02 1150RT Woes Got Me Stumped

[Boulder Dave]

Ok, long story, but I sure could use some advice. 
 

Sold my RT about 5 years ago with around 55k IIRC. Bought it back 3 months ago with 67k on it. Bike had major service two years ago, but only 5k since. 
 

Soon after I bought bike back I did two 100 mile rides with no issues. Then on my commute to work one morning about 3 miles in the bike suddenly died. It cranked great, but no fire. Got bike home and an hour or so later it fired back up. HES right?  Sent HES to be rewired. Installed rewired HES and problem continues. Bike dies once warm, but refires a couple hours later. During the cool down time I can get it to start for a few seconds then it sputters out. 
 

Here’s what I’ve done:

 

1. All new fluids
2. Brake bleed
3. Replaced battery
4. Replaced all internal tank components. Fuel pressure and flow checks fine and holds pressure
5. Bike has spark and fuel pump primes
6. injectors squirt
7. coil ohms per spec
8. visually checked wiring at ignition and kill switch
9. problem seems associated with bike warming up. Always restarts when cool. 
    

Im stumped at this point. Any thoughts or suggestions would be really appreciated. 
 

Thx. 

[dirtrider]

6 hours ago, Boulder Dave said:

Ok, long story, but I sure could use some advice. 
 

Sold my RT about 5 years ago with around 55k IIRC. Bought it back 3 months ago with 67k on it. Bike had major service two years ago, but only 5k since. 
 

Soon after I bought bike back I did two 100 mile rides with no issues. Then on my commute to work one morning about 3 miles in the bike suddenly died. It cranked great, but no fire. Got bike home and an hour or so later it fired back up. HES right?  Sent HES to be rewired. Installed rewired HES and problem continues. Bike dies once warm, but refires a couple hours later. During the cool down time I can get it to start for a few seconds then it sputters out. 
 

Here’s what I’ve done:

 

1. All new fluids
2. Brake bleed
3. Replaced battery
4. Replaced all internal tank components. Fuel pressure and flow checks fine and holds pressure
5. Bike has spark and fuel pump primes
6. injectors squirt
7. coil ohms per spec
8. visually checked wiring at ignition and kill switch
9. problem seems associated with bike warming up. Always restarts when cool. 
    

Im stumped at this point. Any thoughts or suggestions would be really appreciated. 
 

Thx. 

Morning Dave

 

You have done a lot of things so assuming they were done correctly those can be eliminated. 

 

A BMW  coil can ohm out correctly but still have problems due to internal arcing so just because it ohms out good don't assume it can't be the problem. Very few issues with the BMW 1150 single spark coil but if there was a problem with a spark plug wire or excessively wide spark plug gap then it could be damaged from internal arcing. 

 

Any chance your 1150 has some sort of add-on fuel controller (like a Techlusion)? Over the years I have seen a few of those cause a problem like yours as the engine warms up. If you have something like that try completely removing it as a test. 

 

Is your evap canister (black can on right rear)  removed? If not then make sure that it is not plugged & is plumbed incorrectly. Are you getting any type of sticking gas cap, or air wooshing in as you open the cap after riding for while?

 

Long ago I worked on an 1150 that acted something like your present problem (started good cold but quit when warm). It took a lot of testing but finally I found a problem with the Motronic 2.4 fueling computer. Kind of a long-shot but if nothing else found it might be a place to look.  

 

Another thing you might try is riding with the o2 sensor disconnected just to eliminate that as a possible cause of your issue. 

 

Also make sure that the R/H side spark plug wire is not touching or near the o2 sensor wire pigtail  as the spark cross-talk into the o2 circuit can effect the engine fueling control.   

 

 

 

 

[Boulder Dave]

4 hours ago, dirtrider said:

Morning Dave

 

You have done a lot of things so assuming they were done correctly those can be eliminated. 

 

A BMW  coil can ohm out correctly but still have problems due to internal arcing so just because it ohms out good don't assume it can't be the problem. Very few issues with the BMW 1150 single spark coil but if there was a problem with a spark plug wire or excessively wide spark plug gap then it could be damaged from internal arcing. 

 

Any chance your 1150 has some sort of add-on fuel controller (like a Techlusion)? Over the years I have seen a few of those cause a problem like yours as the engine warms up. If you have something like that try completely removing it as a test. 

 

Is your evap canister (black can on right rear)  removed? If not then make sure that it is not plugged & is plumbed incorrectly. Are you getting any type of sticking gas cap, or air wooshing in as you open the cap after riding for while?

 

Long ago I worked on an 1150 that acted something like your present problem (started good cold but quit when warm). It took a lot of testing but finally I found a problem with the Motronic 2.4 fueling computer. Kind of a long-shot but if nothing else found it might be a place to look.  

 

Another thing you might try is riding with the o2 sensor disconnected just to eliminate that as a possible cause of your issue. 

 

Also make sure that the R/H side spark plug wire is not touching or near the o2 sensor wire pigtail  as the spark cross-talk into the o2 circuit can effect the engine fueling control.   

 

 

 

 

Thx DR

 

No add on fuel programmer and canister was removed shortly after I bought bike 10 years ago. I have popped the fuel cap at each failure with no effect. 
 

I will check proximity of O2 and plug wires.

 

How does one test the Motronic?

[dirtrider]

23 minutes ago, Boulder Dave said:

 

How does one test the Motronic?

Afternoon Dave

 

If it has totally failed then each of the  outputs can be tested, but with an intermittent, or a temperature effected, Motronic about the only option is to install a "known good Motronic" as an elimination test. 

 

You can also rig up some remote 12v panel lights to things like the coil (B+) & fuel injector (B+) & fuel pump (B+)  to watch those circuits as the engine quits. 

