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R1100RT erratic idle


Reecehk

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I have had my R1100RT for a few years now and it always had an idle problem.

Once the bike gets to normal temperature the bike idles fine at times around 1,000 rpm but other times it wont idle it just dies, especially at the worst times, intersections, traffic lights etc.

The condition is worse if the bike has been stopped/parked for an hour or so then driven (temperature shows 2 bars, roughly).

During normal riding the bike runs quiet and smoothly, it is just the idle.

Any ideas where I could look? I recently replaced the spark plugs, air filter and adjusted the valves, made no difference.

 

Just out of curiosity I noticed a small hole on the RH side in the fairing just below the knee pad, it has a screw/adjuster, looks like it goes to the RH throttle body. Odd that it is on one side only.

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I have had my R1100RT for a few years now and it always had an idle problem.

Once the bike gets to normal temperature the bike idles fine at times around 1,000 rpm but other times it wont idle it just dies, especially at the worst times, intersections, traffic lights etc.

The condition is worse if the bike has been stopped/parked for an hour or so then driven (temperature shows 2 bars, roughly).

During normal riding the bike runs quiet and smoothly, it is just the idle.

Any ideas where I could look? I recently replaced the spark plugs, air filter and adjusted the valves, made no difference.

 

Just out of curiosity I noticed a small hole on the RH side in the fairing just below the knee pad, it has a screw/adjuster, looks like it goes to the RH throttle body. Odd that it is on one side only.

 

 

Morning

 

Lots of possibilities on this one.

 

Does your bike still have the original CCP in the fuse box? If not then that can effect engine idle quality/speed during engine warm-up. (something to look at or try is going back to the factory CCP if yours is not factory configuration)

 

High alcohol containing fuel can also effect engine idle during engine warm-up conditions.

 

A failing or poisoned o2 sensor can also effect or cause an erratic, idle especially just as the o2 heats & comes on line.

 

Probably the hardest one to diagnosis or to cure is: If your bike was built before February of 1998. The early (pre 1/98) Motronic (fuel control computer) had a glitch that allowed engine stall during engine warm-up (ie until hot) & the fueling control sensor string reached a stack up of sensor values that allowed the idle speed to drastically drop. (BMW fix was to replace the Motronic with a later calibration Motronic.

 

About all you can do is to go through all the possibilities & verify that all settings & adjustments are at factory settings or values then work from there.

 

Back in the day when we had a chronic 1100 staller during dropped throttle (& during warm-up ride away) we would just set the base curb idle to max (or slightly higher) & that would usually cure the stalling.

 

As for the R/H knee pad access & that hole-- that is a carryover from the early 1100RT that used the single cable crossover system as most adjustments were done on the R/H side. It can still be used for limited (one side) BBS adjust or cable access but most just remove the Tupperware & do it the right way.

 

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Hi DR, I am hoping for a quick fix but am starting to see that this may not be the case. I don't know what the "CCP" is something contact point? I think the alcohol content is out, I don't think garages here in Aust are allowed to mix this in the fuel, I always use BP fuel here high octane 98.(if that means anything)

 

Sometimes the engine just seems to suddenly die when idling though this may be simply due to the high compression. I will have to check the date of manufacture, (found it 07/98) (it is a 75th anniversary model)

 

I read that I may have to do a TBS test, does anyone know of a reasonably priced one that will suffice?

 

Thanks.

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Hello, Reece -

 

I read that I may have to do a TBS test, does anyone know of a reasonably priced one that will suffice?

There has been a lot of discussion about throttle body sync tools - seems like everyone has their favorite. Here's a recent thread that includes a homemade manometer. Link

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Hello, Reece -

 

I read that I may have to do a TBS test, does anyone know of a reasonably priced one that will suffice?

There has been a lot of discussion about throttle body sync tools - seems like everyone has their favorite. Here's a recent thread that includes a homemade manometer. Link

 

 

If you want cheap and sensitive, I don't know that you can beat a homemade manometer, as Lee mentioned above. HERE is the link to the one I made and have been using for several years. I hang it in the corner of my tiny garage, but they are honestly almost cheap enough to be disposable if you didn't have a space to store it.

 

edit: CCP = Cat. Code Plug and HERE is another thread on this forum with loads of info on them.

 

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Hi DR, I am hoping for a quick fix but am starting to see that this may not be the case. I don't know what the "CCP" is something contact point? I think the alcohol content is out, I don't think garages here in Aust are allowed to mix this in the fuel, I always use BP fuel here high octane 98.(if that means anything)

 

Sometimes the engine just seems to suddenly die when idling though this may be simply due to the high compression. I will have to check the date of manufacture, (found it 07/98) (it is a 75th anniversary model)

 

I read that I may have to do a TBS test, does anyone know of a reasonably priced one that will suffice?

 

Morning Reecehk

 

The CCP is the Coding Plug (in the underseat fuse box) that sets the fueling computers base fueling & spark control mapping.

