1996 R1100RT Won't Stay Running

[bcsugarbush]

I have recently joined MOA in an attempt to help my 1996 R1100RT. A few years ago I had to bring it home from the road on a trailer (after about 2 miles). Got it home and it ran well - took it out again and trailered it back again (less than 2 miles). Subsequent testing and it is running shorter and shorter. Research at the time showed many speaking of ailing fuel lines so I pulled the tank and removed the pump assembly. Nothing catastrophic, but the pump sock was destroyed and there was enough foreign debris to make me believe the pump could be fouling on debris that would fall back out of the inlet when you shut the machine down, yet get sucked back up with the next key cycle and the pump would seize again after a short period. And so on and so-forth. It fit the behavior as it seemed to be random in the duration the machine would run before dieing!

Anyway - new aftermarket pump (Quantum Fuel) and filter installed, no solution to the problem. I am expecting I have an electrical problem but do not have machine schematics or adequate system architectural understanding to dig in.

Suggestions much appreciated?

(I live in MN - the season is short so gotta-geet-er-done!)

 

[20774]

Welcome to the forum! The '96 R1100RT actually falls in the category of an Oilhead so I will move this to the other forum to get a better set of eyeballs on your question. That should help out!!

 

[gsaddict]

I have recently joined MOA in an attempt to help my 1996 R1100RT. A few years ago I had to bring it home from the road on a trailer (after about 2 miles). Got it home and it ran well - took it out again and trailered it back again (less than 2 miles). Subsequent testing and it is running shorter and shorter. Research at the time showed many speaking of ailing fuel lines so I pulled the tank and removed the pump assembly. Nothing catastrophic, but the pump sock was destroyed and there was enough foreign debris to make me believe the pump could be fouling on debris that would fall back out of the inlet when you shut the machine down, yet get sucked back up with the next key cycle and the pump would seize again after a short period. And so on and so-forth. It fit the behavior as it seemed to be random in the duration the machine would run before dieing!

Anyway - new aftermarket pump (Quantum Fuel) and filter installed, no solution to the problem. I am expecting I have an electrical problem but do not have machine schematics or adequate system architectural understanding to dig in.

Suggestions much appreciated?

(I live in MN - the season is short so gotta-geet-er-done!)

Mileage? Are you on the original hall sensor?
They typically exhibit the symptoms you have when the wiring is failing.
Does the bike quit instantly when it reaches a certain temperature and restart when cooled?

 

[m_stock10506]

GSAddict is pointing you towards two possible problems with the questions he has posed - or maybe others. The Hall Effect Sensor (HES) plate, if still original has wiring inside the plate's harness that has dried out and is crumbling into dust leaving bare wires exposed. It has to be either rewired or replaced. GSAddict is himself a great source for rewiring the plate with new heat resistant wiring. The ignition coil, located just under the front of the fuel tank. I have helped a couple of friends with 1100RTs that would run for a short while and then quit, and my own RT did the same to me. Replacing the ignition coil fixed the problem.

Please respond to GSAddicts questions first, and then he and others will try to help you.

 

[paul_f]

I had a similar problem with a faulty side stand switch.

 

[bcsugarbush]

All -
Thanks for the great insights. Given the holiday weekend coming up, I am more interested in having the top two or three candidates in my hands to hang in hopes of a quick resolution. I am also interested in having resolved the next two or three things that may be marginal in advance of having to trailer home from a vacation gone awry.

That said - here is what I have heard:
1) Rewire hall plate or purchase new
2) Coil replace
3) Intermittent side stand switch (which I think is already bypassed)

What is my best source of parts (hopefully not BMW)

Regards,
Erick

 

[bcsugarbush]

In regard to GSAddict's questions:
37K miles / Original hall sensor
Bike doesn't quit instantly - feels like fuel starvation because you can open throttle and get a little more out of it - but it is pretty quick.
The bike isn't getting warm at this point - starves out in less than 30 seconds from cold at this point. After it dies - won't start immediately - give it a few minutes, and it will start again.