 

You can also install a long (clear) hose in the fuel return line to see if the fuel return flow stops flowing fuel just before, and at, engine quit. (good way to catch a fuel flow issue).

 

Do you remember what your tachometer was doing just before & just as the engine quit running? (THIS could possibly tell us a LOT about the problem's root). 

 

 

 

 

[Boulder Dave]

9 hours ago, dirtrider said:

Afternoon Dave

 

If it has totally failed then each of the  outputs can be tested, but with an intermittent, or a temperature effected, Motronic about the only option is to install a "known good Motronic" as an elimination test. 

 

You can also rig up some remote 12v panel lights to things like the coil (B+) & fuel injector (B+) & fuel pump (B+)  to watch those circuits as the engine quits. 

 

You can also install a long (clear) hose in the fuel return line to see if the fuel return flow stops flowing fuel just before, and at, engine quit. (good way to catch a fuel flow issue).

 

Do you remember what your tachometer was doing just before & just as the engine quit running? (THIS could possibly tell us a LOT about the problem's root). 

 

 

 

 

I don’t believe the tach was acting up prior to the fails, but can’t be sure. 
 

Thoughts on getting a GS-911?

[dirtrider]

8 hours ago, Boulder Dave said:

I don’t believe the tach was acting up prior to the fails, but can’t be sure. 
 

Thoughts on getting a GS-911?

Morning Dave

 

Excellent tool but it's usefulness on the BMW 1150 (Ma 2.4 computer) is somewhat limited for finding problems like you are chasing. 

[JamesW]

It's problems like this that make me think fondly of an airhead.  These high tech wonders are great when all works as it should but look out and man your wallet when problems like this arise.  All your eggs are in the Motronic basket, so to speak, and I've had happier thoughts.  Oh, and have you priced a new Motronic lately?  

 

Speaking of airheads I got my eye on one.

[taylor1]

23 hours ago, JamesW said:

Speaking of airheads I got my eye on one

Still ride my airhead that I've had for 30 yrs+   If you buy one , don't forget a new pair of boots to help you stop    LOL

[JamesW]

6 hours ago, taylor1 said:

Still ride my airhead that I've had for 30 yrs+   If you buy one , don't forget a new pair of boots to help you stop    LOL

 

More lol..lol..  How true this is.  The airhead I'm drooling over is a primo condition '95 RT.  Very few were built (just over about 300) and I wonder if the last of the airheads maybe had improved brakes?  Don't know.  Thinking about selling the FJR to make room.  I just miss having an airhead.  Wife thinks I have a sickness, sometimes I wonder. lol..lol..

[Boulder Dave]

I took a couple of days off.

Here is where I am at:

Halls Sensor- Assume good as bike failed before HES was rewired and failed in identical manner with rewired HES. Probability low HES is issue.
Fuel system- All tank internals replaced, fuel pressure and flow check good. Injectors are firing. Fuel pump primes. Probability low fuel is issue.
Valve adjust- Valve check was all valves in spec. Probability very low valve lash is issue.
Wiring- I have visually inspected all wiring, clutch, sidestand switches and all appears normal. I have not removed all wire sheathing, but I am going with the wiring is not the issue.
Timing- Bike goes from running perfect to off, then gradually returns to running condition. Assume timing is good.
Motronic- Removed unit, disconnected connector and cleaned contacts, reinstalled. No obvious issues per visual inspect.
Ignition- I have spark even with bike in non-start condition. Spark does not look robust, but not really sure.

My prime suspect is ignition. I have ordered a new coil, wires, plugs. If new ignition components don't solve issue, will look for replacement motronic.

The thing that has me stumped is the bike always returns to running fine after about two hours post failure. That smacks of an electrical issue brought on by heat and/or heat expansion. It seems like a broken or shaffed wire would be more random in failure and return to running.

Damn bike.

Will report back.

[dirtrider]

Morning Dave

 

Halls Sensor- Assume good as bike failed before HES was rewired and failed in identical manner with rewired HES. Probability low HES is issue.  --  This is probably a good asumption.  

Fuel system- All tank internals replaced, fuel pressure and flow check good. Injectors are firing. Fuel pump primes. Probability low fuel is issue.  --  How did you check the fuel pressure & flow? How is your fuel pressure & flow right after it quits? If it is checked when it is running OK, or checked when it will start & run OK then nothing confirmed with this yet. Are you getting a good fuel RETURN flow right at engine quit?????????????????

Valve adjust- Valve check was all valves in spec. Probability very low valve lash is issue.  -- The valve adjustment could cause some issues but almost never a complete  engine quit so this definitely low probability.    

Wiring- I have visually inspected all wiring, clutch, sidestand switches and all appears normal. I have not removed all wire sheathing, but I am going with the wiring is not the issue. -- This being the problem  is probably low EXCEPT the red or green wires right at the steering head neck, those two wires are a known issue in engine quitting on the old BMW boxer bikes. The engine quit due to either of those two wires doesn't usually match up to your current problem but it can't be ruled out either. 

Timing- Bike goes from running perfect to off, then gradually returns to running condition. Assume timing is good.
Motronic- Removed unit, disconnected connector and cleaned contacts, reinstalled. No obvious issues per visual inspect. -- Agree it doesn't even sound close to an ignition timing issue. Still could be a Motronic issue (what is the tachometer doing right at engine quitting?????) this can tell us a LOT about the problem's root. 

Ignition- I have spark even with bike in non-start condition. Spark does not look robust, but not really sure. -- See if the spark looks any better when tested with the engine running properly.