 

The problem we are going to have with your bike is we don't know what emission content BMW used on the Australian 1100RT in the time frame your bike was sold.

 

Does your bike have a catalytic converter as that will narrow it (CCP choice) down somewhat.

 

I'm betting it doesn't have an evaporative emission system.

 

In any case the CCP (presuming your bike came with one) should be located where the picture posted below shows.

 

As far a TBS test goes (I presume you are referring to a Throttle Body Sync check) is easy to do with a homemade U tube manometer but you say the bike runs & idles good hot so that tells us the TB sync isn't that far off. If anything I would more believe your base (curb) idle is on the low side of spec. That could be due to some TB shaft/bushing wear or more than likely coked up BBS (Big Brass Screws) idle air by-pass screws in the Throttle Bodies.

 

Before doing any sort of TB sync I would suggest that you remove the Throttle Body BBS screws & clean the screw tips & the air passages under the screws as coked up BBS passages & screw tips are a BIG part of stable idle & proper idle speed.

 

CCP_view_zpsvz7awqx0.jpg

 

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I have taken a pic of the CCP plug, but I wouldn't have a clue what to do with it!!! I looked at the link that szurszewski supplied but it is rather confusing!!!

CCP%20Plug_zpswdumiyt7.jpg

 

Sometimes the bike won't idle when it is up to normal operating temperature, it can be idling fine and drop so rapidly I don't get a chance to use the throttle before it dies. It is worse though when it is in that middle temp zone, not cold and not hot. (2 to 3 bars).

I will see if I can find where and how to do the BBS screws, I only have the Haynes manual.

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Evening Reecehk

 

Your CCP is missing?

 

The problem we now have is figuring out (IF) your (Australian) bike came with a CCP from the factory. And if it did which one.

 

I have read of some Australian bikes coming without a CCP but I just don't know enough about your import bikes to say what is going on there.

 

What I can say is (IF) your bike has a catalytic converter then it requires a CCP of some sort.

 

So can you tell us if your bike has a catalytic converter?

 

Can you also tell if there is an o2 sensor in your exhaust system?

 

If it has a cat then next we will have to determine if it came with a factory evap system or an idle trim pot. (that requires a different CCP)

 

Hopefully Roger will chime in here as he has done some recent research on CCP usage. (way more recent than what I did years ago)

 

1100%20cat2_zpspcqdb1b4.jpg

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There is definitely no oxygen sensor, I can get my hand right around the pipe. The bottom right pad near the brake pedal has a screw and can be removed easily, the pipe can be accessed through this.

I can't see the top of the muffler box to see if there is anything there, my guess is no cat converter though the box looks the same.

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With the bike running spray wd40 on the intake manifold to the rubber bellows gasket that connects to the throttle body. If you get blue smoke out of the exhaust replace the bellows gaskets. I'd feel the back sides of the gaskets for cracks.

 

 

 

 

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Morning

 

It looks like RTCHIEF wants to step in here & work with you on this so I will step aside & let him take over.

 

If you need any specific info that I can provide feel free to PM me directly.

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I will have to wait till I can get the tupperware off, I only have an open shed and the weather here sucks, every day here for the next week the temperatures are close to 40C.

Once I can get back to the job I will post a report.

Also I am going to make a manometer, it will be interesting to see what happens.

Thanks.

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Hello, Reece -

 

If you want cheap and sensitive, I don't know that you can beat a homemade manometer, as Lee mentioned above. HERE is the link to the one I made and have been using for several years. I hang it in the corner of my tiny garage, but they are honestly almost cheap enough to be disposable if you didn't have a space to store it.

 

Hi, I have had a few attempts to get the auto trans fluid to flow down the tube, all goes well till I cut the flow at the right point. From here as it travels down the tube breaks apart leaving air gaps over about 2 feet of the tubing.

How do I get the air gaps out?? :(

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Hello, Reece -

 

If you want cheap and sensitive, I don't know that you can beat a homemade manometer, as Lee mentioned above. HERE is the link to the one I made and have been using for several years. I hang it in the corner of my tiny garage, but they are honestly almost cheap enough to be disposable if you didn't have a space to store it.

 

Hi, I have had a few attempts to get the auto trans fluid to flow down the tube, all goes well till I cut the flow at the right point. From here as it travels down the tube breaks apart leaving air gaps over about 2 feet of the tubing.

How do I get the air gaps out?? :(

If you close one end of the tube with your finger then hold the other end at a higher level and the air should go to the top of the liquid. Then just bring the liquid end higher and the liquid should then be pretty free of air.

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  • 1 month later...

The weather has been awful here lately so I have only recently taken the bike out for a ride. I purchased an additive "Injector Cleaner", went for a run and that fixed it!!! Idles steady now, just a bit low, around 850RPM but hasn't stalled once over 2 days of around 500kms.

When I service the bike next and remove the side panels I will try the TBS test, I have the Manometer ready for use now.

Thanks.

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