Yet another fuel pump issue .... sorry - long..

Odie1

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Ok..... I will try and be brief, but have a lot of info....but I will get to my questions!

I have a 96, ST1100 standard, just under 60K miles, fuel cut-off diaphragm removed....

About a year ago I had what I thought was the classic sign of a fuel pump beginning to fail... After running many miles at highway speed, made
a brief stop, did NOT add fuel (tank was close to empty... light just starting to flicker), and after getting back on the road about a mile,
the bike died....as if it had no fuel. Got a lift home (not too far - thankfully) and a day later when I checked, the fuel pump spit out fuel
and the bike ran just fine. Since that time, I have never let the tank get very far below half full, and have never had another issue. I have
also not run extended periods at what I would call highway speeds.

After this experience, I decided I really didn't want to be stranded beside the road, again, so I purchased and installed an external Facet
fuel pump and mounted it where the fuel cut-off diaphragm used to be. I had extra hoses in place where I could easily remove and replug two
hose ends, disconnect the wires to the factory pump and connect the Facet wiring to them, and be on my way (..as I have seen many others do on
this site!... that's where I got the idea...)...in theory anyway.....

I did take a few rides using the Facet pump... for an hour or so each....and had no issues, so I thought all was well. NOW - I do not believe
I ever did a true test where I started the bike using the original fuel pump.... unplugging the wiring so that the carbs would all run dry, and
THEN connecting up the Facet, and trying to restart.... more on that later....

So, Monday, I got a day off work, and headed for some new roads in SW Missouri and NW Arkansas. All I can saw is...WOW!... If you have never
been there - you need to go. I rode just a shade under 500 miles, lots of twists and turns, several stops, just a wonderful day.

In the middle of the ride, I took about a 40 mile stretch on interstate.... running 70+ MPH, while the fuel did drop well below half, and at
the end of that stint, I had gone nearly 225 miles on that tank, I pulled off and got fuel...no issues. On the last leg of the trip, just
about home, I decided to take a toll road and again rode about 40 miles at highway speeds - 70+ - this time the tank had more fuel in it... had
only traveled 100 miles since the last fuel stop... and just at the end of the toll road, that sickening feeling... bike seems to be running
rough.... roll on the throttle and nothing.... bummer...

Coast to the side of the road and think to myself, "I am prepared for this, bring it on!". Thankfully, the Lord once again provided just about
the ideal safe spot to break down in. So, off comes the seat and faux tank cover, and sure enough... fuel filter is bone dry. Thinking I knew
what the issue was, I did not take a second to see if I could hear the factory fuel pump cycle on...I should have.. I then replumbed the
hoses, connect the wires to Facet, and start flipping the run switch off and on to cycle the pump...I can definitely hear it running. I think
I see some fuel come up in to the filter, its not clear but white plastic, so I am not positive. After a bit of this, I turn the motor over a
few times and she fires... woohoo!. Running kind of rough, but I figure its just that all the float bowls must not be totally full. Shut it
off and button everything back up and put all the tools away... gear back on and away I go....

For about half a mile....

Dies again - same symptoms. Pull over... strip off seat and tank cover, and again - fuel filter bone dry..??? Fuel pump runs when key or
switch is toggled. I disconnected the output of the pump, but there is nothing coming out...and when I say the pump is running, it runs for a
second or two at a time, as I cycle the on off switch.... I really cannot remember if while I had the output disconnected I tried turning the
motor over for several seconds... thus keeping the fuel pump running... Also... I DID remove the gas cap in case there was some horrific
pressure build up. No woosh when I took it off, and it made no differnce to the fuel pump.

Its starting to get dark (note to self - ADD A FLASHLIGHT TO THE EMERGENCY BREAKDOWN KIT!) so I make the call.... My son gets the truck and
will be here in 20 - 25 minutes.

As I wait, I play.... now I know this is REALLY subjective, but I tried to draw fuel from the tank using myself as the pump.... using lips
only... I have heard too may horror stories of people inhaling gasoline. I was able to draw out some fuel, but it felt like I was trying to
drink a really thick milkshake. This was with no filter, pump ect... only a short piece of rubber hose connected to the metal tube from the
tank. And again - the gas cap was off.

So, at home the next day, again I play. Remove output of Facet...cycle engine switch, hear pump run... nothing. I removed the hose from fuel
tank inlet, add a short piece of hose, and drop it into a 5 gallon gas can.... full. Toggle the engine switch.... nothing?!?! NOW - again in
all fairness... I don't THINK I ever turned the engine over with the starter, keeping the fuel pump running for more than a couple of seconds
with the input hose in the can of gas..

I re-connect a hose to the fuel tank, re-connect the wiring to the internal fuel pump, turn the key... and as expected, out comes fuel. Re-
plumb all the connections, and the bike fires up runs like a champ. Factory fuel pump has cooled off and acting as normal.

So, I play with the Facet... with the input still in the gas can, I jump the leads to the battery.... and after a few seconds, it's pumping gas
all over the place.... well - at least into the catch bucket I have....

Also, AFTER the factory fuel pump had cycled and pumped gas, I played again and used myself as the pump. And it seems that now the fuel is
much easier to draw out of the tank. Can I be sure, or can I quantify it?... no.... but definitely SEEMS to be freer flowing... I wish I had tried BEFORE
cycling the factory pump.

OK - so now I have some testing to do, but was also wondering if anyone might know some of the answers up front.

1. Has anyone ever had a fuel pump failure where it has "locked" up and prevented fuel from (easily) being drawn from the tank ? I do believe I
will be pulling the pump and looking for obstructions as another check.