My prime suspect is ignition. I have ordered a new coil, wires, plugs. If new ignition components don't solve issue, will look for replacement motronic. -- Still not enough solid info for me to say that, especially with you still getting a spark right at & right after engine quit. 

The thing that has me stumped is the bike always returns to running fine after about two hours post failure. That smacks of an electrical issue brought on by heat and/or heat expansion. It seems like a broken or shaffed wire would be more random in failure and return to running. --   Or smacks of a fuel flow issue like a hot pump quit, or partially plugged pump intake sock sucking shut, or possibly a plugged tank vent, etc. Are you getting fuel return flow right at engine quit?????? If so then probably not a fuel issue, if NOT then probably a fuel flow issue. 

 

At next engine quit see if you are getting a fuel spray from the fuel injectors (or at least check for good fuel RETURN flow from the rear fuel return hose).  

 

You might also replace the #5 fuse, kind of a long shot but I have seen fuses with a little crack in the fuse element that opens up when hot. But with you still having a spark after quit  this is a very low probability. 
 

[Boulder Dave]

8 hours ago, dirtrider said:

Morning Dave

 

Halls Sensor- Assume good as bike failed before HES was rewired and failed in identical manner with rewired HES. Probability low HES is issue.  --  This is probably a good asumption.  

Fuel system- All tank internals replaced, fuel pressure and flow check good. Injectors are firing. Fuel pump primes. Probability low fuel is issue.  --  How did you check the fuel pressure & flow? How is your fuel pressure & flow right after it quits? If it is checked when it is running OK, or checked when it will start & run OK then nothing confirmed with this yet. Are you getting a good fuel RETURN flow right at engine quit?????????????????

Valve adjust- Valve check was all valves in spec. Probability very low valve lash is issue.  -- The valve adjustment could cause some issues but almost never a complete  engine quit so this definitely low probability.    

Wiring- I have visually inspected all wiring, clutch, sidestand switches and all appears normal. I have not removed all wire sheathing, but I am going with the wiring is not the issue. -- This being the problem  is probably low EXCEPT the red or green wires right at the steering head neck, those two wires are a known issue in engine quitting on the old BMW boxer bikes. The engine quit due to either of those two wires doesn't usually match up to your current problem but it can't be ruled out either. 

Timing- Bike goes from running perfect to off, then gradually returns to running condition. Assume timing is good.
Motronic- Removed unit, disconnected connector and cleaned contacts, reinstalled. No obvious issues per visual inspect. -- Agree it doesn't even sound close to an ignition timing issue. Still could be a Motronic issue (what is the tachometer doing right at engine quitting?????) this can tell us a LOT about the problem's root. 

Ignition- I have spark even with bike in non-start condition. Spark does not look robust, but not really sure. -- See if the spark looks any better when tested with the engine running properly.

My prime suspect is ignition. I have ordered a new coil, wires, plugs. If new ignition components don't solve issue, will look for replacement motronic. -- Still not enough solid info for me to say that, especially with you still getting a spark right at & right after engine quit. 

The thing that has me stumped is the bike always returns to running fine after about two hours post failure. That smacks of an electrical issue brought on by heat and/or heat expansion. It seems like a broken or shaffed wire would be more random in failure and return to running. --   Or smacks of a fuel flow issue like a hot pump quit, or partially plugged pump intake sock sucking shut, or possibly a plugged tank vent, etc. Are you getting fuel return flow right at engine quit?????? If so then probably not a fuel issue, if NOT then probably a fuel flow issue. 

 

At next engine quit see if you are getting a fuel spray from the fuel injectors (or at least check for good fuel RETURN flow from the rear fuel return hose).  

 

You might also replace the #5 fuse, kind of a long shot but I have seen fuses with a little crack in the fuse element that opens up when hot. But with you still having a spark after quit  this is a very low probability. 
 

Thx. 
 

I will really focus on the red and green wiring near the neck. Ignition key wiring or other?

 

I have not noticed any unusual tach behavior.

 

All fuel tank components are new and checked with a gauge (43psi and holds). Fuel return good. Next time bike dies I will confirm fuel pressure/flow in non-start condition. I think I already did this, but will do it again to be sure. 
 

I have confirmed injectors spray in non-running condition. 
 

Fuse #5 was good, but I replaced anyway. 
 

New coil, wires, plugs will be here tomorrow. Will report back with results. 
 

Really appreciate your help!

[dirtrider]

18 minutes ago, Boulder Dave said:

Thx. 
 

I will really focus on the red and green wiring near the neck. Ignition key wiring or other?

 

I have not noticed any unusual tach behavior.

 

All fuel tank components are new and checked with a gauge (43psi and holds). Fuel return good. Next time bike dies I will confirm fuel pressure/flow in non-start condition. I think I already did this, but will do it again to be sure. 
 

I have confirmed injectors spray in non-running condition. 
 

Fuse #5 was good, but I replaced anyway. 
 

New coil, wires, plugs will be here tomorrow. Will report back with results. 
 

Really appreciate your help!

Evening Dave 

 

I will really focus on the red and green wiring near the neck. Ignition key wiring or other? -- Yes, those can cause an instant stall & no re-start

 

I have not noticed any unusual tach behavior.-- Usually an HES issue will show up in a very erratic tac just before stall.

 

All fuel tank components are new and checked with a gauge (43psi and holds). Fuel return good. Next time bike dies I will confirm fuel pressure/flow in non-start condition. I think I already did this, but will do it again to be sure.-- You might need to eventually rig up a longer return hose (clear hose) to watch that hose for fuel return flow right at engine stall.  This can quickly tell you if you are barking up the correct tree. 
 

I have confirmed injectors spray in non-running condition.-- This is somewhat confusing as you said above you had spark & this says you have fuel spray so either one or the other isn't as it seems or you are spraying in something that won't ignite.  
 

