Jump to content
IGNORED

hot start issue


JamesW

Recommended Posts

I have a somewhat perplexing minor problem with my RS that began actually several years ago. On a cold start she fires right up and fast idles without issue. I can ride off after maybe 30 seconds at idle without issue and all is well. If I stop and shut down the motorcycle with the engine at full operating temperature and after a few minutes restart all at first seems normal. The bike starts right up but then the idle speed begins to drop and become slightly erratic. If I ride off the engine almost seems to misfire and run a bit rough. This condition lasts about 30 seconds or so and then she smooths out and all seems well. If I start up then rev the motor a couple times before moving off all seems normal. The bike has a new set of EV14 balanced injectors which made no difference with this erratic hot start behavior. I do use a wideband O2 sensor with LC-2 controller. I tried my spare wideband O2 sensor which made no difference.

 

I can't imagine why the bike does this and I hate to think the Motronic ECU might be the culprit. Other than this little issue the bike runs beautifully with great throttle response and very smooth idle especially after the EV14 injector install. I view this problem as a minor one since it doesn't get worse and only effects the first 30 to 60 seconds of operation after a hot restart. Still, it is something that isn't right and I would like to know the cause.

 

You know I might have asked this question here before but can't remember. It's just one of those things I don't think about much I guess because the bikes runs so great 99.9% of the time.

Edited by JamesW
Link to comment
I have a somewhat perplexing minor problem with my RS that began actually several years ago. On a cold start she fires right up and fast idles without issue. I can ride off after maybe 30 seconds at idle without issue and all is well. If I stop and shut down the motorcycle with the engine at full operating temperature and after a few minutes restart all at first seems normal. The bike starts right up but then the idle speed begins to drop and become slightly erratic. If I ride off the engine almost seems to misfire and run a bit rough. This condition lasts about 30 seconds or so and then she smooths out and all seems well. If I start up then rev the motor a couple times before moving off all seems normal. The bike has a new set of EV14 balanced injectors which made no difference with this erratic hot start behavior. I do use a wideband O2 sensor with LC-2 controller. I tried my spare wideband O2 sensor which made no difference.

 

I can't imagine why the bike does this and I hate to think the Motronic ECU might be the culprit. Other than this little issue the bike runs beautifully with great throttle response and very smooth idle especially after the EV14 injector install. I view this problem as a minor one since it doesn't get worse and only effects the first 30 to 60 seconds of operation after a hot restart. Still, it is something that isn't right and I would like to know the cause.

 

You know I might have asked this question here before but can't remember. It's just one of those things I don't think about much I guess because the bikes runs so great 99.9% of the time.

 

 

Morning James

 

I do believe the place I would start is to disconnect the LC-2 (I don't believe your early bike has a CCP to remove does it?).

 

If disconnecting the LC-2 cures the problem then you will have to work with that end of things (or live with the warm start issue).

 

Added: are you able to log from the LC-2? --If so then maybe try trapping some data while the problem is present.

Edited by dirtrider
Link to comment

Hi D.R., No code plug as such but the wiring harness has an internal jumper that is the equivalent of, if I remember correctly, a yellow code plug. Good suggestion to disconnected the LC-2 and see what happens. Will wait for the next break in the weather and give it a try. Might be interesting to see how it runs with just the EV14 injectors. Other than that I think you're right about just living with it especially if it's Motronic related. Too bad a GS911 won't do any good.

Link to comment
I had the same problem when there was a Techlusion controller installed on my 03 1150RT. Never was able to get it sorted with that unit.

 

Yeah, early on I tried a Techlusion on my '04 R1150RT (sold) which never did much good since the Motronic would just lean the mixture towards 14.7:1 anyway which pretty much canceled out any benefit from the Techlusion. Also, if I remember right, I did have a similar problem with the Techlusion on the RT now that you mention it. I kind of miss that RT.

Link to comment

Is there an ambient temperature sensor? Since you point out that this only happens on a hot start, then one might suspect that a temperature sensor is malfunctioning.

Link to comment

JamesW - although the symptom you describe isn't exactly the same as what I have seen previously, it seems close enough that I'll venture this as an option.

