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Buell Forum » Old School Buell » Archive through May 23, 2016 » Fuel pump short cycling and bike won't start « Previous Next »

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Haaken
Posted on Sunday, May 15, 2016 - 01:59 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Fired the bike up for the first time in a few weeks and it was idling very poorly and wouldn't rev. I thought maybe it needed the ECU reset since i started it a few weeks back without the o2 sensor hooked up after i installed new header gaskets. Pulled the battery terminal and now the bike won't run at all...

Checked the plugs first and they were totally dry. I realized after that the fuel pump only turns on and cycles for a second. I checked all of the fuses and swapped the relays to no avail.

Any ideas?
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Two_seasons
Posted on Sunday, May 15, 2016 - 04:23 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Go back to the relay/fuse phenolic block, the black one, located under your seat.

While you are pressing the start button, rock your relays back and forth in the relay/fuse block and see if it will start. I just had the black/red wire pull out of the back of mine and my S2 would not start.

If that works, the wire connector lock is probably bent/broken on that wire.
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Haaken
Posted on Sunday, May 15, 2016 - 05:32 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

ill check it out. I have the subframe disassembled at the moment so its possible that is wobbled out as i had the bike running and the wires dangling. I took a multimeter and checked all of the connections though and everything looked good. Will double check though. When i went to take the ground wire off the battery, i had a distracted moment and started taking off the positive wire and ended up arcing my ratchet off of the head. Could that have blown the fuel pump?
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Haaken
Posted on Monday, May 16, 2016 - 01:37 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Rechecked all of the fuses, switched relays, etc. Still nothing . I pulled the connector to the fuel pump and checked the wires. No fraying or cut wires and the connectors looked good. I took a multimeter and checked the connections. I have a good ground, and the gray wire shows power going into the pump. Does anyone have any suggestion? This is driving me nuts and I don't know what else to check now.
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Natexlh1000
Posted on Monday, May 16, 2016 - 02:24 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

It may very well be the pump itself if you eliminated all of the other crap.

Cover the basics too like is the battery good and tight, stuff like that.
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Haaken
Posted on Monday, May 16, 2016 - 02:53 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I recheck the battery as I have taken it of several times in an effort to reset the ecu. Whats really odd is that the fuel pump comes on, but only momentarily. It is consistently about a second every time and doesn't make any odd noises. It's almost as if the ECU is not allowing it to prime itself.

Im really hoping that somehow when i hit my ratchet on the head briefly when taking off the positive terminal (i know i should have done the negative first, my girlfriend was talking to me and I thought i was pulling off the negative) that the small arc it produced didn't kill the fuel pump or something else.

What else controls the fuel pump besides the ECU? Are there any conditions that would stop the computer from allowing it to run?
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Haaken
Posted on Monday, May 16, 2016 - 03:28 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Did more digging and so far there are 4 wires going into the fuel pump. Yellow for low fuel indicator, black for ground, gray for what I believe is the ignition circuit, and there is a brown wire on the pump itself that feeds into what looks like a brownish wire (they are kid of faded). I am getting 12v from the gray ignition wire, and around 6v from the brownish wire. It would appear that I am getting the needed power to the pump.

I tried forcing the pump on manually by using some new stripped wires as make shift connectors, but i couldn't get the pump to do ANYTHING that way despite the fact that when properly plugged in it at least does a partial priming cycle. Feeling a little stuck now.
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Hootowl
Posted on Monday, May 16, 2016 - 03:36 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

It is supposed to come one briefly when you first turn the ignition on. Does it run when you try to start the bike? If the bike runs, even poorly, the pump has to be running. Check your fuel pressure?
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Haaken
Posted on Monday, May 16, 2016 - 04:07 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I know that the pump needs to come on briefly. I know exactly what it should sounds like and how long it should kick on for. Right now it only comes on for a brief moment when either cycling the ignition or kill switch. The bike will turn over but will not fire at all. I pulled the plugs and they are completely dry after trying to start. I would expect my fuel pressure to be zero at the moment since the fuel pump is clearly not running beyond a brief moment when cycling the ignition. Is there something else that controls when and how long the pump runs for? I want to run ECMspy and run a diagnostic, but I only have a mac and can't get it to work on it.
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Hootowl
Posted on Monday, May 16, 2016 - 04:37 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Ah. Not running. You confused me with your first post. "Fired the bike up for the first time in a few weeks and it was idling very poorly and wouldn't rev"

The ECM definitely controls the pump, but there are several interlocks, as it's tied to the ignition. The stop/run switch is one. Probably the neutral and clutch switches, and probably the side stand interlock switch too.

Since it comes on briefly, it's unlikely to be any of those. ECMs are pretty durable, but anything can fail. Do you have one you can swap in to see if it changes the behavior of the fuel pump? Know any Buellers in FL that are close that might be able to loan you one? Check BRAN for someone close? I gave away my stock ECM...
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Hootowl
Posted on Monday, May 16, 2016 - 04:42 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

If you've got the pump out, try hooking it up to the harness and cycling the ignition, and just when it shuts off (prematurely) give the pump body a little tap. Maybe it's going bad, and won't turn after the first jolt of juice.
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Haaken
Posted on Monday, May 16, 2016 - 05:11 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Unfortunately I don't know anyone else with a buell here. It's just so odd since literally the only thing that changed between when the bike was running and the pump functioning, and now is when i accidentally started taking off the positive terminal first and arced my ratchet off of the cylinder head...

What a headache. Looks like this project is getting shelved yet again I don't have any money at the moment to get a new fuel pump or ecu as i just lost my job last week. Was hoping to just get this project wrapped up so it was one less thing to worry about and hopefully blow off some stress but looks like it has turned into the opposite.
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Two_seasons
Posted on Monday, May 16, 2016 - 09:03 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Check all the grounds for clean and tight, both ends.

Grounds are located at...
o Voltage Regulator-Black wire
o Ground Strap in front of the rear tire at the swingarm.
o Above the Battery in your circuit breaker. Make sure all the connections are clean and tight
o There is another one around the steering head somewhere, maybe some one here can be more specific for you.

I hope you find the problem.
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Haaken
Posted on Monday, May 16, 2016 - 09:46 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

If i could confirm the proper voltages coming into the pump from both the grey and brown wires, that might confirm if there is a problem beyond the pump, but i can't find any specifics anywhere unfortunately. From what i can tell at least, the negative wire going into the fuel pump is properly grounded.
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Haaken
Posted on Tuesday, May 17, 2016 - 07:06 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Feeling like a bit of a , but with as little information out there on our bikes i goes i can't be too annoyed...Turns out it was the Bank Angle Sensor causing the pump not to run completely. I knew the ECU was giving it a no go signal, but I couldn't figure out what exactly was causing it. Did a ton of reading last night and found on a harley forum someone describing bypassing the sensor and that sparked the thought. Just checked it the morning and the fuel pump fully cycles. Will try starting it later when it isn't 7:00 in the morning and pissing my neighbors off.
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Firemanjim
Posted on Tuesday, May 17, 2016 - 01:45 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Beat me to it-- was going to suggest BAS
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Haaken
Posted on Tuesday, May 17, 2016 - 03:03 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I am so glad it turned out to be something so simple. In all of my searching this was never mentioned. I love this bike and have had it for around 5 years now, but there is so little information out there on the older bulls that it makes things hard sometimes. Having a newer bike as well, its something I have been taking for granted lately apparently...It's all good though. Makes me a better problem solver i suppose
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