Jump to content

Help with r1200c hard start


Giddy

Recommended Posts

I've been fighting this bike for over a year with this same issue. Every morning I have to hold the throttle open and hold the starter until my bike finally starts. I've done plugs, plug wires, new injectors, new fuel lines, new fuel strainer, new fuel filter, new air filter, new HAL, new relays and finally a new o2 sensor. I'm at a complete loss. I've been asking on chromeheads for help, but no one has ideas past a vacuum leak or bad plugs.

 

The bike will (maybe) start, die a few times, finally start enough to get moving, die at the first few stop signs, then after about a mile all is fine. It's not 100%, but it isn't rough and won't die at idle. For the rest of the day the bike will start fine with no additional throttle.

 

Please any help would be appreciated.

 

The fuel pressure regulator and battery were going to be my next things to change. At this point I'm just slowly building a new bike piece by piece trying to find the problem.

 

Link to comment
19 minutes ago, Giddy said:

Would that be the oiltemp sensor? I know it has oil temp and air intake sensors.

Morning  Giddy

 

To get a decent cold start both the oil temp sensor & the AIT (Air Intake Sensor) must input the correct ambient & engine temperature & be somewhat in agreement. 

 

You need to verify that both are working & registering correctly. 

 

Another place to look is at the cold start fuel flow & pressure, low (engine cranking) fuel pressure or low fuel flow during cold start can make cold starting a hit or miss deal. 

 

Any idea on what you battery voltage is during cold engine cranking? (if much below 10v that can also cause cold starting issues.

 

What year 1200C are you working with as those have an unusual fueling control system vs other boxer twins of that era, we need to pin the year down if we can.   

Link to comment

Thank you for the reply! It's a 2003 normal r1200c.

I've pulled the injectors and watched them at cold start and they seemed fine. The battery is very old and while it seems to turn the starter fine, I know that dropping voltage can cause problems. Since I have to pull the tank I'll probably buy a battery since I've been putting it off. 

 

I do have a Booster Plug on this bike, I was thinking about pulling it off and trying the air intake sensor without it. 

 

Is there a way to check the sensors? Or are they too sensitive for a multi meter test?

 

I rode the bike for 3 years almost daily before this developed, now it's been a year of changing one thing at a time and trying it the next day.

Link to comment
41 minutes ago, Giddy said:

Thank you for the reply! It's a 2003 normal r1200c.

I've pulled the injectors and watched them at cold start and they seemed fine. The battery is very old and while it seems to turn the starter fine, I know that dropping voltage can cause problems. Since I have to pull the tank I'll probably buy a battery since I've been putting it off. 

 

I do have a Booster Plug on this bike, I was thinking about pulling it off and trying the air intake sensor without it. 

 

Is there a way to check the sensors? Or are they too sensitive for a multi meter test?

 

I rode the bike for 3 years almost daily before this developed, now it's been a year of changing one thing at a time and trying it the next day.

Afternoon Giddy

 

Definitely remove the booster plug as a test, those things can cause issues on cold starting under some conditions.

 

If you have a volt meter put that across the battery posts then see what your cold cranking voltage is, that alone might point a finger at your problem.

 

You can test both your intake air sensor & your oil temperature sensor with an ohm meter, the resistance will not be linear from cold to hot but it will tell you if they are working.  Put the sensor in the freezer overnight, then remove & hook up your ohmmeter, then see if the resistance changes smoothly in relation to the temperature increase. 

  • Thanks 1
Link to comment

Thank you! Maybe there is hope for this old oilhead! 

 

I'm going to check the sensors and replace the battery. Am I looking for any specific range of resistance? Or just that it does change with temperature 

Link to comment
1 hour ago, Giddy said:

Thank you! Maybe there is hope for this old oilhead! 

 

I'm going to check the sensors and replace the battery. Am I looking for any specific range of resistance? Or just that it does change with temperature 

Afternoon

 

 The BMW 1100/1150/1200c uses a negative temperature coefficient (NTC) thermistor for sensors. Those things are not a linear output sensor as far as ohms per degree goes. 

 

The colder the sensor is the higher the resistance so just look for a drop in resistance as the sensor warms up & that there are no holes or opens in your resistance readings as sensor warms up from cold. 

  • Thanks 1
Link to comment

Just one more question that I'm sure sounds stupid. 

I'm guessing when I pull the coolent sensor I will of course lose a lot of oil. Should I go ahead and order a filter and just drain the oil and do an oil change while I test the sensors?

 

 

Link to comment
10 minutes ago, Giddy said:

Just one more question that I'm sure sounds stupid. 

I'm guessing when I pull the coolent sensor I will of course lose a lot of oil. Should I go ahead and order a filter and just drain the oil and do an oil change while I test the sensors?

 

 

Afternoon  Giddy

 

There are no stupid questions on this web site! Just ask away.

 

You won't lose much, if any,  oil (especially if you allow the motorcycle to sit overnight before removing the oil temp sensor) as the oil temp sensor sits way up high on top of the oil thermostat. 

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...