2. Regarding the Facet pump... with my extra "plumbing" in place, I have nearly two feet of hose from the input of the pump to the tank. Is it
possible that with the way the ST's fuel cutoff relay works - cycling the pump only a couple of seconds at a time BEFORE the engine starts -
that it might never draw fuel into the pump, since the fuel might drain back down the hose each time the pump shuts off? I know the Facet has
some type of "back-flow prevention" so you cant leave the pump in-line when not in use, but would that keep fuel from flowing back out the
input?. I almost discount this since while I had the pump wired up and in-line, I ran down the road half a mile or so... so, nearly a minute
maybe? I would also think you could just turn the engine over for 30 seconds or so and that SHOULD be enough time to get fuel to the carbs...


And as always - please point out if I am missing the forest for the trees.... I would really like to get this sorted out. Makes me a little
more worrisome when heading out on the road....

Odie1
 
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Odie1

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1996 ST1100
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I got a little wordy there........OK - maybe a LOT wordy... sorry.

I guess my base question I have is this.... When the factory fuel pumps begin to show signs of failure... typically when they get hot they stop pumping fuel.... will that stop or severely restrict the flow of fuel through it... weather or not it is trying to pump fuel?

I know from testing in the past that you can draw fuel through a cool "inert" pump (one not connected to power, but sitting in the tank) using an external pump, but when I had one fail out on the road, the external pump was unable to draw fuel through the in-tank unit.

Thoughts? I still plan on pulling the pump from the tank as soon as I get a chance to see if I possibly have something that could be temporarily blocking the intake.

Odie1
 

ST1100Y

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I know from testing in the past that you can draw fuel through a cool "inert" pump (one not connected to power, but sitting in the tank) using an external pump, but when I had one fail out on the road, the external pump was unable to draw fuel through the in-tank unit.
IIRC does the OEM fuel pump have an impeller and a check-valve (preventing back-flow)...
IIRC-2 will the OEM pump seize due corrosion on the rotor/armature (water contaminated fuel and that...)

With a narrow gap between impeller and pump housing, plus a given motor seizure, it seems likely that an aux pump will starve/not being able to suck sufficient amounts through the OEM device...

Edit: found some write up and pics:
http://www.st-riders.net/index.php?topic=7954.0
 
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Odie1

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1996 ST1100
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Had a chance to do a little "testing" last night. Of course, now 3 days later, the factory fuel pump has cooled off and seems to be working normally..assuming that is even the issue....

Started and ran the bike a few minutes using the factory pump, then disconnected power to it. In a couple of minutes the bike sputtered a bit and died, and would not re-fire...as expected. Then plumbed in the Facet unit and connected it to power. Using the on/off toggle switch, after three or four "cycles", I see gas being pumped into the filter (good, bright lighting... unlike beside the road as dark approaches). Hit the starter and after a couple of revolutions, it starts right up... somewhat ratty for a few seconds, but again I figure the carb bowls aren't completely full, and after 10 - 15 seconds, it runs smooth as silk. So that answers the question if the Facet fuel pump can pump fuel up from the tank cycling off and on a couple of seconds at a time.

Wondering if maybe there was something in the tank restricting the fuel flow, (and honestly - even after reading many posts here, and seeing pictures - not really understanding the fuel pump setup in the tank) I pulled the pump from the tank. Everything looked clean as could be.... and I now have a better understanding of how things are connected.

So, without dis-assembling the fuel pump like in the link above (Thank you ST1100Y!), I am going to make an assumption that when the factory pump overheats and fails, it does in someway severely restrict the flow of fuel through it.... at least while its still "hot".... not so much once it cools down....

So, with a pretty good idea that I have a fuel pump on its last legs, I think I will simply use the Facet pump as the main source, knowing (hoping?) the factory pump will work for a while if needed to get back to civilization.

And in thinking about replacing the "in tank" pump, anyone ever try one of these ? http://www.highflowfuel.com/i-13868228-new-intank-fuel-pump-honda-st1100-replaces-honda-16700-mt3-010-1990-2002.html?gclid=CLfluJbqo8gCFUGXvQoddTwJjA

Any thoughts ?

Odie1
 

ST1100Y

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You can probably utilize any GL1500 after-market replacement pump I've seen for under $60,- US...
 

Bigmak96

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Read the thread specific to the pump, for other replacement options.
 

John OoSTerhuis

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Interesting, hadn't seen that option before. I'm also interested in anyone's experience with this one.


"SKU: HFP-360STThe HFP-360ST replaces the intank fuel pump on 1990-2003 Honda ST1100 motorcycles, and includes a submersible corrugated fuel flex hose and new strainer to do the job correctly. It replaces Honda part # 16700-MT3-010 (Honda motorcycle code 4316162)."
 
Joined
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Interesting, hadn't seen that option before. I'm also interested in anyone's experience with this one.


"SKU: HFP-360STThe HFP-360ST replaces the intank fuel pump on 1990-2003 Honda ST1100 motorcycles, and includes a submersible corrugated fuel flex hose and new strainer to do the job correctly. It replaces Honda part # 16700-MT3-010 (Honda motorcycle code 4316162)."
This one has shown up on Ebay several times at $49.95. I am also interested in any comments from actual users...looking for a workable spare.
 
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look in fuel pump, old threads, there are many pumps (aftermarket) but the oe pump has a pressure regulator and check valve built into the upper part of the fuel pump which can and in my opinion should be used. The one that I used , looks just like hi flow, come off o 93 Honda puelude with carbs, low pressure pump
 
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