Consistent and inconsistently bike shutting off

[jakgieger]

Pump doesn't run until you hit the start button.  If you had the hose off of the rail, and pushed the start button, and did not have a stream of gas...you have a problem (bad pump, bad voltage to pump, OR restriction in the fuse line or filter).  All three are easy to check.  You need to become familiar with removal of your gas lid in order to ascertain various maladies.  While the lid is off it would be a good idea to lube the mechanism and remove the door flapper in order to gain maximum capacity and viewing privileges.  You might even discover undisclosed contraband in your tank!    BTW, this fuel injection system is by far more simple/reliable than a carb.  Ever heard of a quadrajet???

[KJM00]

Never a quadrajet heh.  But yeah I opened up the top of my tank and peered through, that's when I was listening for the Fuel Pump.  No debris in the tank at all...till i opened it and a few VERY tiny paint chips fell in.  I put my ear to the opening of the tank with the entire view there after looking in at clean fuel/fuel injector/fuel filter and all looked pristine but absolutely ZILCH for sound coming from my pump when turning my ignition and pressing the start button, no WRRR of it kicking over.  Mind you I checked the fuse, perfect condition, Fuel tank plug has been cleaned, and seated 100% properly, and Connection to ECM is perfectly snug.

[wally.fisher]

 Is the big plug under the seat fully seated???


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[KJM00]

I believe you're talking about the ECM being properly plugged in.  And yes, as snug as snug can be.

[Laitch]

The troubleshooting chart shows to more areas to check before the pump is pulled. If those steps uncover anything. After that, I'd drain the tank and pull the pump to check its wires for continuity and the pump for operation.

[KJM00]

I gotta get my hands on a multimeter and start some electrical checks..  :musicboohoo:

[Laitch]

I gotta get my hands on a multimeter and start some electrical checks..  :musicboohoo:

You could remove the pump now and check it for function until you have a multimeter. It'll keep your hands busy. :giggles

[jakgieger]

You could remove the pump now and check it for function until you have a multimeter. It'll keep your hands busy. :giggles

TAKE LAITCH'S ADVICE,  check pump (external) and verify no restrictions in filters...

[KJM00]

So here's where were at, I pulled the pump and tested the pump and it works perfectly. (Bittersweet good thing) And replaced my fuel filter well I was at it just because. My tank was very clean. I had my brother who is an electrician in training check my four pin female tank connector and fuel pump connectors the connectors are perfect to the fuel pump but he said two of the female four pin seemed to be unresponsive so he suspected that there was a possible electrical line pinch or that one of the wires on the female side is shorted/damaged.  Either this evening or tomorrow I'm going to pull my tank so that we can make sure there's no contact pinch and to solve my electrical problems I hope. Any extra suggestions from you guys?

[Laitch]

It seems to me you're on the right track. Keep going.

[KJM00]

Okay, so we checked all of the Relays, which all seemed to be working perfectly.  Then proceeded to check the connection to the Ignition box, which we removed and reseated properly.  At this point the multimeter verified that all connections to the relay box, female fuel tank connector, and male fuel tank connector all seemed perfect, we couldn't find a single problem wrong.   So at this point I just said F it, so we connected the tank to the electrical connector well off of the bike and powered up the bike and the pump was making sound in an empty gas tank, it seemed like a miracle.  Then we plugged the tank back in, put fuel in the tank, and attempted to start the bike and the Fuel pump no longer made any sound at all...  So I have to assume it's a failing sensor...Since we couldn't find any issue with the female/male side of the jack, the only alternative is possibly that the plug itself isnt always meeting a full contact?(The fuel hose that delivers to the rail, well off the rail, didnt drip well full or well there was only a tiny in the tank when the pump was actually running)  I don't honestly know, but I'm beginning to lose patience with the situation, and it's feeling a bit hopeless, I really didn't wanna take it to a specialist, but I feel that's the direction it's going. :dunno

[Laitch]

. . . so we connected the tank to the electrical connector well off of the bike and powered up the bike and the pump was making sound in an empty gas tank, it seemed like a miracle.  Then we plugged the tank back in, put fuel in the tank, and attempted to start the bike and the Fuel pump no longer made any sound at all...  So I have to assume it's a failing sensor...Since we couldn't find any issue with the female/male side of the jack, the only alternative is possibly that the plug itself isnt always meeting a full contact?

It's best not to assume anything. Which "sensor" is failing and how exactly is it failing? Have you determined that wires from the fuel sensor to the pump have continuity? You tested the pump and have stated it pumped. Did you try it on the bench with fuel?  If you determine the plug isn't making full contact or that sockets on the female side are faulty, you can replace both sides with a 4-pin trailer plug or other assembly at reasonable cost as others have done.