Fuse #5 was good, but I replaced anyway. 
 

New coil, wires, plugs will be here tomorrow. Will report back with results. -- Let us know on this. 

[dave_a]

FYI

My 1100 had a similar restart after a cooldown issue. Turned out to be the fuel pump relay.

Didn't see where you swapped that out. 

You wouldn't hear the fuel pump cycle on for a few seconds when the key was turned on before cranking when in failure mode.

DR had me wire LED's in parallel on the fuel pump and coil hot wires. Finally caught the issue happening. $7 relay at an auto parts store.

Dave_a

[Boulder Dave]

9 hours ago, dave_a said:

FYI

My 1100 had a similar restart after a cooldown issue. Turned out to be the fuel pump relay.

Didn't see where you swapped that out. 

You wouldn't hear the fuel pump cycle on for a few seconds when the key was turned on before cranking when in failure mode.

DR had me wire LED's in parallel on the fuel pump and coil hot wires. Finally caught the issue happening. $7 relay at an auto parts store.

Dave_a

Immediately after failure and during cool down, I always hear the pump prime. However, easy swap just to take it out of the equation. Thx. 

[Boulder Dave]

Success?

 

I’m not declaring victory yet, but the signs are promising. 
 

Installed new coil, plug wires, and plugs. Swapped horn and fuel pump relays. 
 

Took bike out for a 30 minute test ride. No fail. 
 

Going to do a few other maintenance items while Tupperware is off. Then more test rides around the hood. 
 

My money was on bad coil. 
 

Will follow up about subsequent tests just to hopefully put a bow on this thread. 
 

I appreciate all the suggestions and help. 

[MichiganBob]

Sounds promising. Perserverance pays off.

 

Enjoy that fine bike.

[Skywagon]

Swap the relays back and see what happens.... That way you can zero in on coil versus relay

[Boulder Dave]

Took the bike out again today. No fail. 
 

I am cautiously optimistic.

[Boulder Dave]

A few more test rides and no fail. My final diagnosis is bad coil. 
 

Thanks for all the help. 

[Boulder Dave]

Uggghhh.

 

After about 400 trouble free miles, the bike died again today. Same symptoms, runs fine, dies suddenly, will refire at very low and lumpy idle then die. Any throttle kills it.   After sitting for a couple hours it runs fine again. 
 

I thought after replacing the coil/wires and a 100+ miles without failing, I had fixed it. 
 

I am about ready to call it quits and part it out. 

[dirtrider]

9 hours ago, Boulder Dave said:

Uggghhh.

 

After about 400 trouble free miles, the bike died again today. Same symptoms, runs fine, dies suddenly, will refire at very low and lumpy idle then die. Any throttle kills it.   After sitting for a couple hours it runs fine again. 
 

I thought after replacing the coil/wires and a 100+ miles without failing, I had fixed it. 
 

I am about ready to call it quits and part it out. 

Morning Dave

 

The (any throttle kills it) is kind of pointing to lack of fuel so you probably need to verify the fuel flow is good. I know you did a lot with that but  until verified right AT stalling then just assuming it is good can leave you with a lot of quitting & no answers. 

 

How was the tachometer acting just before & DURING engine stalling, how about during engine cranking after engine stall?  (tac action can tell you a LOT about type of failure)

 

Personally I would  rig up remote 12v panel lights to things like the coil (B+),  fuel injector (B+),  fuel pump (B+),  to watch those circuits as the engine quits.  

 

You can also install a long (clear) hose in the fuel return line to see if the fuel return flow stops flowing fuel just before, and at, engine quit. (good way to catch a fuel flow issue).

 

Over the years I have seen a couple 1100/1150 bikes that had intermittent stalling or even full engine quitting due to a poor electrical connection "through"  the fuel pump pass-through (this one is difficult to test for as it will still show 12v TO the pump pass-through but the 12v isn't getting through the pass-through to the pump). 

 

Another thing to try is to completely disconnect the o2 sensor as a faulty o2 sensor can cause all types of poor idling , stalling, no instant engine restart after stalling, etc. 

 

Also check for the o2 sensor wire pigtail hanging down onto the hot exhaust. 

 

Diagnosing this problem needs to be done right at the time of stalling as  once it starts again it is very difficult to find the smoking gun. 

 

If this problem keeps popping up then you will either need to guess your way until you run out of money or patients, or set up a monitoring system of panel lights on key electrical items & possibly a fuel pressure gauge to try to catch whatever is causing the engine-quit issue.

 

Again, watching that darn tachometer right at stall is a very good first step. 

 

 

 

 

[PAS]

Sorry to read all of these high tech issues!  This is what chased me away from my 03 R1150RT a few years ago while it was still fine!

[JamesW]

5 hours ago, PAS said:

Sorry to read all of these high tech issues!  This is what chased me away from my 03 R1150RT a few years ago while it was still fine!

 

If you think Oilheads can be problematic can you just imagine what one of the new (1200/1250) high tech wonders could be like if it develops problems?  It could be man your wallet time! My '93 RSL is the end of the line for me as far as BMW is concerned.  At least my '10 FJR has on board diagnostics that can be accessed without any specialized equipment.  Not so beyond 2012 however.

[Boulder Dave]

13 hours ago, dirtrider said:

Morning Dave

 

The (any throttle kills it) is kind of pointing to lack of fuel so you probably need to verify the fuel flow is good. I know you did a lot with that but  until verified right AT stalling then just assuming it is good can leave you with a lot of quitting & no answers. 

