Won't run when cold

[No_Twilight]

I have a friend with a 97 R1100R that won't start or run smoothly when cold. If he heats the bike with a room heater it starts and runs fine. He's checked spark, fuel, valves and HES. Any ideas? --Jerry

[ShovelStrokeEd]

Is he using the fast idle control? Is it adjusted properly?

 

Try this, get the bike started and warmed up to temperature. (Ventilation counts here.)

 

Now engage the fast idle lever at the first notch, the one without spring return. Idle speed should increase to about 2000 RPM or so. If it doesn't, adjust the length of the cable below the left throttle grip till it does. Don't spend a long time running the bike at fast idle to do this, on an R you won't burn up any tupperware but you could still easily overheat your engine and cook the oil. Shut down, adjust cable, start up again and check results.

 

Once you are adjusted properly, your friend can use the 2nd step, have to hold the lever against the spring return, to start and all should be fine.

 

A word here. If it has been some time since the throttle bodies where synchronized it may be that stretched cables are the root cause of the problem. Start out by doing a thorough tune up, adjust valves, verify spark and spark plugs, good, clean fuel and then synch the throttle bodies before doing the check mentioned above.

[bmwmick]

I have a friend with a 97 R1100R that won't start or run smoothly when cold. If he heats the bike with a room heater it starts and runs fine. He's checked spark, fuel, valves and HES. Any ideas? --Jerry

 

Jerry,

Two ideas, Air Temp Sensor could be bad (in the airbox lid) or the Oil temp sensor could be defective. The are both negative temperature coefficient devices so the resistance should go down as you heat them up.

 

Mick

[No_Twilight]

Ed,

I think he had already been through just about all of your suggestions. Since this came upon him suddenly, I'm thinking it might be one of the sensors mentioned. I passed both posts on to him and will let you know what he finds out.

Thanks,

Jerry

[steveknapp]

The problem for me is I don't think I've EVER heard of the temp sensors going bad. Not saying it's not it, but would be rare.

 

But I have seen many bikes that folks thought was properly setup but with no real useful fast idle. There should be little to no slack in any of the throttle cables.

 

The other thought would be the battery or some oil that's too thick?

[ShovelStrokeEd]

Proof of the pudding on the temp sensors is that the bike runs fine when it is warm. If either of them failed, and I believe only the air temp sensor actually reports to the Motronic, the bike would get worse as it heats up.

[bmwmick]

Proof of the pudding on the temp sensors is that the bike runs fine when it is warm. If either of them failed, and I believe only the air temp sensor actually reports to the Motronic, the bike would get worse as it heats up.

 

Ed,

It depends on how they fail. Both the Air temp sensor and the oil temp sensor are fed to the Motronics unit for cold start and mixture/timing control. He has MA2.2 on his '97 R1100 and may even have a fault code set if one of the two sensors are out of spec. 1223 (engine temp sensor) or 1224 (air temp sensor).

 

 

Mick

[No_Twilight]

Thanks guys. I sent him a link on how to read his motronic fault codes but haven't heard back yet. I'll let you know what he finds out. Thanks, Jerry

[Jim Moore]

Thanks guys. I sent him a link on how to read his motronic fault codes but haven't heard back yet. I'll let you know what he finds out. Thanks, Jerry

Is there something like that for an R1150? I am starting to investigate my significant drop in MPG.

[Ken H.]

Thanks guys. I sent him a link on how to read his motronic fault codes but haven't heard back yet. I'll let you know what he finds out. Thanks, Jerry

Is there something like that for an R1150?

Unfortunately, no. To read the 1150 codes you need the dealer's diagnostic system.

[No_Twilight]

Well, apparently when he started working on it he made a contingency appt with the dealer. The appointment came so he took it in. They diagnosed a faulty "engine temp sensor" and replaced it. He rode it to work and last night (very late, he's on swing shift) it wouldn't start. So now he's into the situation I've been in before: pay the dealer to fix it and then fix it yourself. I now just skip to the last step.

 

I assume they're talking about the oil temp sensor. We both have the Haynes manual and apparently this sensor was omitted. We can't find it in the manual. Does anybody know where it is?

 

And BTW, his name is Derek and he has registred for this discussion group and is waiting for his account to be approved (damn spammers cause this delay, I know) so he may jump in here at any time.

 

Thanks,

Jerry

[bmwmick]

I assume they're talking about the oil temp sensor. We both have the Haynes manual and apparently this sensor was omitted. We can't find it in the manual. Does anybody know where it is?

 

 

Thanks,

Jerry

 

Jerry,

On my '96 R1100RT it is just below the HES connector under the fuel tank and on the right side of the engine. None of the parts diagrams have it located correctly.