 

[jsouth]

All -
Thanks for the great insights. Given the holiday weekend coming up, I am more interested in having the top two or three candidates in my hands to hang in hopes of a quick resolution. I am also interested in having resolved the next two or three things that may be marginal in advance of having to trailer home from a vacation gone awry.

That said - here is what I have heard:
1) Rewire hall plate or purchase new
2) Coil replace
3) Intermittent side stand switch (which I think is already bypassed)

What is my best source of parts (hopefully not BMW)

Regards,
Erick

FIRST -- The HES will need attention anyway at some point. You don't want it to need attention when you are stranded on a trip in the rain and the bike won't run.... I did mine myself and can tell you it's a tough job. I bought everything I would need to do 2 of them because my dad has the same model bike I do. If I just had one to do I'd send it to GSAddict in a heartbeat. He knows what he's doing and has done many of them.

SECOND -- check the side stand switch or wire around it. This one is almost free. But HES comes first because it will fail eventually and needs to be replaced if you keep the bike.

THIRD -- replace coil if you haven't found the problem yet. If you can find someone who'll let you test a known good coil on your bike, that would be best.

 

[paul_f]

GS Addict rewired a Hall Sensor for me. Decided not to replace it myself and was pleasantly surprised that the local BMW shop in town did the job in slightly over an hour; affordable and a lot quicker than I could have done it.

 

[gsaddict]

In regard to GSAddict's questions:
37K miles / Original hall sensor
Bike doesn't quit instantly - feels like fuel starvation because you can open throttle and get a little more out of it - but it is pretty quick.
The bike isn't getting warm at this point - starves out in less than 30 seconds from cold at this point. After it dies - won't start immediately - give it a few minutes, and it will start again.

You did not mention if you changed the fuel filter, I assume you did.
Did you inspect the U hose when in there? They typically split with age and don't allow proper fuel delivery
The fuel system pressure should be 43psi (+/-2psi) running
The return line should be delivering 2 litres/min when diverted into a suitable container.

 

[PGlaves]

I agree the HES must be rewired or replaced - they all need that. But this screams fuel delivery. So once the HES works, if the problem persists then the filter and injectors are the next suspects.

 

[roger 04 rt]

As Gs addict and Paul have suggested, you should go with your instinct and measure fuel delivery. You can start replacing parts or try to narrow things down. A return-fuel test will give a good indication of your fuel system: http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=838620#Post838620

If you still have a charcoal canister, you should check and make sure it’s unrestricted and that you’re not developing a vacuum in the tank.

 

[bcsugarbush]

Thanks for all of the great suggestions - as a recap;


I did bench tested the injectors and back-blew them in the event that something may have been clogging in front of the orifice (opened injector with 12V battery and blew backwards into a towel to see if any debris came out - nothing)
Fuel Pump: Replaced (Quantum)
Fuel Filter: Replaced when in there doing the fuel pump replacement (should have moved it out but I didn't)
U-Hose: Did not replace (inspection indicated it was stiff, but not cracked, fractured etc.)
Fuel flow: Have not measured pressure, but pulled each injector supply and let the pump clear the lines before I hooked up and tried the system - flow was strong.

Looking forward to getting to it again this weekend.

 

[roger 04 rt]

You can’t tell the condition of the in tank hoses by looking. And getting good flow with the injector off is at low pressure. The only way to know if you’re getting the right fuel flow under pressure is to measure the return volume at idle.

This may not be the problem but in tank hose failure happens so often that that you should check it.

The stock pump does 110 liters per minute at 43 psi. You should check the quantum spec.

 

[dieselyoda]

Hard start, rule of thumb, replace spark plugs. After that, check air filter.

That's just a basic start.

 

[burnbender]

I love BMW motorcycles. They give us pleasure through the ride and endurance. Along with the endurance comes maintenance and as they get older more maintenance. One thing I've learned is when a BMW is properly maintained it runs like a new bike. I remind myself I'm riding a 15 year old bike though it doesn't seem so. My Oilhead is currently down as well and believe it or not I am enjoying the learning experience. God luck with your repair and keep the wheels down.