'99 RT still cutting out

[avu3]

I started a thread back in December where Roger DR and a bunch of you helped me troubleshooting a cutting out problem which I thought was something to do with the AF-XiED.

 

That seems to have been transient, possibly related to the wiring harness. I replaced the O2 anyway (as it was old/slow/lazy) and the AF-XiED works fine now.

 

But the bike still "cuts out" on one cylinder or "misses" occasionally. It just drops a cylinder. It won't idle, but it will run if you keep giving it fuel.

 

Sometimes it happens at low speeds - I've had it happen a few times on different onramps/overpasses at 20mph or less.

 

It also happens at highway speed. Yesterday I was cruising at 75 and it just lost power and started slowing down. Adding more fuel I was able to keep pace until I was able to get off the freeway - and by the time I did, it was operating fine and kept doing so the rest of the day. That too has happened multiple times on the freeway.

 

Temp doesn't seem to matter. Its happened cold within a few minutes of startup and after an hour's riding.

 

Fuel tank state seems not to matter. Its happened with a full fuel tank as well as a mostly empty one. I guess I should still look at the fuel pump and plumbing.

 

Things I am thinking to look into

 

Fuel pump/filter/in tank hoses. Figure I'll replace the filter and hoses since I have to open it up anyway and don't know their age. That looks like about $40 in parts from BB.

 

Coil, I guess. Though I've never had one "kinda fail sometimes". Usually they fail when they get hot and stay broke till they cool. This will fail cold or hot, and usually comes back after a minute or so. But I guess I will pick up a used one off eBay and some new wires from BB. That looks like about $140/$150 in parts.

 

HES. I have been reading about them. This too seems like something that shouldn't self-correct on the go, but I guess I need to look at it, specifically the wiring. The aftermarket replacement for $200 is OOS at BB. Maybe I'll wait to see about one of those, or try my luck at DIY re-wiring it.

 

Fuel Injectors? Throttle bodies? Anyone think I should look at those? It wouldn't be hard to send the fuel injectors out to be serviced, or to replace them with the newer/upgrade path I've read about (just expensive). I noticed the TB rebuild kit on the BB site but haven't researched the frequency of needing to do it or symptoms.

 

Any other thoughts/suggestions on what to look at/for? It seems I could just keep riding it and wait for it to get worse, but part of me hates doing that and wonders what other damage I might cause - plus the inevitable getting stuck on the road somewhere at some point.

 

Dumping a bunch of fuel in the cat and making a super hot cat probably isn't a great idea either...

 

Thanks

Scott

[dirtrider]

Afternoon Scott

 

Dumping a bunch of fuel in the cat usually isn't a big problem unless you also dump a bunch of oxygen in there with it to allow the cat to light off.

 

On your problem-- It doesn't sound like the coil as the BMW coils spark BOTH SIDES from the same coil winding. But is could be a spark plug wire partially pulled out of the coil (so check that)

 

Your bike isn't an RT-P is it?? RT-P's have a shielded coil & THOSE can cause an issue like you at seeing.

 

You might also check your spark plug wire routing (especially the R/H side) as I have seen the R/H plug wire routed too close to the TB cam therefore getting worn through & shorting out to the TB cam.

 

I presume that you have tried new spark plugs? A spark plug with a crack or partially shorted center electrode can also cause similar issues.

 

 

Otherwise possibly a fuel injector that sticks closed, or valve that stays partially open on a carbon chunk can cause similar issues.

 

That is going to be a tough nut to crack until you determine IF it is lack of fuel or lack of spark causing the problems.

[avu3]

New plugs. Ones I took out appeared worn but were gapped correctly and showed the same color/wear across the cylinders.

 

Not a -P, just a regular RT.

 

 

 

 

 

 

 

 

[Michaelr11]

My R1100RT and two other local riders, also R1100RT bikes, all had issues with the bike suddenly losing the motor as though the run switch was flicked to off. In my case the bike initially would sputter and then seconds later re-fire since my road speed was still turning the engine. A few weeks later the motor died while riding but restarted after a minute or so at road side. Finally, it would not start at a gas station after a two hour warm weather ride. In all three of these cases, replacement coils made the problem go away.

[avu3]

Thanks for the feedback, Michael. My bike isn't dying entirely- it just quits running on one cylinder... so I'm not sure if a $130 coil is the thing to do yet.

 

I may pickup a used one as a spare to test it after I inspect the plug wires as DR suggests. I intend to pull them off and visually inspect them as well as test resistance, possibly while wiggling them or something looking for breaks/failure.

 

 

[avu3]

The problem came back today, much worse than ever before. I was out for a quick run between storms and tried to do a 20 mile circuit, just to get the fluids warm.

 

At mile 5 the misfire picked up. Its never lasted more than a mile. At mile 6 with no sign of it getting better I u-turned to head back home. I barely made it.