 

How was the tachometer acting just before & DURING engine stalling, how about during engine cranking after engine stall?  (tac action can tell you a LOT about type of failure)

 

Personally I would  rig up remote 12v panel lights to things like the coil (B+),  fuel injector (B+),  fuel pump (B+),  to watch those circuits as the engine quits.  

 

You can also install a long (clear) hose in the fuel return line to see if the fuel return flow stops flowing fuel just before, and at, engine quit. (good way to catch a fuel flow issue).

 

Over the years I have seen a couple 1100/1150 bikes that had intermittent stalling or even full engine quitting due to a poor electrical connection "through"  the fuel pump pass-through (this one is difficult to test for as it will still show 12v TO the pump pass-through but the 12v isn't getting through the pass-through to the pump). 

 

Another thing to try is to completely disconnect the o2 sensor as a faulty o2 sensor can cause all types of poor idling , stalling, no instant engine restart after stalling, etc. 

 

Also check for the o2 sensor wire pigtail hanging down onto the hot exhaust. 

 

Diagnosing this problem needs to be done right at the time of stalling as  once it starts again it is very difficult to find the smoking gun. 

 

If this problem keeps popping up then you will either need to guess your way until you run out of money or patients, or set up a monitoring system of panel lights on key electrical items & possibly a fuel pressure gauge to try to catch whatever is causing the engine-quit issue.

 

Again, watching that darn tachometer right at stall is a very good first step. 

 

 

 

 

Ok, I think I need to get systematic about this. 
 

I’ll pull the O2 sensor connection and see what happens. 
 

Tell me more about the homemade diagnostic lights. What is “B+”?

 

Thanks!

[dirtrider]

12 hours ago, Boulder Dave said:

Ok, I think I need to get systematic about this. 
 

I’ll pull the O2 sensor connection and see what happens. 
 

Tell me more about the homemade diagnostic lights. What is “B+”?

 

Thanks!

Morning Dave

 

 B+ (Battery Plus) is just saying battery 12v positive (basically 12volts in).

 

On the diagnostic lights, just hook a small 12v (panel light) between the 12 volts "into" whatever you are monitoring & ground. So  the light stays ON when (monitored item) is powered but goes out if 12v power to that item quits.

 

This allows you monitor (actually see) if things like the fuel injectors,  or fuel pump,  or ignition coil, etc are losing 12v power causing the "engine quit"  problem.  

[Rees Fullmer]

Boulder Dave:

Did you ever find a solution to your problem?  I'm in exactly the same place with a 2002 1150RT.  Any help would be greatly appreciated!!!

Rees Fullmer

rrfullmer@usu.edu

[Boulder Dave]

2 hours ago, Rees Fullmer said:

Boulder Dave:

Did you ever find a solution to your problem?  I'm in exactly the same place with a 2002 1150RT.  Any help would be greatly appreciated!!!

Rees Fullmer

rrfullmer@usu.edu

Thought I did. But after running well for about 400 miles, it’s stalling again. Just fired it up to ride around the neighborhood, but it died before I could even get my helmet on. Hopefully, it’s near total failure which should make it easier to diagnose. 
 

Stay tuned. 

[Boulder Dave]

Ok, here’s the latest.

 

Battery shows 12.6, drops to 10 during start, bike will catch and run a bit, then die. Any throttle kills it. 
 

While it is running, voltage does not go above 12.6. Alternator belt is good and turns alternator. 
 

Swapped in  another batt and condition persists. 
 

Seems like charging system is not putting out. 
 

Thoughts?

[dirtrider]

7 hours ago, Boulder Dave said:

Ok, here’s the latest.

 

Battery shows 12.6, drops to 10 during start, bike will catch and run a bit, then die. Any throttle kills it. 
 

While it is running, voltage does not go above 12.6. Alternator belt is good and turns alternator. 
 

Swapped in  another batt and condition persists. 
 

Seems like charging system is not putting out. 
 

Thoughts?

Morning Dave

 

It should stay running at 12.6 volts & 10v cranking should start it.  If it only ran for a couple of minutes & then only at idle even if the charging system is good it wouldn't have charged the battery much.  So not enough run time to say charging system is bad (yet).   

[Paul De]

On 1/2/2022 at 9:05 AM, taylor1 said:

Still ride my airhead that I've had for 30 yrs+   If you buy one , don't forget a new pair of boots to help you stop    LOL

Sorry for the side track, but had a laugh at the brake comments.   My riding friends back when we were a young dirt racing crew always though I was so amazing at how fast I could stuff my /5 into a turn.   They all had bikes with disk brakes, and I told them it wasn’t that I wanted to carry that much speed into the corner, it was that my crappy drum brakes basically forced me into having the big coconuts!

 

Back to the story, maybe try running it up to the time temp where the stall out occurs on its center stand with a couple of box fans blowing on the cylinders to avoid melting the Tupperware. Then check could and such when hot

[Boulder Dave]

On 2/21/2022 at 3:14 AM, dirtrider said:

Morning Dave

 

It should stay running at 12.6 volts & 10v cranking should start it.  If it only ran for a couple of minutes & then only at idle even if the charging system is good it wouldn't have charged the battery much.  So not enough run time to say charging system is bad (yet).   

Ok Dr,

 

I ordered and received a handful of 12v LEDs. What is the best way to tap into the following:

 

• Left injector
• Right injector
• Coil
• Fuel pump
• Any other?

I don’t want to be too invasive. Any way to use alligator clips or similar?

 

Much appreciate your advice. 
 

Thanks!

[dirtrider]

11 hours ago, Boulder Dave said:

Ok Dr,

 

I ordered and received a handful of 12v LEDs. What is the best way to tap into the following:

 

• Left injector
• Right injector
• Coil
• Fuel pump
• Any other?

I don’t want to be too invasive. Any way to use alligator clips or similar?