 

Your R1100RS has a single ignition coil (12 13 1 341 978) with two terminals for the spark plugs. The coil sits up near the triple tree, over the engine. It is very possible that your coil is starting to fail and when you park for a short break the engine heat is rising up and soaking into the coil. It runs poorly for a little while and then with airflow cools enough to run normally. Used coils are available for under $100. The same coil was also used on R1100R, R1100GS, R1100S, R1100RT, R1200C and R1150 models in the early years before they switched to dual spark ignition.

Link to comment
JamesW - although the symptom you describe isn't exactly the same as what I have seen previously, it seems close enough that I'll venture this as an option.

 

Your R1100RS has a single ignition coil (12 13 1 341 978) with two terminals for the spark plugs. The coil sits up near the triple tree, over the engine. It is very possible that your coil is starting to fail and when you park for a short break the engine heat is rising up and soaking into the coil. It runs poorly for a little while and then with airflow cools enough to run normally. Used coils are available for under $100. The same coil was also used on R1100R, R1100GS, R1100S, R1100RT, R1200C and R1150 models in the early years before they switched to dual spark ignition.

 

Afternoon Michaelr11

 

The 1993 1100RS didn't come with the later design 12131341978 ignition coil . The 12131341978 coil came much later in the 1100 development time frame. The 1993 (pre about late 1996 or so) 1100's came with a steel-laminated-center coil.

 

The 12 13 1 341 978 sealed coil is the current "replacement" coil for all the 1100 bikes as that is all that's in the BMW system now but that coil wasn't available in the early 1100 production days.

 

 

 

 

Link to comment
Is there an ambient temperature sensor? Since you point out that this only happens on a hot start, then one might suspect that a temperature sensor is malfunctioning.

 

Afternoon Cap

 

The BMW 1100/1150 boxers have both an IAT (Intake Air Sensor) in the air box & an oil temperature sensor on the engine.

 

The oil temperature sensor is the major player for fueling control with the IAT being a minor player & seldom if ever causes any problems. As a rule temperature sensor malfunctions cause cold start/cold idle issues as well a rideablity problems not hot engine starting problems.

 

Link to comment
...Since you point out that this only happens on a hot start, then one might suspect that a temperature sensor is malfunctioning.

 

The BMW 1100/1150 boxers have both an IAT (Intake Air Sensor) in the air box & an oil temperature sensor on the engine.

 

The oil temperature sensor is the major player for fueling control with the IAT being a minor player & seldom if ever causes any problems.

 

Thanks. My point is that if a malfunctioning temperature sensor is indicating "cold" then the computer will compensate with a rich A/F mixture. And when the engine is warm, a rich mixture will make it somewhat harder to start. But once running, the rich mixture will be almost unnoticeable. Other factors, like the EV14 injectors, might also be exaggerating the effect of a malfunctioning sensor. Food for thought.

Link to comment
...Since you point out that this only happens on a hot start, then one might suspect that a temperature sensor is malfunctioning.

 

The BMW 1100/1150 boxers have both an IAT (Intake Air Sensor) in the air box & an oil temperature sensor on the engine.

 

The oil temperature sensor is the major player for fueling control with the IAT being a minor player & seldom if ever causes any problems.

 

Thanks. My point is that if a malfunctioning temperature sensor is indicating "cold" then the computer will compensate with a rich A/F mixture. And when the engine is warm, a rich mixture will make it somewhat harder to start. But once running, the rich mixture will be almost unnoticeable. Other factors, like the EV14 injectors, might also be exaggerating the effect of a malfunctioning sensor. Food for thought.

 

Hmmmm....That's an interesting thought and I don't have an answer. I could easily test the air temp sensor.

 

I thought about it and if this were the case then the condition I described wouldn't correct itself within the first 30 to 60 seconds after engine start with the engine just idling.

 

Today I did a data log recording with the engine at full operating temperature and all seemed normal. After about 60 seconds i get a solid green LED on the LC-2 and the AFR trace goes to 13.2:1 AFR which is what I programed for closed loop operation. I tried disconnecting the output from the LC-2 to the ECU and the mixture goes very rich and stays rich at 11.6:1 but all seems well during a test ride as in no tendency to misfire or surge. It is interesting that this condition occurs during the time the LC-2 is not sending O2 information to the ECU for that 60 seconds after engine start and during this time period the AFR is very rich. Too much of a coincidence maybe?

