Fuel pump problem?

[Mark2864]

Hey gang,

I think my fuel pump stopped working/dried out from being out of the old tank for too long while I was replacing the old tank with a “new” one. (Is that a thing?) Do I need to prime the fuel system? How do I test the fuel pump? Where do you order a new pump from? Anyway, I’m not hearing the fuel pump making noise. I checked fuses, but haven’t checked the fuel relay yet.

I think my wiring job is done from doing the alternator upgrade. Went to test it, and I’m not getting fuel now. It’s been apart for a while …

Any suggestions appreciated!

 

[Uncle Phil]

Any pressure when the hot wire is connected?
If you are 'brave' you can stick it in a bucket of gas, ground it and power it up and see if it pumps.
Fuel cutoff removed?
Could also be the fuel pump relay.

 

[Mark2864]

Any pressure when the hot wire is connected?
If you are 'brave' you can stick it in a bucket of gas, ground it and power it up and see if it pumps.
Fuel cutoff removed?
Could also be the fuel pump relay.

I think I’ll check to see if I’m getting power from the bike to the fuel pump wires and then try 12v directly to the pump from a battery and see what happens. I have a feeling that the fuel pump “seized” from being out of the tank for so long, but I’m not positive. Might have to rebuild/replace the fuel pump.

 

[SMSW]

If you are 'brave' you can stick it in a bucket of gas, ground it and power it up and see if it pumps.

I'd suggest you use something less flammable, like mineral spirits (paint thinner). I've lost enough friends in the last couple of years.

IIRC, @Uncle Phil has said aftermarket fuel pumps can be had for less than $60. If you like Honda, I think older Civic fuel pumps can be used. (try doing a search for threads w/ Fuel Pump in the search box.). You should be able to just take the fuel pump in your hand, put the wires across a battery for a second or two and hear it spin. Or not.

 

[Al st1100]

no need to stick it in a bucket. Use a voltmeter or test light on the wires to the fuel pump key on should be battery voltage for the first few seconds. If you have the pump out on the bench hot wire it to 12 volts. Make connections solid on the pump to keep sparks away from any fumes near or at the pump. If you hear a nice clean buzz the pump is working. However these pumps have internal brushes that can stick and removing the pump may have jared the brushes loose. IMO if the power and ground are good at the bikes pump connectors I would replace the pump.

 

[Mark2864]

Good info

no need to stick it in a bucket. Use a voltmeter or test light on the wires to the fuel pump key on should be battery voltage for the first few seconds. If you have the pump out on the bench hot wire it to 12 volts. Make connections solid on the pump to keep sparks away from any fumes near or at the pump. If you hear a nice clean buzz the pump is working. However these pumps have internal brushes that can stick and removing the pump may have jared the brushes loose. IMO if the power and ground are good at the bikes pump connectors I would replace the pump.

Good info, thanks!

 

[bdalameda]

I have seen quite a few ST1100 fuel pumps fail intermittently. I had mine fail this way. Ran fine and then just quit - sat a while and it started to operated normally again sometimes for weeks and the it would quit again. I remember taking it out and it worked fine on the bench and then I put it in and it failed again almost immediately.

 

[Mark2864]

Thanks. I just ordered a couple of spares (eBay and Quantum Fuel Systems) to have just in case. I have no idea how old the current pump is, and I have a feeling that it “dried out” from being out of the tank for a while. I’ll still check to make sure I’m getting 12v at the wires, and put 12v directly to the pump to see if the old one works, but I have a feeling that I wrecked it by letting it sit outside the tank

 

[SMSW]

Thanks. I just ordered a couple of spares (eBay and Quantum Fuel Systems) to have just in case.

A number of Amazon fuel pumps come w/ fuel lines that get soft and fail when immersed in gas in the fuel tank. I have no idea about the ones you ordered, but be sure to use fuel line designed for total immersion.

 

[Mark2864]

Yes, I heard about that, thanks! 30R10 fuel hose is the stuff I’ll need. Might order some just in case. The lines are pretty stiff

 

[Uncle Phil]

Be aware that some aftermarket pumps say they are speced for a ST1100 but they put out way too much pressure.
Quantum is one of those and I have had the 'discussion' with them.
The simple way to know this is if the ST1100 will start when cold without the choke (technically the fuel enricher).