 

Much appreciate your advice. 
 

Thanks!

Morning Dave

 

For this you need to be somewhat creative. 

 

Solder a length of wire on the low (ground) side of your 12 volt LED, then attach a small alligator clip on that ground wire (make wire long enough to reach from a good (clean) ground connection  to where you want to mount the LED).

 

For the high side (12v in side)  of the LED  you need to be creative. On some connections you can just get the tip of an alligator clip in on the connector terminal that you want to monitor. 

On others you will need to use a split terminal that you file or trim narrower, this is what I typically use. (see picture below).

 

You can even fold the stripped end of the wire back, then fold that over on itself a couple of times, then solder that to make a long somewhat wide soft terminal that you can stick in the the back of the motorcycle connecter touching the wire terminal that you want to monitor.  (just be creative as all you need is a connection of your LED monitoring wire to the terminal that you want to monitor). 

 

At fuel pump connector monitor green/white wire_

 

At coil connector monitor green wire_

 

At fuel injector connector (either side) monitor green/white wire_

 

 

I typically use this type of terminal as it can be bent, modified or re-worked to fit into the back of about any (unsealed)  BMW boxer connector & still make a decent connection. (by bending or twisting the smaller side blade you can get a pretty good friction fit in the back side of the motorcycle connector that you are monitoring) 

 

 

[Boulder Dave]

Got lights hooked up and disconnected O2 sensor. Now just need time to do laps around neighborhood to see if it will fail. 

[Boulder Dave]

Rode the bike around the neighborhood and it failed with my typical symptoms. I didn’t notice any fluctuation in the LED lights before it failed. It just stopped. It restarts at very low idle and lumps along for a few seconds and dies. Lights to B+ on injectors, coil, fuel pump stay on when bike is at the low idle state. When it dies, only the fuel pump light stays on. Injectors and coil light go out when engine dies. 
 

I did notice the clock on the RID had reset to zero. On subsequent restarts, the RID goes back to zero most of the time, but not each time. 
 

Thoughts?

[dirtrider]

12 hours ago, Boulder Dave said:

Rode the bike around the neighborhood and it failed with my typical symptoms. I didn’t notice any fluctuation in the LED lights before it failed. It just stopped. It restarts at very low idle and lumps along for a few seconds and dies. Lights to B+ on injectors, coil, fuel pump stay on when bike is at the low idle state. When it dies, only the fuel pump light stays on. Injectors and coil light go out when engine dies. 
 

I did notice the clock on the RID had reset to zero. On subsequent restarts, the RID goes back to zero most of the time, but not each time. 
 

Thoughts?

Morning Dave 

 

Something sounds odd here, like basically what you are seeing shouldn't/couldn't happen. 

 

So, before I  make a judgment & send us chasing our tails I need you to verify the light connections. Make sure the coil B+ monitor connection ACTUALLY goes to the coil  & that the fuel pump B+ monitor connection ACTUALLY goes to the fuel pump  (sort of sounds like they might be wrong or  mis-labeled). 

 

On the clock re-setting, that might  be due to a low battery during engine cranking (especially if you didn't run it very long but started it a lot). See if the clock is re-setting at key (off) then back (on),  or only re-setting during/right-after engine cranking. 

 

We'll find your problem (or get close anyhow) but we need to be very sure that we are looking at the correct data points. 

[Boulder Dave]

Per usual bike started this morning. 
 

In above post I noted fuel pump light stays on. WRONG. It’s the coil light that stays on. My bad. 
 

I confirmed when bike died injectors and fuel pump showed no power. Coil light stays lit with key on. 
 

Picture below taken just after bike failed shows coil light on (middle left). Two green on top are injectors.  Middle right is fuel pump. Bottoms are spares. 
 

Note voltage at <1 volt. Volt meter is wired direct to battery. I was able to move cable on + terminal by hand. Still felt snug enough to make contact. 
 

Battery spins starter fine. 

 

[dirtrider]

Afternoon Dave

 

In above post I noted fuel pump light stays on. WRONG. It’s the coil light that stays on. My bad. -- OK, that makes WAY more sense, I sort of assumed the lights were reading incorrectly. 
 

I confirmed when bike died injectors and fuel pump showed no power. Coil light stays lit with key on.-- That makes more sense as that is how it is supposed to work  That is good news as far a diagnosis goes. NOW, the trick is to try to determine IF the engine starts dying BEFORE the fuel injector/fuel pump  lights go out, or IF lights go out AFTER engine quits turning? That won't be real easy but we need that info to know where to go next. As long as you are in-gear, key is on, & clutch engaged then try to allow it to coast to a stop with the engine still spinning. What we need to know is if the fuel injector/fuel pump lights are staying on with the engine spinning (even if it isn't running on it's own).

 

Picture below taken just after bike failed shows coil light on (middle left). Two green on top are injectors.  Middle right is fuel pump. Bottoms are spares. -- Nice info panel.
 

Note voltage at <1 volt. Volt meter is wired direct to battery. I was able to move cable on + terminal by hand. Still felt snug enough to make contact. -- You need to understand this as a loose battery cable, or cable to battery post resistance can cause issues like you are seeing.  Remove battery cable from battery post then clean the battery post & cable eye ring so they make a good CLEAN connection.  If you see the clock go to 00.00 again you still have a connection problem somewhere. 
 

Battery spins starter fine.-- It won't if you are seeing low voltage on the battery cables. Is you voltmeter working correctly? What does it (volt meter) show with a fully charged battery during engine cranking? 

[Boulder Dave]

Ok, cleaned batt connection (they were already pretty clean) and very, very, snugly tightened them. 
 

Gonna go for a ride and see if I can get it to fail. If it does I won’t pull in clutch and will check FI lights. 