Patience is what it takes to solve these things; that's for certain.

[KJM00]

I'm going to look into the idea here shortly of replacing the four pin connector as you suggested.  The Fuel Sensor is the only thing i was talking about, as it's what provides the power channel to the Fuel Pump. And the connection to the pump did have continuity.

[Elipten]

I found the wires from the fuel sensor to the pump severely degraded in my tank.  I bought new wires that can be immersed   in fuel and replaced them.  Be careful when unsolder  and soldering not to heat too much or too long and destroy the plastic that the pins sit in and seal the tank.


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[KJM00]

I actually haven't checked the connection DIRECTLY to the sensor, but the wires to the pump itself looked pretty wonderful.  I'll give that a go, before entirely throwing in the towel.  Thanks for the suggestion. 

[Martin]

I accept no responsibility if you blow yourself up, but for proof you could carefully route new wires from the pump out through the filler neck to the four pin connector. Connect the new wires to the pump first and then to the four pin connector. We do not want any sparks occurring in the tank. :nono
Regards Martin.

[KJM00]

That's a solid idea, a dangerous idea, but it's solid still.  :giggles

[Elipten]

It is a logical process of checking each possible connection issue.  A tech will do no better.  The members here have a vast amount of experience.

Get deoxit and clean every contact.  These bikes are 20-30 years old and often unloved for most of them years. 


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[KJM00]

I don't doubt the members as much as my own technical apt-ness, but I'll try to maintain a positive outlook and tread on.

[The Mighty Gryphon]

Don't begrudge the time spent working on your bike.  You are becoming intimately familiar with it in a way that simply riding it doesn't allow.  With older machines like these you can never know too much about them.

Don't worry, the riding season has barely started and you'll get a lot of riding in when you get it sorted.

[Martin]

These bikes would have to be on of the most bullet proof bikes out. Key to low maintenance is keeping the electrical connectors clean. I cleaned mine on the advice of a mate an ex BMW mechanic when I first got mine nearly twenty years ago. I also use dielectric grease as I believe it keeps out water and air which leads to corrosion. Besides batteries and tyres I've three electrical breakdowns all my fault, two were the temperature sender connection limped home. I failed to clean it properly as it was too hard to get to, learnt my lesson. Third loose connector nut on my isolator switch connector due to lack of spring washer. Once you sort it you should just have to maintain it.
Regards Martin.

[KJM00]

My dad owned an RT about 15 years ago, and that's all he said/I hear: They're indestructable! They'll never let you down, but I've been nursing my poor new to me K-bike for two months straight,(Battery, forks/seals, swapping brake fluid, cleaning nooks and crannies, oil/filter, fuel filter, air filter, new heated grips((that one is more of a luxury)), repairing broken odometer, etc etc etc) All i wanna do is ride her very far distances.     She looked to be in good shape when i purchased her, but I'm taking care of the neglect of the previous owner, ontop of my newfound problem(s).

[Elipten]

Yep you have to correct the original design flaws from BMW, old age, lack of service and the service BMW never dreamed of not expecting the bikes to last this long.

Once you sort it,  it will run so well and so long that the rider wears out, not the bike.


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[jakgieger]

Keep working...YOU WILL BE REWARDED with a machine that will go wherever you want to.  My first bike (R60/5) came in a box of parts and my current K came out of a barn (with our little furry wire eating friends, f-ing mice) after sitting for 10+ years.  The current problem may seem insurmountable, but it isn't.  At points like this, it may help to pull out Zen and Art of MM .  The machine you are working on here is YOU!  Step back (beer is a common aid at this point) and assess your perspective, approach, attitude, fears of screwing up, mechanical assumptions, etc.  If at this point you would like to punch me, you are in the bad place.  Re-Reassess and start again.  Laitch gave the advice on the flow chart.  It is there for a reason.  Methodology is a great aid when confronting the mysteries of life and motorcycle maintenance. 

Years ago, I had a noise in a truck that went away when I pushed the clutch in.  I immediately ASSumed  :nono I had a clutch problem.  Worked for a week pulling motor and changing clutch assembly.  Upon reassembly, I STILL HAD THE NOISE!  It turned out to be an alternator bearing  :eek: .

[The Mighty Gryphon]

If I've said it once, I've said it a hundred times.  Service and maintenance on your bike, or any machine for that matter, is just like foreplay.

The more you do and the better you do it, the better the ride will be.