 

Sawing on the throttle would get me acceleration, but steady throttle the bike just fell on its face. It would drop all the way to dying, but start right back up and idle. Lots of misfire, popping and banging when I was sawing. Clutch in, it ran fine. Apply throttle, gentle acceleration and minimal misfire... Until I let the clutch out. So its load related.

 

Of course, 100 yards from home it cleared up and ran fine.

 

I decided since I've been through the ignition system already and didn't find anything I'll go for fuel. Ordered a fuel filter and internal lines and I'll rule out a split line or plugged filter first. Then I can move on to ignition. If a coil and wires don't fix it, I'll go for the HES.

 

Scott

[Jim Moore]

I had a similar problem once. That sounds kinda like an oxygen sensor. The computer goes to open loop when the throttle reaches a certain point, taking the sensor out of the equation. At steady throttle the O2 sensor tries to balance things out. I would try removing the cat code plug. That should take the O2 sensor out of the equation. If that doesn't help I would try disconnecting the O2 sensor. The connector is on the right side under the tank.

[dirtrider]

The problem came back today, much worse than ever before. I was out for a quick run between storms and tried to do a 20 mile circuit, just to get the fluids warm.

 

At mile 5 the misfire picked up. Its never lasted more than a mile. At mile 6 with no sign of it getting better I u-turned to head back home. I barely made it.

 

Sawing on the throttle would get me acceleration, but steady throttle the bike just fell on its face. It would drop all the way to dying, but start right back up and idle. Lots of misfire, popping and banging when I was sawing. Clutch in, it ran fine. Apply throttle, gentle acceleration and minimal misfire... Until I let the clutch out. So its load related.

 

Of course, 100 yards from home it cleared up and ran fine.

 

I decided since I've been through the ignition system already and didn't find anything I'll go for fuel. Ordered a fuel filter and internal lines and I'll rule out a split line or plugged filter first. Then I can move on to ignition. If a coil and wires don't fix it, I'll go for the HES.

 

 

Morning Scott

 

You didn't solder the wire connection on the new o2 sensor when you installed it did you? Soldering blocks reference air to the o2 sensor.

 

You have done & checked a lot on this bike already so verifying the fuel system is a good next move. Or you can install a piece of clear Tygon hose in the fuel return line, then loop that out to where you can see it. If you don't see fuel flowing back through that clear return hose when the problem is present then you know for certain that you have a fuel supply issue. If you have plenty of fuel return flowing with the problem present then you can be pretty sure that it isn't an in-tank fuel supply problem.

 

On a 1999 bike (if it were my bike) I would definitely replace or re-wire the HES. Even IF that isn't the current problem it eventually will be so might as well bite the bullet & do it now. That will also take the HES out of troubleshooting equation.

 

 

[AnotherLee]

Scott - my problem with the afxied was so similar. Here is a video of how I found the problem.

http://vid1067.photobucket.com/albums/u427/leehopp/AFxIED/AFXiED.mp4

[avu3]

Thanks Lee. The AF-XiED is out of the circuit entirely now. It might still have a super intermittent problem like yours did, but its not contributing to this mis-fire/drop out problem so I'll get back to that.

 

What is that separate black wire you did there? An auxiliary ground? Going to the blue wire?

 

 

I crimped the o2 sensor per our previous discussions - its not soldered.

 

Any opinion between the Enduralast and Bosch HES sensors? $30 to $40 difference.

 

Scott

[AnotherLee]

Scott -

 

Darn! Thought I had it.

 

You said: What is that separate black wire you did there? An auxiliary ground? Going to the blue wire?

 

That's a ground wire going directly to the battery. It came that way from the manufacturer. Don't know how it connects in the afxied harness.

[Michaelr11]

.........

 

Any opinion between the Enduralast and Bosch HES sensors? $30 to $40 difference.

 

Scott

 

IMHO the best choice would be to pull your HES out and send it out to GSAddict to be rewired.

 

[avu3]

I plan to send him mine to replace the wires and keep it as a spare.

[avu3]

I read up on the work and its something I'm perfectly capable of, so I ordered the oven control wire from McMaster-Carr and I'll re-write my HES myself.

 

I found some old threads on Pelican (2006/2007) where guys were describing the same problems I'm having. They changed coil, TPS, Throttle Position, O2, Fuel filter/lines - none of it seemed to solve the problem. Like mine, it initially ran better but then the problem returned. Neither of the OPs did injectors or the HES. Those threads are what made me move the HES ahead of doing the coil/wires like I initially planned. I'm still going to change the fuel filter and swap the in tank parts just due to age/mileage.

 

I'll update with HES wire condition when I get into it (its been too wet here to work on stuff).

