Stalling When Decelerating or Coming to a Stop

davidh

Member
OK, so my 2013 C650 GT just started something a little odd a month ago. When going > 30 MPH and coming to a stop, the engine stalls. I can restart it without any issue but it's certainly less than desirable.

My thought was that the clutch wasn't releasing fast enough or something else in that same area. I pulled everything apart and found that the sleeve on the drive shaft and was severely worn and appeared to be binding on the variator. Definitely my fault as I've never lubricated the inside of that sleeve as shown in the manual. Oops. Having that bind a little at idle could definitely stall the engine and make the noise I was hearing

So I replaced the sleeve and variator (lubricating as noted), the clutch (which I was doing anyway), and buttoned everything up. The transmission is MUCH quieter and doesn't make any of the nasty noises it was before. But, the stalling is there still there. It idles great, if I slowly come to a stop, everything is good, but quicker stops (or even regular deceleration) cause it to stall.

Not sure what else might be going on but hopefully something straightforward. I'm 95% sure it's nothing in the transmission area but open to ideas. THanks!
 

Scorpion56

Member
I had a '13 and I remember that in the US, there was a recall for this situation back in 2014/15 time frame. There were two situations causing a stall. One was a bad timing chain tensioner and the other was the safety engine cut off switch that is part of the center stand. Two different causes and each resulted in its own recall. If you are in the US, look at the NHTSA safety recall notices for your model year.
 

davidh

Member
I had a '13 and I remember that in the US, there was a recall for this situation back in 2014/15 time frame. There were two situations causing a stall. One was a bad timing chain tensioner and the other was the safety engine cut off switch that is part of the center stand. Two different causes and each resulted in its own recall. If you are in the US, look at the NHTSA safety recall notices for your model year.

Thanks! Both of those were done long ago. In thinking back, this all started with the last fuel-up and I haven't added any since then. I need to put on the final plastics and will take it out for a decent ride this weekend and re-fuel to rule out some wacky issue there.
 

davidh

Member
Quick update on this. I filled it up and took it for a 40+ mile ride last weekend. Same thing, when coming to a stop; the idle drops (around 15 mph) and it stalls. Consistently. On the way back home I had the emissions light come on which had never happened before. Made it home without any issues and made an appt to have the dealer check the codes (definitely happy to have a trouble code for them to use).

Long story short. they checked/cleared all the older codes, took it for a test ride, verified the symptoms, and re-scanned. It reported a problem with the oxygen sensor and a too-lean condition, causing it to stall. Definitely sounds plausible and given the mileage on the bike, maybe not too surprising. The part is on order and some $450 later, I should be in business. I'll report back.
 

davidh

Member
So here's the update and closure.

The previous mechanic diagnosed a bad oxygen sensor which, based on the symptoms, seemed reasonable. $600 later, the problem persisted. I poked around a bit but no dice. Finally found a new shop and, within an hour, he determined that a cracked hose ($22) was causing the O2 sensor to go all wonky and cause the stalling problem. It’s entirely likely the original sensor was OK and the technician just read the code and called it done. Amazing what some good diagnostic skills can do for you.

Humongous shoutout to Pasta Performance Motorsports (Rancho Cordova, California USA) for very quickly diagnosing and fixing a problem I’ve been fighting with for over a year! Nice to have it in good running condition again!!!

PS. There are two identical hoses (part number: 01 13 71 7 725 265). He couldn't totally visualize the left-side one (with the body panels pn) but I bought a second hose and will be ready to replace it down the road if needed.
 

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mjnorris

Active member
They are the “idle actuator hoses”. I had the same problem and the shop could not figure out the cause until I read about another member of the forum who had the same problem. The hoses are cheap, but unfortunately the labor is not but it should resolve the problem.
 

davidh

Member
David, general location of these hoses? I can not find any mention of them in the shop manual.

D'oh, sorry I should have taken a picture while I had the plastics off! Here's the fische picture which doesn't show lots (hose #1). You can easily see one end at the front of the engine (on each) side, maybe 4-5 inches in front of the variator.

1618931173142.png
 

davidh

Member
They are the “idle actuator hoses”. I had the same problem and the shop could not figure out the cause until I read about another member of the forum who had the same problem. The hoses are cheap, but unfortunately the labor is not but it should resolve the problem.

Thanks and I have NO idea how I missed the previous posts on it. He only charged me 2 hours -- one for diagnosis and one for replacement. I delivered it to him with the right-side body panels removed so that surely saved some $$$.
 

Pappy13

Active member
I'm having the same problem now, bike is apart on the lift waiting for hoses. They plug into the air "muffler" just above and behind the spark plugs, are routed in between the throttle bodies and plug into the engine at the 90 degree bend. You could "probably" get by with the correct size hose and route it yourself but it's formed like this to make sure all cables and linkages are not interfered with.

My scoot would stop one time and idle at 3,000 rpm, the next time would idle so low the engine would stall and you never knew what was coming. If you slowed very gradually everything seemed normal, but I had it stall a time or two leaving a stop. Only going through these symptoms so you know what to look for, it typically doesn't happen all at once and when it starts going you have a little time to order the hoses. I've got my bike naked now, doing spark plugs, these hoses, oil and filter and another coolant flush and fill. Trying to find a BMW motorcycle dealer in Atlanta has been a challenge, I need the front brake hose recall done..........
 