 

Mick

[matanuska]

Hi everyone,

 

Thanks for all of your responses. I finally got my “clearance” to post here so now I can update you all on what I’ve found so far.

 

I should have known something was up when I picked up the bike from the dealer and they said, “we found a problem with the engine temperature sensor and we fixed it”. Notice, they didn’t say the word “replace”.

 

Anyway, I spoke with the service manager at the dealer and he told me they found that the #7 fuse was blown (I don’t have the schematic in front of me but I do remember a fuse in the oil temp sensor circuit). When they took the sensor out and cleaned it up a bit, it seemed to stop the fuse from blowing. He also said they tested the sensor by immersing it in hot water and it’s corresponding resistance changes were in spec.

 

We both speculated that maybe the blowing fuse could possibly be an indication of a short in the wiring, as the sensor itself appears to be OK. He also told me that if the fuse blows and the sensor becomes inoperative, the Motronic will set default timing and mixture values to 70F, which is why it won’t start when cold but will run fine when warmer. This could also explain why I’ve noticed a recent decline in my MPG - the fuel mixture is in effect remaining constant, not regulated to optimal settings for changing engine temperature.

 

I’ll try to do some more troubleshooting tonight to see if I can find anything in the wiring.

 

Thanks again for all the suggestions.

 

Derek

 

BTW – I also asked where the sensor is physically located – under the fuel tank on the right side of the engine. Thanks Mick!

[big-t]

Welcome Derek,

 

Anyway, I spoke with the service manager at the dealer and he told me they found that the #7 fuse was blown (I don’t have the schematic in front of me but I do remember a fuse in the oil temp sensor circuit). When they took the sensor out and cleaned it up a bit, it seemed to stop the fuse from blowing. He also said they tested the sensor by immersing it in hot water and it’s corresponding resistance changes were in spec.

 

 

There is no fuse in the oil temp circuit,the motronic only reads the resistance value of the sensor,so there is no need for a fuse in that circuit.

 

 

According to my antique service manual the #7 fuse powers the heated handgrips and its pretty doubtful that a blown fuse in that circuit would keep the bike from starting.

 

Since the dealer has checked the oil temp sensor,maybe you should start with the basics.When its cold and won't start,pull a plug out and see if its firing,check the plugs to see if they are wet with fuel(indicates the plugs are not firing)if dry pull an injector and turn the engine over to see if its spraying.

 

 

Try opening the throttle a bit and see if that helps.

 

You need fuel,spark,compression for it to start,of course it helps if they are delivered in the correct sequence.

 

 

Thats a place to start,after you check the basics then you can move on from there.

[bmwmick]

We both speculated that maybe the blowing fuse could possibly be an indication of a short in the wiring, as the sensor itself appears to be OK. He also told me that if the fuse blows and the sensor becomes inoperative, the Motronic will set default timing and mixture values to 70F, which is why it won’t start when cold but will run fine when warmer. This could also explain why I’ve noticed a recent decline in my MPG - the fuel mixture is in effect remaining constant, not regulated to optimal settings for changing engine temperature.

 

Derek,

Welcome to the forum! Some of what the dealer told you is true. Most of it is BS. F7 has absolutely nothing to do with the Motronic and temperature sensing. The part about the default values is true.

You could remove the Air Temp sensor (as I mentioned earlier) and put an Ohm Meter on it. Heat it with a lighter or a pan of hot water and as the sensor heats up, the resistance should drop.

Did the dealer read out the Motronic fault codes? A defective sensor 'should' set a code.

 

Mick

[matanuska]

Yes, I finally broke open my Haynes manual and fuse #7 is for the heated grips – which I don’t have! Now I'm definitely becoming suspicious about either their integrity, or competence.

 

I’m still pretty sure this must be some kind of temperature related problem though. Wednesday morning, at the dealership, the engine started fine, as they had pushed it out of their garage and into the sun for about an hour before I got there. Wednesday night after work, it would not start at all, temp was probably in the high 40’s at that time. Thursday morning, after sitting in may garage all night, it was difficult but did finally start on it’s own. Temp in my garage, though not heated, was probably mid to high 50’s. When the egine won't start, warming it with an external heater, or repaeted cranking will get it to start. Once started and warm, it can be shut down and restarted with no apparent symptoms.

 

The other night, before I took the bike into the dealer, I did manage to check the air temp sensor (it was the only one I knew where to find at the time). I didn’t get to Ohm it out but gently warming with a heat gun had no effect on starting. In fact, completely unplugging the sensor had no effect on whether the engine would start or not, whether hot or cold. The engine (oil) temp sensor seems like they only temperature related device left. Fortunately this is my last week of ridiculously long hours at work so I’ll have time to start troubleshooting again.

 

Regards

 

Derek