[Boulder Dave]

Well, this is awkward. 
 

Last two times I rode, the bike died within 10 minutes. Just rode about 30 minutes with no fail. 
 

Here is my latest theory.  Neg batt cable has built in bolt with hardware that kind of captures the neg post on batt. The pos battery cable is just a eye connector. The bolt on the pos cable is pretty small diameter compared to the eye on cable and eye on batt post. The washers appear to have concaved with torque. I think I may have been losing connection on the pos all along. I’m going to get the largest diameter bolt that will fit the cable and post and see how that goes. 
 

Thinking back, it seems very plausible. One time it failed just as I hit a sharp bump. The heating cooling fail/run I’ve been experiencing could also be explained. 

[dirtrider]

1 hour ago, Boulder Dave said:

Well, this is awkward. 
 

Last two times I rode, the bike died within 10 minutes. Just rode about 30 minutes with no fail. 
 

Here is my latest theory.  Neg batt cable has built in bolt with hardware that kind of captures the neg post on batt. The pos battery cable is just a eye connector. The bolt on the pos cable is pretty small diameter compared to the eye on cable and eye on batt post. The washers appear to have concaved with torque. I think I may have been losing connection on the pos all along. I’m going to get the largest diameter bolt that will fit the cable and post and see how that goes. 
 

Thinking back, it seems very plausible. One time it failed just as I hit a sharp bump. The heating cooling fail/run I’ve been experiencing could also be explained. 

Afternoon Dave

 

Very possible, watch your monitoring lights & voltmeter. 

 

If it is/was a battery cable connection issue then it should run OK  at higher engine RPM's (good alternator output) with your stall occurring at closed throttle lower engine RPM (very low alternator output). Especially at a lower engine RPM with a brake apply as the braking power servos  draw a LOT of current. 

[Boulder Dave]

So far all good after I replaced the + terminal hardware. Not ready to claim total victory yet, but it looks promising. 

[Boulder Dave]

Well jumped on the bike and it died again. I think this is the last straw.  
 

I will likely part it out. 

[avu3]

After all you've done, it would be disappointing to give up on it.  If you have all the test lights rigged up, it seems like there was one last data point DR was looking for as far as lights on or off at failure you should at least try and grab.

 

DR's in a far better position to give you advice than me, but one thing you described sticks with me.

 

Every time you move or remove the tank,  which I'm pretty sure you had to do to do the coil and wires, and you probably did futzing with the battery - it runs better.

I wonder if you have a collapsing fuel like or vacuum line that's leading to fuel starvation.  When you fiddle with them (move the tank) you get them to a state they're better, for a while.

 

I have an older Triumph Trophy, and if you screw up the fuel lines when you put the tank back on (which is common/easy to do) you end up in a very similar spot.  It fuel starves intermittently, but eventually gravity will re-fill the fuel bowls and you'll have enough for it to run again for a while.

 

Based on your username, are you in Boulder, CO by chance?

[Boulder Dave]

9 hours ago, avu3 said:

After all you've done, it would be disappointing to give up on it.  If you have all the test lights rigged up, it seems like there was one last data point DR was looking for as far as lights on or off at failure you should at least try and grab.

 

DR's in a far better position to give you advice than me, but one thing you described sticks with me.

 

Every time you move or remove the tank,  which I'm pretty sure you had to do to do the coil and wires, and you probably did futzing with the battery - it runs better.

I wonder if you have a collapsing fuel like or vacuum line that's leading to fuel starvation.  When you fiddle with them (move the tank) you get them to a state they're better, for a while.

 

I have an older Triumph Trophy, and if you screw up the fuel lines when you put the tank back on (which is common/easy to do) you end up in a very similar spot.  It fuel starves intermittently, but eventually gravity will re-fill the fuel bowls and you'll have enough for it to run again for a while.

 

Based on your username, are you in Boulder, CO by chance?

Not from Boulder. It’s a nickname from a mountain bike brand I used to ride. 
 

There are really only three variables at work, right?  Fuel, spark, and compression. The bike goes from running perfectly to instantly off. No sputter, no warning at all. That rules out compression and timing me thinks. If it were fuel starvation it seems there would be at least a bit of a sputter or cough before it died.  It feels like a spark interruption or fuel interruption caused by an electrical fault. 
 

You may well be right about moving something when I either disconnected the tank and/or battery. 
 

Then there is the fact the bike always returns to a running state after it sits for a few hours...

 

I am so frustrated.

 

Honestly, I have about $1,500 into the bike. I would love to get it running, but at what point does it just make more sense to cut my losses?

[dirtrider]

12 hours ago, Boulder Dave said:

Well jumped on the bike and it died again. I think this is the last straw.  
 

I will likely part it out. 

Morning Dave

 

What did your monitoring lights indicate? were they on DURING the stall or come on AFTER the stall? 

[dirtrider]

Morning Dave

 

There are really only three variables at work, right? -- Pretty well but also some other things like something in the exhaust system causing a total blockage under exhaust pressure but returning back to flow after engine total stop (I have seen this a few time in my life but not on a BMW motorcycle)

 

 Fuel,---  Very good possibility on this one (see remainder of post below)

spark,--- Another possibility, your panel light should show this (or at least the common causes of spark quit) 

and compression.--- Yes, unlikely on this one. 

 

The bike goes from running perfectly to instantly off. No sputter, no warning at all. That rules out compression and timing me thinks.--- Well it pretty well rules out compression & probably on the timing.  