Pappy13

Active member
Update; replaced both hoses, flushed coolant, changed oil and filter installed new spark plugs, bike runs perfect. Front brakes feel "squishy", can't get local BMW dealer to return calls, at this point if they'll give me the hoses I'll replace them myself. Getting down to the "wear bars" on the Metzlers, have the new set of Michelins under the work bench, will finish all the maintenance and look into selling this scoot and getting a good used R1200RT. Have LOVED the scooter, never thought I would appreciate it but it's one heck of a bike, best handling bike I've ever owned, I just miss swapping my own gears.....
 
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Ceesie76

Active member
I serviced my '16 650 sport the other day and while I had my motoscan app hooked up to reset the service light, checked for codes. Got an O2 sensor fault. The bike runs perfect and never stalls, but now I'm thinking one or both of those hoses is starting to go. Will keep an eye out if it develops any issues such as described here.
 

Delray

Well-known member
This is a helpful thread and I appreciate everyone who's chipped in. With a 2013 that just hit 21,000 miles, the Idle Actuator Hoses are on my radar.

In fact, I have a gear oil change due at 24,000, which, if I follow BMW instructions instead of tempting shortcuts I've read on this forum, involves removing all the plastic and dropping the radiator and exhaust manifold. Thus, the Idle Actuator Hoses should be front and center. Is that true? Should I change them pro-actively? I already have new gear oil and manifold gaskets on the shelf, so I'm ready to go.

Someone here said it's a $20 hose but a PITA to access. So I figure as long as I'm "in the neighborhood" doing the gear oil ....
 

Pappy13

Active member
This is a helpful thread and I appreciate everyone who's chipped in. With a 2013 that just hit 21,000 miles, the Idle Actuator Hoses are on my radar.

In fact, I have a gear oil change due at 24,000, which, if I follow BMW instructions instead of tempting shortcuts I've read on this forum, involves removing all the plastic and dropping the radiator and exhaust manifold. Thus, the Idle Actuator Hoses should be front and center. Is that true? Should I change them pro-actively? I already have new gear oil and manifold gaskets on the shelf, so I'm ready to go.

Someone here said it's a $20 hose but a PITA to access. So I figure as long as I'm "in the neighborhood" doing the gear oil ....
Knowing what I know now, I would have the hoses and swap both of them while I had the Tupperware off, you will want long reach needle nose pliers to remove and replace the hoses between the throttle bodies, as you pull the hoses out tie or tape something to fish the new hoses back through the space between the throttle bodies (makes it SO much easier to get the new hoses properly routed). Mine is a 2013 also, it is creeping towards 28,000 miles now, and both hoses were compromised. Night and day difference from what it was doing to how it's running now, but I also replaced the spark plugs from the original plugs (no special tool required, just firm finger pressure and lift straight out after unplugging the coil pack) and since it was on the lift and the radiator was loose, I flushed the coolant and filled again and did the oil change that was due in another 600 miles. My hoses from Ben's were about $47.00 delivered (both).
 

Delray

Well-known member
"Night and day difference from what it was doing to how it's running now"

Helpful answer, thanks. Not sure two idle actuator hoses will enhance performance much, but I love the idea of avoiding future trouble. I will order the hoses and have a go at it.

I know what you mean about night and day difference. I bought my 2013 with 15k miles and updated belt and rollers, oil and filter, coolant, plugs and three filters (one air, two CVT). It was like a different bike. I already felt like I'd stolen it for $3900 from a Ducati dealership that wanted to get rid of it -- I was 100% sure of my theft when it ran like a new machine.
 

Ceesie76

Active member
Reviving this older thread - as my 2016 C650 Sport has started to display similar symptoms as described in this thread. Last week, suddenly it started idling noticeably higher than normal. After a minute it went back to normal. Also, yesterday with a still cold engine, it almost stalled when I wanted to accelerate, something it never did before. I scanned the ECU and the 02 sensor fault appeared. I just ordered two new idle actuator hoses (some $64 delivered with tax), I should be able to install over the coming few weeks and will report back.
 

Pappy13

Active member
Reviving this older thread - as my 2016 C650 Sport has started to display similar symptoms as described in this thread. Last week, suddenly it started idling noticeably higher than normal. After a minute it went back to normal. Also, yesterday with a still cold engine, it almost stalled when I wanted to accelerate, something it never did before. I scanned the ECU and the 02 sensor fault appeared. I just ordered two new idle actuator hoses (some $64 delivered with tax), I should be able to install over the coming few weeks and will report back.
What did you find? Are you back on the road?
 

Ceesie76

Active member
Hoses still haven't arrived, ordered almost 3 weeks ago at BMW dealership 20 miles from here. Called them today to find out what's what, left a message and nobody called me back. Maybe tomorrow I may find out when I can expect to receive 'em. Riding the bike anyway, the symptoms are relatively mild still.
 
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