Edited by JamesW
Link to comment

Hi Jim, Set up your LC-2 to log AFR before you hit the starter, then start the bike and log the next few minutes. Email it to me and I'll take a look.

 

How many miles on the bike since you've installed the EV-14 injectors?

 

Also, the EV-14 injectors may have exceeded the Motronic's Adaptation range in the low rpm, low engine load range.

Edited by roger 04 rt
Link to comment

Morning James

 

 

 

Hmmmm....That's an interesting thought and I don't have an answer. I could easily test the air temp sensor.--The BMW AIT (Intake Temperature Sensor) seldom if ever fail as they are about bulletproof. If you have a problem with seeing incorrect IAT sensor input it is usually due to the harness terminals where they snap over the sensor terminals. If it goes open then the Motronic pretty well defaults to a 68°-70° substitution so even a failed sensor connection shouldn't effect hot start. (now the oil temp sensor is a different thing & that could easily effect hot start but normally would THEN also effect a cold start & general runability)

 

I thought about it and if this were the case then the condition I described wouldn't correct itself within the first 30 to 60 seconds after engine start with the engine just idling.--This (the delay) is probably due to the o2 sensor taking that long to come on-line.

 

Today I did a data log recording with the engine at full operating temperature and all seemed normal. After about 60 seconds i get a solid green LED on the LC-2 and the AFR trace goes to 13.2:1 AFR which is what I programed for closed loop operation. I tried disconnecting the output from the LC-2 to the ECU and the mixture goes very rich and stays rich at 11.6:1 but all seems well during a test ride as in no tendency to misfire or surge. It is interesting that this condition occurs during the time the LC-2 is not sending O2 information to the ECU for that 60 seconds after engine start and during this time period the AFR is very rich. Too much of a coincidence maybe?

Since you point out that this only happens on a hot start, then one might suspect that a temperature sensor is malfunctioning. --It's difficult to tell what you are dealing with here but to me it doesn't sound temperature sensor related. It sounds more like your LC-2 might be causing the Motronic to store different adaptives, or ???? I don't believe your (early) Motronic has more than 2 usable fueling maps as I don't think it came with a CCP socket & CCP so with (in harness wire) intact it will only have one fuel map selection & with that wire cut or open it will be very rich at idle unless it has an idle trim pot to lean the idle fueling out.

 

The BMW 1100/1150 boxers have both an IAT (Intake Air Sensor) in the air box & an oil temperature sensor on the engine.

 

The oil temperature sensor is the major player for fueling control with the IAT being a minor player & seldom if ever causes any problems.

Thanks. My point is that if a malfunctioning temperature sensor is indicating "cold" then the computer will compensate with a rich A/F mixture. And when the engine is warm, a rich mixture will make it somewhat harder to start. But once running, the rich mixture will be almost unnoticeable. Other factors, like the EV14 injectors, might also be exaggerating the effect of a malfunctioning sensor. Food for thought.-- A failing IAT (Intake Air Sensor) probably couldn't cause this as it has little effect (some riders are using IAT spoofers that swing the Intake Sensor input to REAL COLD & don't have hot starting problems) so that leaves the oil temperature sensor. When those fail (even a little) the rider knows it as the engine runs like crap.

 

 

Hmmmm....That's an interesting thought and I don't have an answer. I could easily test the air temp sensor. -- see above

 

I thought about it and if this were the case then the condition I described wouldn't correct itself within the first 30 to 60 seconds after engine start with the engine just idling.-- See if this coincides with the o2 sensor starting to come on line?

 

Today I did a data log recording with the engine at full operating temperature and all seemed normal. After about 60 seconds i get a solid green LED on the LC-2 and the AFR trace goes to 13.2:1 AFR which is what I programed for closed loop operation. I tried disconnecting the output from the LC-2 to the ECU and the mixture goes very rich and stays rich at 11.6:1 but all seems well during a test ride as in no tendency to misfire or surge. It is interesting that this condition occurs during the time the LC-2 is not sending O2 information to the ECU for that 60 seconds after engine start and during this time period the AFR is very rich. Too much of a coincidence maybe? --This might not be abnormal with the LC-2 forcing offset adaptives. You might PM Roger to see what he thinks as he has worked with the LC-2 on his 1150.

