Another Uncle Phil Interesting Running Mystery

Well at least it appears to be a 'hard' failure this time - which is easier to diagnose.
I checked the 'fire' at all four plugs and they are firing.
I checked the voltage to the fuel pump and it is a consistent 12-14 volt range.
When I pulled the fuel line loose from the tank and turned the key on the pump did not pump anything.
It should be squirting out a stream of fuel.
So back to pulling the 'brand new' fuel pump out of the tank to see what is up with that.
Now I'm thinking an issue with the terminals on the fuel pump stalk or a wire loose on the fuel pump.
At least at this point I know a bunch of stuff that probably ain't the problem. ;)
 
I've noticed that there have been quite a few fuel pump issues over the last couple of years with newer fuel pumps. Honda has had recalls on both the Africa Twin and recently with newer Goldwings(Denso pumps). The problems are with the impeller materials deforming and swelling over time which locks up the pumps. Other pump manufacturers may have issues as well.
 
Well, what an 'interesting' afternoon.

I couldn't get any voltage reading with my multimeter which seemed strange.
So when I put it to the battery terminals I still got no reading.
Turns out the ground lead was broken internally.
Ah, so that's the problem ... Nope!

I pulled the new fuel pump out of the tank and saw that the ground wire connection looked really 'iffy' so I fixed it and reinstalled.
Ah, so that's the problem ... Nope!

Then I couldn't get a voltage reading at the positive terminal on top of the tank.
As I removed the wires to pull the pump again to measure the voltage at the pump end, lo and behold the positive connector on top fell off the wire.
I fixed it and reattached it before I pulled the pump again.
Ah, so that's the problem (probably part of it) ... Nope!

It turns out that the new pump I installed to replace the one that was in there was deader than a hammer.
I replaced it with another new one (nice to have spares on hand! ;)) and reinstalled the stalk again.
Ah, that seems to be the final problem.
So the 'original' problem was probably the bad connector and a dodgy fuel relay.
It appears to have been a fuel issue all along and not a fire issue.

Some days this stuff really makes your head hurt! :biggrin:
We'll see if I have really fixed when I get a chance to take her out for long test ride this week.
One thing is for sure - if you have 4 bikes on the road and do very many miles, you will run into just about every issue you could sooner or later.
 
Uncle Phil said:
..... dodgy fuel relay.......
Click to expand...

Interesting indeed!

When you were jump testing the relay and noticed the drop, did you by any chance also check the input on the coil side of the relay at the same time, to make sure nothing funny was happening there either?
 
MidLife said:
Interesting indeed!

When you were jump testing the relay and noticed the drop, did you by any chance also check the input on the coil side of the relay at the same time, to make sure nothing funny was happening there either?
Click to expand...
Nope, I was just measuring the voltage at the input into the fuel pump.
I've had one fail before exhibiting the same symptoms after I replaced the fuel pump thinking that was the problem.
The effects are basically the same whether the fuel pump is dying or the relay is dying - gas starvation and no power at full throttle.
 
Uncle Phil said:
Nope, I was just measuring the voltage at the input into the fuel pump.
I've had one fail before exhibiting the same symptoms after I replaced the fuel pump thinking that was the problem.
The effects are basically the same whether the fuel pump is dying or the relay is dying - gas starvation and no power at full throttle.
Click to expand...

What I meant....sometimes a relay can appear to be failing.....when in fact it is due to intermittent triggering current...
 
That connection is a 'standard' (of sorts) Hitachi click in place up under the left upper fairing and the wires looked good.
They are never 'touched' or moved due to location unless you are replacing the relay.
Any way to test a relay once it is removed to determine if it is indeed faulty?
 
Uncle Phil said:
That connection is a 'standard' (of sorts) Hitachi click in place up under the left upper fairing and the wires looked good.
They are never 'touched' or moved due to location unless you are replacing the relay.
Any way to test a relay once it is removed to determine if it is indeed faulty?
Click to expand...

Easy to test at your advanced skill level!

However...a relay that appears to be "good" at room conditions doesn't always work at higher temp.......

www.thedrive.com

How To Test A Relay

If something goes sideways with your vehicle’s electrical system, there’s a good chance a relay is to blame.
www.thedrive.com www.thedrive.com

The switching wires to the coil side may be looking good, but it is not always a testament of what is flowing through them.

Your relay may be switching off intermittently because it is going bad (not uncommon for fuel pump relays and your most likely culprit), but the interruption could also come from something happening on the switching side and causing the coil to be briefly de-energized. Just wondering as it seems it is not the first time you have the issue.

Interesting that the first guy who commented on the article above precisely had a relay that was acting up....but worked fine after clean up. That cannot be completely excluded.
 
Uncle Phil said:
Any way to test a relay once it is removed to determine if it is indeed faulty?
Click to expand...
It is easy to test a relay as the article linked to above illustrates. However, using an OHM meter can result in misleading results. It can show continuity giving the impression that the relay is good. Even though the contact points are closing the relay still may be incapable of flowing sufficient current to power the load that is on it due to burned/pitted contact points. Not optimal, but a better choice is a test light as it does impart at least a small load on the relay. If the test light does not burn as brightly as it does when connected directly to a battery there is cause for suspicion. Often a defective relay that shows continuity with an ohmmeter will have damaged contact points due to arcing.

Given the age of the ST1100 they are most certainly all mechanical relays with points. I always pull the cover off and inspect the contact points when I think a problem may be due to a relay, and often find burned contact points. The points can be filed down as a temporary repair but the relay should be replaced in the near future. Once the plating on the contact points has been burned off the pitting damage caused by normal arcing will return more quickly.
 
Uncle Phil said:
Any way to test a relay once it is removed to determine if it is indeed faulty?
Click to expand...
Not that I know of. Sure, you can test a relay by removing it from the circuit, powering the coil, etc...but if it is an esoteric intermittent failure it is probably better to just change the relay unless it is a special expensive one.

Like everything else, there are good brands and notso good relay brands. The better ones are good for thousands of cycles (some 100,000) and most are cheap. I'd refer you to the easternbeaver website to read what the owner has to say about relays. He may or may not be an expert, but he sells quality brands.

Does the 1100's fuel tank have a cover like that on the 1300's lower tank? What I am talking about is a complete assembly of pipes, pump, filter, etc mounted under the cover. The reason I am asking is could you have simply swapped the whole shebang on your bike or is the pump entirely separate from the cover/wiring, etc.?

Glad you finally figured this one out. I really don't know what an 'eggspert' would have done differently to solve this problem. How could he have induced the failure in the shop after each 'fix'? Maybe a vibrating bike rotisserie? Get one of those 'ride the bull' machines from a western bar, remove the 'bull' and install the ST1100, fix something and then turn the machine on...?
 
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