Engine quits while downshifting

[smutny]

The bike is a 2000 R1100R with 51K miles.

 

This has happened three or four times in the last four months. When downshifting, every time this happened I was coming to a light, the engine quits. It's either from 2nd to 1st, or 3rd to 2nd.

 

The bike starts right up again, but I've been puzzled as to what could cause the engine to shut off.

[Bigfish]

I had this happen for months and I link it to broken red wire to the ignition.

Since fixing the ignition harness, problem went away.

In My case, I just installed a brand new harness, but when I inspected the original red wire, it was broken.

Try this.

1. Put bike on center stand

2. Start bike in neutral.

3. Turn Handlebar full left and full right.

 

If your bike cuts out when turning bars, suspect a bad connection.

 

Hope this helps. Good luck.

[dirtrider]

Afternoon smutny

 

 

It could be a lot of things from a low curb idle RPM, to a failing o2 sensor, to an engine sensor acting up, to about normal for cooler weather riding on early R bikes.

 

The usual short term fix is simply increasing the engine idle RPM a little.

 

If the bike otherwise runs good then my personal suggestion is to just ride the bike until warmer weather to see if the stalling goes away. If it does then your bike probably fits the BMW service bulletin on cool weather stalling on the 1100 R (not RT). Not much you can do about it now as that bike is long out of BMW support & you sure don't want to buy a new Motronic.

 

Also a slight possibility that the o2 sensor is causing your stalling so possibly a new o2 sensor might cure your stalling. (personally I would only go here IF the engine still stalls when the weather warms up)

 

If the problem really bothers you then just raise the base warm curb idle a little as that usually cures the stalling on dropped throttle on the 1100 R bike.

 

 

[eddd]

The bike is a 2000 R1100R with 51K miles.

 

This has happened three or four times in the last four months. When downshifting, every time this happened I was coming to a light, the engine quits. It's either from 2nd to 1st, or 3rd to 2nd.

 

The bike starts right up again, but I've been puzzled as to what could cause the engine to shut off.

 

If your idle speed seems a bit too low you might use your fast idle or "choke" lever to raise it the idle speed up a little. This could help diagnose the problem, but an idle that is too high can also mask other possible causes for the engine stalling.

[smutny]

Bigfish - I don't think it's in the system up there, as all the times it's happened, I was decelerating in a straight line.

 

dirtrider - I always felt she was a bit cold blooded, almost always have to use the "choke" when starting, unless I just shut off the engine, like refueling. I might up the idle a couple hundred RPM and see how she acts in the summer.

[dirtrider]

 

dirtrider - I always felt she was a bit cold blooded, almost always have to use the "choke" when starting, unless I just shut off the engine, like refueling. I might up the idle a couple hundred RPM and see how she acts in the summer.

 

Evening smutny

 

Yes, upping the curb idle by a hundred or two usually stops the dropped throttle stalling on the 1100 R bikes.

 

Just make sure you do it with the BBS screws as turning the base idle stop screws or using the choke probably won't allow the TPS voltage to drop below the .400v idle threshold so you won't learn much as it won't go into curb idle mode.

 

[Tri750]

My R1100RT does that from time to time. Maybe 3-5 times a year.

Just proving it has a sense of humor I guess.

[smutny]

Well, it was another problem... yet to be diagnosed.

 

After having no issues since my post here, today I actually had to have her towed home. While cruising along, in city traffic, a few times the engine acted like it was starved for fuel or air and quit. A few times I got it restarted, but finally while trying to limp home, no more starting.

 

While waiting and poking around, looks like I wasn't getting a spark anymore. So I'll be looking at the electrical real hard.

 

Back to the garage...

[dirtrider]

Evening smutny

 

 

Sounds a bit like your HES is going south on you.

[eddd]

 

Sorry to hear your troubles continue. R1100 bikes are well known for having HES wiring that can deteriorate due to heat and time.

 

If your problem turns out to be the HES here is a link that describes the wire problem and solution in detail.

 

Oddly some early R1100S models had the more robust wire used on their HES.

[smutny]

Well, I think you're right it's the HES. From the document in the link:

 

Typical Symptoms:

- Difficulty Starting - YES

- Sudden Engine Shutdown - YES

- No spark - YES

- No fuel pressure - NO

- Bouncing tach - YES

- Engine restart when cool - YES

 

However, the next section has this:

 

Clutch safety cutoff switch:

- Engine will not turn over with bike in gear and clutch out - YES

- Engine will turn over with bike in gear and clutch in - NO

 

So it looks like I have an issue with my clutch safety switch.

 

So, between the two issues, I'll be busy the next few nights.

 

Had the HES go out on my Saab a couple years ago. That was an easier fix...

[Jim Moore]

The clutch switch is easy. Cut the wires going to the switch at the handlebar and wire them together.

[smutny]

Didn't think of that... Already ordered a replacement. But, I'll give this a try and send it back if the bypass works well enough.

[Andyorks]

Check the side stand safety switch and wiring to it, it happened to me, the downshift was moving the side stand switch cable and causing the bike to cut out. Symptoms seemed just like fuel?air starvation...

[smutny]

I thought about that, but yesterday it would cut out even if I wasn't shifting at that moment.

 

And would the sidestand switch also cause the tach jump like the HES? That caught my attention during one of the incidents, but I didn't connect it to the HES until the document listed in the link above.

 

FYI - That document points to a vane sensor that is no longer produced. I may have found a substitute, will post that when I know for sure.

[AndyS]

What 'vane sensor' are you talking about?

Are you talking about the HES?

If you are, then it is generally not the HES that fails. It is the wiring that connects it into the main bike loom.

[smutny]

Andys, you're correct. The document in the link has an exercise on testing the sensors. Should they be bad, or if I bugger up the rewire, I'd like to have the replacement parts on hand.