 

I guess bottom line-- with the LC-2 disconnected & the Motronic adaptives re-set (#5 fuse removed for 5 minutes or longer) do you STILL get the poor hot start condition. If yes then chase the sensors or fueling control, if NO then look for the LC-2 or it's forced adaptives being the cause.

 

You might also try JUST re-setting the Motronic adaptives re-set (#5 fuse removed for 5 minutes or longer) then try your hot start. If this makes the problem go away or get better then you are probably dealing with the LC-2 effect on the adaptives.

 

Is your CCP wire in the harness still intact & not cut???????

 

Link to comment

Hi Roger, On the data log it just shows very rich (11.6:1) during the first 45 seconds after engine start then goes closed loop at idle and the mixture goes to 13.2:1 and all is well if the oil temp is high enough to allow closed loop. This time of year with cool temperatures my early RS doesn't see 5 bars on the oil temp gauge during a test ride and the ECU won't go into closed loop at anything under 5 bars. The instant the temp goes 5 bars the data log shows closed loop AFR. I think the oil temp thermostat is missing on oilheads built before '97 and I also believe the thermostat is built into the oil cooler. I am thinking about buying a new oil cooler just to obtain the thermostat ($334). It is even difficult to get above 4 bars with the bike stationary in the garage with a fan blowing on the front of the bike, takes forever. I don't like to ride the bike this way with no closed loop fueling because of carbon build up caused by this over rich running. If I go for a 25 mile ride the oil temp will stay at 4 bars then if I stop and let the bike idle for maybe a minute or two the oil temp will go to 5 bars with a slight increase in idle speed and slightly smoother idle but then after a few minutes of riding the oil temp goes back to 4 bars and stays there. This is not a good situation at all so I'm going to buy the new oil cooler and then see where I am.

 

Thanks D.R. for the info on early Motronic operation and that makes sense. Re-setting the Motronic doesn't effect the problem so probably is effected by LC-2 operation and then there is this low oil temp situation which confuses the issue.

Link to comment

I may be wrong about the oil temp thermostat being an integral part of the oil cooler. It may be that one would have to change the oil cooler plumbing to add an external oil thermostat. Not fun.

Link to comment
I may be wrong about the oil temp thermostat being an integral part of the oil cooler. It may be that one would have to change the oil cooler plumbing to add an external oil thermostat. Not fun.

 

Afternoon James

 

The later oil thermostat is part of the engine oil outlet not the cooler itself.

 

Even with the later oil thermostat you probably won't get the engine oil hot enough as it still has ALL that exposed alloy crankcase to cool the oil sump. Even on the later 1100 bikes with the oil thermostat I would usually have to cover about 3/4 of the oil cooler in real cold weather & even then the oil temp wouldn't make it above 4 bars.

 

Link to comment
Hi Roger, On the data log it just shows very rich (11.6:1) during the first 45 seconds after engine start then goes closed loop at idle and the mixture goes to 13.2:1 and all is well if the oil temp is high enough to allow closed loop. This time of year with cool temperatures my early RS doesn't see 5 bars on the oil temp gauge during a test ride and the ECU won't go into closed loop at anything under 5 bars. The instant the temp goes 5 bars the data log shows closed loop AFR. I think the oil temp thermostat is missing on oilheads built before '97 and I also believe the thermostat is built into the oil cooler. I am thinking about buying a new oil cooler just to obtain the thermostat ($334). It is even difficult to get above 4 bars with the bike stationary in the garage with a fan blowing on the front of the bike, takes forever. I don't like to ride the bike this way with no closed loop fueling because of carbon build up caused by this over rich running. If I go for a 25 mile ride the oil temp will stay at 4 bars then if I stop and let the bike idle for maybe a minute or two the oil temp will go to 5 bars with a slight increase in idle speed and slightly smoother idle but then after a few minutes of riding the oil temp goes back to 4 bars and stays there. This is not a good situation at all so I'm going to buy the new oil cooler and then see where I am.

 

Thanks D.R. for the info on early Motronic operation and that makes sense. Re-setting the Motronic doesn't effect the problem so probably is effected by LC-2 operation and then there is this low oil temp situation which confuses the issue.