[avu3]

Weather and life have kept me slow-going, but I finally managed to rebuild the fuel system. The fuel filter dates to 2008, so at least it was changed and wasn't original. The hoses showed no signs of splits and looked to be in good shape, but I replaced them anyway.

 

I reassembled everything and no leaks, and it works - so that seems to have gone ok.

 

I was fiddling with the throttle cables and noticed the left one is hyper sensitive. If I just bump it or deflect it a little the rpms change a lot. Not even lifting it up, just deflecting it 1/4 of an inch say 6" up the cable.

 

The right side, I can grab it, push it around and it really makes no impact unless I intentionally un-seat it. Then the bike dies.

 

Is that left side normal?

[Jim Moore]

Sounds like that side is overtightened. Maybe holding the butterfly open a little bit.

[dirtrider]

Weather and life have kept me slow-going, but I finally managed to rebuild the fuel system. The fuel filter dates to 2008, so at least it was changed and wasn't original. The hoses showed no signs of splits and looked to be in good shape, but I replaced them anyway.

 

I reassembled everything and no leaks, and it works - so that seems to have gone ok.

 

I was fiddling with the throttle cables and noticed the left one is hyper sensitive. If I just bump it or deflect it a little the rpms change a lot. Not even lifting it up, just deflecting it 1/4 of an inch say 6" up the cable.

 

The right side, I can grab it, push it around and it really makes no impact unless I intentionally un-seat it. Then the bike dies.

 

Is that left side normal?

 

Morning avu3

 

Depending of the severity it is normal.

 

Remember that your L/H side TB has the TPS (Throttle Position Sensor) mounted on it & the R/H side TB doesn't have a TPS sensor.

 

SO, when you lightly open the L/H side you get both more fuel to both sides & more air to the L/H side therefore a quick gain in engine RPM's.

 

On the R/H side you ONLY get more air when you open that side throttle plate so more air but no more fuel means no gain in RPM's or engine power.

 

If it's real touchy & just takes a little cable bump on the L/H side outer casing then you might have a too-tight cable.

[avu3]

Thanks guys. I considered the TPS being there, but I think the difference is too pronounced. I'm going to review the adjustments in the manual.

 

I've got to decide if I want to put it all back together and get some rides in to see if the fuel system made a difference, or if I should just go ahead and re-wire the ignition sensor.

 

Scott

[dirtrider]

Thanks guys. I considered the TPS being there, but I think the difference is too pronounced. I'm going to review the adjustments in the manual.

 

I've got to decide if I want to put it all back together and get some rides in to see if the fuel system made a difference, or if I should just go ahead and re-wire the ignition sensor.

 

Scott

 

Afternoon Scott

 

 

Ultimately you will probably want to rewire the HES but a failing or intermittent HES will not cause JUST one cylinder to drop out.

 

On the BMW 1100 both side spark plugs spark at the very same time on every piston up so if you lose one side due to HES issues you lose both sides.

 

Have you looked closely on the R/H side to make sure that the R/H side TB cam isn't contacting the spark plug wire on that side (usually happens close to idle position)

 

 

 

 

 

[AndyS]

Are you sure it is ignition and not some moisture in your fuel.

Are you sure it is just one side cutting out or have you got some stumbling misfire that could actually be on both sides of the bike?

[avu3]

I am not sure if its fuel or ignition at this point.

 

I ran the tank nearly dry twice, and drained it once and the problem has recurred. I just drained all the fuel out to change the filter and guts and put in fresh from a busy quality station.

 

I have not yet done a pressure test nor had the fuel injectors cleaned/flowed, so it could be the regulator/distributor or a sticky fuel injector.

 

I am pretty confident its only one side, but this is my first boxer so... maybe its just general ignition mayhem.

 

Scott

[AndyS]

Thanks Scott, i just wanted to clarify that we are not chasing our own tails due to stale or contaminated fuel. But, that has all been covered now.

[dirtrider]

Morning Scott

 

If you have an ohmmeter you might check your secondary side resistance just to see where you are with that.

 

Just unplug both spark plug wires from the spark plugs, then put your ohmmeter on the 200K scale, then measure from the METAL inside of one side spark plug wire (plug cap) to the metal inside the other side plug wire plug cap (basically through one wire, through the coil secondary, then through the other wire)

 

You need to see somewhere from 17K to 25K or so (depends on coil temperature & how clean the connections are)-- (17K-20K is just great)

 

If very high resistance or an open then you have plug wire or connection issues.

 

If way low 12K or less then you might have a shorted coil.

 

When it comes to BMW 1100/1150 under tank ign coils the later black or blk/red coils seldom if ever go bad (I can count the number of bad ones that I have seen in my life on a couple of fingers)-- The very early (gray colored) 13 ohm coils did have some issues but your bike is late enough that it shouldn't have one of those.