 

If it were fuel starvation it seems there would be at least a bit of a sputter or cough before it died.--- Possibly but not always. A sudden loss of all fuel pressure/flow shuts the injector spray down so no fuel into the combustion chambers (it isn't like a carbureted engine that has some remaining fuel in the float bowl to use)

 

 It feels like a spark interruption or fuel interruption caused by an electrical fault. --- Very possible but it could also be something else causing the sudden quit (like a mechanical issue, see more info on that  at end of this post) 
 

You may well be right about moving something when I either disconnected the tank and/or battery. 
 

Then there is the fact the bike always returns to a running state after it sits for a few hours...--- See below

 

More on sudden fuel flow stoppage--- Over the years I have seen a few old BMW boxers that have had sudden fuel stoppage issues (not from electrical but mechanical)

 

The first is on motorcycles that has had a plugged evap canister at one time. The small carbon residue gets sucked into the fuel tank through the tank vent.  That carbon residue is small but it can plug the intake sock on the bottom of the fuel pump. If this plugs the sock in just the right way it allows the fuel pump to suck the sock in (like a sucked on soda straw), this then instantly shuts the fuel flow off until the pump quits sucking. This usually happens after the engine is run a little to warm the fuel (soften the intake sock).

 

As the motorcycle sits that plugged sock can relax a little allowing fuel through again UNTIL it sucks in again & stops the fuel flow again. (a brown colored pump intake sock is usually an indication of a degraded pump intake sock). This can sometimes cause an instant engine quit or it can cause a lack of high RPM high load engine power as it starts sucking shut. This is worth a look but with your ALWAYS an instant quit it is questionable. 

 

The other thing I have seen is a real oddball, I haven't seen it often on the BMW but have seen a couple of these,  but I have randomly seen it on a number of automobiles with electric fuel pumps (very difficult to find problem).

 

This problem is with the plastic impeller on the bottom of the fuel pump. As the fuel heats up & the pump motor heats up that pressed on plastic impeller can slip on the armature shaft.  The more it slips the more it heats the impeller then the more it slips. (this happens in a very short time frame). Once the impeller starts slipping the pump quits pumping. 

 

Allowing the bike to sit a short time can then allow the impeller to tighten up enough to pump fuel again until the next time it decides to slip again.  

 

With where you are at now, & not finding a smoking gun yet, it might be time to install a fuel pressure gauge to monitor the fuel pressure as you ride and as it quits.

 

 

 

 

 

[Boulder Dave]

3 hours ago, dirtrider said:

Morning Dave

 

There are really only three variables at work, right? -- Pretty well but also some other things like something in the exhaust system causing a total blockage under exhaust pressure but returning back to flow after engine total stop (I have seen this a few time in my life but not on a BMW motorcycle)

 

 Fuel,---  Very good possibility on this one (see remainder of post below)

spark,--- Another possibility, your panel light should show this (or at least the common causes of spark quit) 

and compression.--- Yes, unlikely on this one. 

 

The bike goes from running perfectly to instantly off. No sputter, no warning at all. That rules out compression and timing me thinks.--- Well it pretty well rules out compression & probably on the timing.  

 

If it were fuel starvation it seems there would be at least a bit of a sputter or cough before it died.--- Possibly but not always. A sudden loss of all fuel pressure/flow shuts the injector spray down so no fuel into the combustion chambers (it isn't like a carbureted engine that has some remaining fuel in the float bowl to use)

 

 It feels like a spark interruption or fuel interruption caused by an electrical fault. --- Very possible but it could also be something else causing the sudden quit (like a mechanical issue, see more info on that  at end of this post) 
 

You may well be right about moving something when I either disconnected the tank and/or battery. 
 

Then there is the fact the bike always returns to a running state after it sits for a few hours...--- See below

 

More on sudden fuel flow stoppage--- Over the years I have seen a few old BMW boxers that have had sudden fuel stoppage issues (not from electrical but mechanical)

 

The first is on motorcycles that has had a plugged evap canister at one time. The small carbon residue gets sucked into the fuel tank through the tank vent.  That carbon residue is small but it can plug the intake sock on the bottom of the fuel pump. If this plugs the sock in just the right way it allows the fuel pump to suck the sock in (like a sucked on soda straw), this then instantly shuts the fuel flow off until the pump quits sucking. This usually happens after the engine is run a little to warm the fuel (soften the intake sock).

 

As the motorcycle sits that plugged sock can relax a little allowing fuel through again UNTIL it sucks in again & stops the fuel flow again. (a brown colored pump intake sock is usually an indication of a degraded pump intake sock). This can sometimes cause an instant engine quit or it can cause a lack of high RPM high load engine power as it starts sucking shut. This is worth a look but with your ALWAYS an instant quit it is questionable. 

 

The other thing I have seen is a real oddball, I haven't seen it often on the BMW but have seen a couple of these,  but I have randomly seen it on a number of automobiles with electric fuel pumps (very difficult to find problem).

 

This problem is with the plastic impeller on the bottom of the fuel pump. As the fuel heats up & the pump motor heats up that pressed on plastic impeller can slip on the armature shaft.  The more it slips the more it heats the impeller then the more it slips. (this happens in a very short time frame). Once the impeller starts slipping the pump quits pumping. 

 

Allowing the bike to sit a short time can then allow the impeller to tighten up enough to pump fuel again until the next time it decides to slip again.  

 

With where you are at now, & not finding a smoking gun yet, it might be time to install a fuel pressure gauge to monitor the fuel pressure as you ride and as it quits.

 

I replaced fuel pump, filter, and sock early on with no change. 

 

 

 

 

[dirtrider]

Quote

I replaced fuel pump, filter, and sock early on with no change. 

Afternoon Dave

 

Well, then you can pretty well rule those things out. 

[LBump]

Where does the Hall Effect Sensor fall into this problem?  Has it been ruled out?