 

DR is on the right track with the LC-2, try the stock setup and see if the problem goes away.

 

The EV-14 injectors are making your IDLE very rich since they have a much shorter turn on time. That could be part of the problem too, if your adaptive values have run out of range to address pre-Closed-Loop warm idle.

 

Link to comment

Hi D.R., That's a very good idea covering off part of the oil cooler. If my bike can't see 5 bars on oil temp then it won't ever go closed loop and will run a rich AFR of 12.5:1 with my new EV14 injectors to makes matters worse.

 

Hi Roger, Yes, I believe you make a good point about the EV14 injectors causing the mixture at idle to be too rich which is why I am finding better smoother idle at 13.2:1 instead of 12.9:1 I used on the stock EV1 injectors and I may well try 13.4:1. I don't know what happened to my narrow band O2 sensor or I would remove the LC-2 and see what happens with my problem although before the LC-2 my bike had a very bad lean burn surge and much worse than my '04 R1150RT ever had. the LC-2 completely solved that problem. Today I powered the LC-2 direct from the battery and hot started the motorcycle numerous times with no sign of the problem. This tells me the 45 seconds it takes for the LC-2 to initialize is the cause of my issue and maybe is a result of interface with my very early 2.2 Motronic. I'm not sure anything can be done to correct the problem. I found out a new 2.2 Motronic from BMW would cost $2300 so not going there. I don't think there is anything wrong with my Motronic but a new up to date 2.2 ECU might correct the issue but is somewhat cost prohibitive. Would be interesting to try a new one though.

Link to comment
This tells me the 45 seconds it takes for the LC-2 to initialize is the cause of my issue....

 

So, in summary, your bike runs properly when it can warm up to 5 bars, and has been running for more than 45 seconds.

 

I appreciate your sharing your experience, because I think many of us who own oilheads love our bikes, but would also like to permanently rid ourselves of the surging. And maybe get some extra performance, too.

 

I put the EV14's on my 2004 1150RT, but I went with the AF-XiED option instead of the LC-2. I kept my narrow-band O2 sensor, and found that this combination works without drama. I think you are correct to suspect that reverting to a narrow-band O2 will solve the 45-second delay problem. I see a bunch of BMW O2 sensors on ebay for less than $20. That might be a cheap fix for part of your irritation.

 

The issue with running overly rich until you get to 5 bars of oil temp is puzzling. Is that behavior imposed by the Motronic? or is it a consequence of the LC-2? Maybe you need two "programs" for the LC-2: winter and summer.

 

 

Edited by Cap
Link to comment

Hi Cap, I kind of look upon my problem as just an example of BMW idiosyncrasy. I've actually never owned a BMW that didn't have a bit of built in character. Yeah, if i had a narrow band O2 sensor I would give it a try because the EV14s have definitely improved running at leaner AFR settings which is an overall good thing. This slightly surge like running during what I think is the initialization time of the LC-2 isn't a deal breaker by no means but is just a thing of mild curiosity mostly. I'll check eBay, thanks. I moved about 3 years ago and think I lost the O2 sensor in the move.

 

One of the problems with my FJR is it lacks personality, lol..lol.. Shouldn't laugh because I'm serious. Probably why I'll always own a BMW.

Link to comment

Try one of John-The-Greek's replacement chips in the Motronic. A proper pain to fit, but it might be worth a hundred-buck punt.

He wants to know the details of your bike and whether it has the stock breathing, exhaust, etc.

Certainly turned my UK '04 Rockster into much more of a Rocket. Negligible amount of top speed, but crisper starting, no surging, faster and more constant wrist-twist response, more Kms between fill-ups.

Kushtie.

AL in s.e. Spain

Link to comment

Hi Alan, This kind of sounds like the old song that talks about a magic bus only in this case it's a chip. I go along with Roger on this in that the Motronic is adaptive and will lean the mixture over time towards 14.7:1 just the way it works. Better to go with the LC-2 or AFXIED rather than modify the Motronic, imo. Andy makes a good point when he asks to see the dyno data.

 

I would be suspicious of this chip fix because it might just prevent the Motronic from ever going closed loop and thereby interfering with adaption which i don't think is a good thing.

Edited by JamesW
Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...