start the bike to see if it runs llike normal.
The pump doesn't prime when ignition is turned on and can't hear it when trying to turn the engine over. I can get it to run with the choke on but as soon as I turn choke off or give it some throttle it dies, which seems strange?

Looks like someone has removed the fuel shut off valve.

Thanks

 

[DeanR]

I'll be paying attention to this, as I have the apparent same problem with my 91.

no power to fuel pump | ST1100 Related

Need to run my '91. It's been a year or two that it's been sitting. With no fuel tank (it's been empty and in the house) and drained carbs. Fuel pump is not starting with the key, runs fine when jumped. Wired connections all look ok. Where should I look?

www.st-owners.com

gravity fed fuel tank | Tools/Workshop/Garage

Boy has this project been a pain in the butt. All connections checked again. Air filter back on. No fuel cut valve. Previously removed. Opened hanging fuel tank valve, key on, pushed starter. It tried to start but only did so when given a bunch of throttle. Almost idled. Not quite. I think the...

www.st-owners.com

 

[Uncle Phil]

IIRC, that does look like the relay that I had to replace.

 

[dwalby]

The pump works when hot wired, and
The pump doesn't prime when ignition is turned on

I'm curious about this symptom from those who have had to troubleshoot this issue.

I'm gonna make a wild guess that when you turn the key on, but before you hit the starter button, the ICU has a short time-out period where it activates the fuel pump for a second or two. So, if that's missing, and the pump works when hot wired, the problem is either in the relay or in the wiring from the relay to the fuel pump.

So, if my assumption is correct, the next step is to disconnect the relay and put 12v on the wire going from the relay to the fuel pump hot lead (I think that's the red wire, but hopefully someone can confirm that). Then if the fuel pump runs in that mode, the relay is most likely the failed component in the path. The only other thing would be the ICU itself, and hopefully its not that.

 

[DeanR]

This was a while ago, and the bike has just been sitting in the garage since. I had swapped out the relay for another one, with no change.
Beyond that, electrical stuff is a mystery to me.

 

[Ron]

The fuel pump relay runs the pump for a short time when the key is turned on which means it is a special Honda only relay.

I'm not sure why it does that. It can't be for priming the carbs. If you still have the vacuum fuel valve, as Honda designed it, it doesn't open until there is a vacuum on the valve. A vacuum is not created until the motor turns over.

A temporary fix? You can "hot wire" the pump with a fused, keyed turned on circuit to run/ride the bike. The pump runs all the time the motor is running anyway.

 

[Uncle Phil]

I'm curious about this symptom from those who have had to troubleshoot this issue.

I'm gonna make a wild guess that when you turn the key on, but before you hit the starter button, the ICU has a short time-out period where it activates the fuel pump for a second or two. So, if that's missing, and the pump works when hot wired, the problem is either in the relay or in the wiring from the relay to the fuel pump.

So, if my assumption is correct, the next step is to disconnect the relay and put 12v on the wire going from the relay to the fuel pump hot lead (I think that's the red wire, but hopefully someone can confirm that). Then if the fuel pump runs in that mode, the relay is most likely the failed component in the path. The only other thing would be the ICU itself, and hopefully its not that.

Pretty close to what I remember.
The relay becomes 'flaky' and often mimics a failing fuel pump.