 

[SoCalBmr]

This is pretty slick! A coil test with no plastic removal! Sweet!

[avu3]

I forgot to test the coil. I forgot I was supposed to (despite suggesting it to someone yesterday). Old age I tell you.

 

I went ahead and removed the HES for inspection.

 

I cut into the shrink wrap and was thinking I'd wasted my time. I don't think this HES was original. The sensors had yellow "used part" paint marks on them. There's no BMW numbers on it, either - though it does say Bosch and Germany on it.

 

Anyway, the wiring looked fine as I peeled away the shrink wrap.

 

I was really bummed, actually wanting to find a problem I could fix since "randomly runs like crap" makes the bike tough to commute on.

 

Anyway... wiring looked fine, until I grabbed it to hold it for a little different cut (wanting to keep the wires from getting damaged by my knife). The insulation crumbled in my hands. First a few cracks. Then some little flecks. Then the big bare wires you see in others' photos. Pretty soon I had four wires with an inch of bare each, and a pile of dandruff on my bench.

 

I re-wired it. Try as I might, I couldn't get the connector apart so I ended up using about an inch of the wire at the connector. It wasn't brittle and failing like the sensor end, and I shrinkwrapped what I left, so it shouldn't be a future problem.

 

The bike runs well.

 

The starter sounds funny now, like its spinning faster and not making full engagement. More high pitched. Not sure what to make of that. I did not screw up and crank with the pin in, or anything.

 

The bike starts easier. Needs less choke. Needs less warm up. Maybe the battery reset. Maybe I moved the HES a little when I put it back on and the timing is a few degrees different.

 

There's an odd rattle when I shut the bike off. I'm afraid the pulley isn't on tight, even though I was diligent to torque it to 37 ft lbs and inspected it after running it... so I've got to pull it all back apart to look.

 

Scott

[dirtrider]

I forgot to test the coil. I forgot I was supposed to (despite suggesting it to someone yesterday). Old age I tell you.

 

I went ahead and removed the HES for inspection.

 

I cut into the shrink wrap and was thinking I'd wasted my time. I don't think this HES was original. The sensors had yellow "used part" paint marks on them. There's no BMW numbers on it, either - though it does say Bosch and Germany on it.

 

Anyway, the wiring looked fine as I peeled away the shrink wrap.

 

I was really bummed, actually wanting to find a problem I could fix since "randomly runs like crap" makes the bike tough to commute on.

 

Anyway... wiring looked fine, until I grabbed it to hold it for a little different cut (wanting to keep the wires from getting damaged by my knife). The insulation crumbled in my hands. First a few cracks. Then some little flecks. Then the big bare wires you see in others' photos. Pretty soon I had four wires with an inch of bare each, and a pile of dandruff on my bench.

 

I re-wired it. Try as I might, I couldn't get the connector apart so I ended up using about an inch of the wire at the connector. It wasn't brittle and failing like the sensor end, and I shrinkwrapped what I left, so it shouldn't be a future problem.

 

The bike runs well.

 

The starter sounds funny now, like its spinning faster and not making full engagement. More high pitched. Not sure what to make of that. I did not screw up and crank with the pin in, or anything.

 

The bike starts easier. Needs less choke. Needs less warm up. Maybe the battery reset. Maybe I moved the HES a little when I put it back on and the timing is a few degrees different.

 

There's an odd rattle when I shut the bike off. I'm afraid the pulley isn't on tight, even though I was diligent to torque it to 37 ft lbs and inspected it after running it... so I've got to pull it all back apart to look.

 

Morning Scott

 

Was the timing cup loose from the pulley? If so did you glue the timing cup back on the pulley? If not & (IF) you take it back apart then you should glue it on (it's in the BMW service manual)-- Personally I use Loctite Black Max to glue those timing cups to the pulley.

[Lowndes]

Could the "odd rattle" be an OEM cam chain tensioner (left side)?? That's easy to check just by looking at the exterior hex on the plug.

 

Lots of info on forums, EZPZ fix (remove and replace), I remember the cost was very reasonable from several parts places. If that's not the source, you might want to do the upgrade anyway while you're in there.

 

Lots of pics here: Cam Chain Tensioner OEM and Up-grade pics

[avu3]

The timing cup was firmly attached. I did check it and didn't mess with it.

 

I started it this morning and no noise, so I ran it 20mi round trip to breakfast.

 

The noise is a bearing chirp. I assume I over tensioned the alternator. It comes and goes.

 

I'd never heard the tensioner rattle before. Guess I never knew to listen to it. Listened for it coming out of breakfast and sure enough, it's there. I'll have to order the parts and do that.

 

Good golly this thing feels good. I've no idea what did it, but the idle and roll on throttle are so much smoother now. When I first got it, it felt stable and comfortable but slow. Now it's properly quick.