Running like a sack of potatoes

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garytong

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Afternoon all knowing ones.
R1200 twincam. Over the last 50mls the bike has started running worse and worse, like it is running with an old fashioned choke on. Connected a GS911 and there are NO alarms, or abnormal parameters. The Lamda is running at maximum rich, top of the scale. All normal stuff checked (plugs,coils, air filter etc) and swopped where possible with a friends bike, no change. Whatever is the problem it is affecting BOTH cylinders
Any ideas?
Thanks in advance and promising to drink to the good health of whoever can come up with a solution.
 
garytong said:
Afternoon all knowing ones.
R1200 twincam. Over the last 50mls the bike has started running worse and worse, like it is running with an old fashioned choke on. Connected a GS911 and there are NO alarms, or abnormal parameters. The Lamda is running at maximum rich, top of the scale. All normal stuff checked (plugs,coils, air filter etc) and swopped where possible with a friends bike, no change. Whatever is the problem it is affecting BOTH cylinders
Any ideas?
Thanks in advance and promising to drink to the good health of whoever can come up with a solution.
Click to expand...

Not sure what you mean by "The Lamda is running at Maximum rich,top of the scale"
The lambda sensor should be displayed with your GSS911 as a slightly erratic sign wave oscillating between 100mv and 800mv.
If you have a straight line at say 900mv then you have found your problem.
 
Mistacat said:
Not sure what you mean by "The Lamda is running at Maximum rich,top of the scale"
The lambda sensor should be displayed with your GSS911 as a slightly erratic sign wave oscillating between 100mv and 800mv.
If you have a straight line at say 900mv then you have found your problem.
Click to expand...
Just read this and thought the same as you. But to op days both cylinders affected?

It's the op sure both cylinders definitely affected? If yes, then fuelling?

Sent from my SM-G975F using Tapatalk
 
Dont get confused by Lambda sensor as such..

Its designed to report a value based on the oxygen levels in the unburnt gases

As Mistacat rightly said if its giving a constant value would suggest the Lambda has failed

they usually fail high or low - either way its fixed value suggests something is wrong

However It seems unlikely that both would fail at the same time, which then suggests something else is wrong.

What your seeing could be related to the constant value the Lambda's are seeing as its sending a correction value back to the system

which is then responding to the erroneous lambda values


What condition are the plugs in sooty ? oily

start with the basics


Oil condition , last changed?

Air filter

Plugs

right fuel

Are the throttle body's balanced

Idle motors reset ?


ect ect
 
Also consider fuel pressure regulator which is nicely hidden under the tank and apparently cannot be tested.
Just replaced mine (about £65) and it cured my poor running problem. One of the symptoms was the constant smell of petrol whilst under load.
 
Do we get any more clues, age of bike, mileage, is it running rough at tick over, when cruising, under hard acceleration, at high revs, ???????
 
Evening Guys.
Many thanks for all your advice. It is definatly both cyclinders that are affected, equally. On the GS911, on the Lamda graph, were it shows 'weak' or 'rich' both cylinders are running ABOVE the rich line on the scale and the engine stinks as if running on choke . both cylinders are running the same temperature also, which points to it being a common problem. service interval is behind shedule, but tbh it's not an air filter issue etc. I tend to agree that it could be fuel pressure related? as I have exhausted most other avenues, coils, plugs, air filter etc.
Thanks again guys.
 
Unfortunately the fuel pressure regulator can’t be tested and up is a sealed unit but it’s relatively easy to change. Your symptoms sound like the ones I had and the regulator change cured it.
 
The fuel pressure can be tested , T off a gauge at the quick disconnect on the pump feed ( I have a 40mm gauge permanently fitted on the bike dash).
This will test pump and regulator performance. Pressure should be 3.5 bar for pre-twin cam and 4 bar for twin cam.
Also check the other things that control both cylinders.
Throttle position sensor,
Intake air temperature.
Ambient air pressure.
Engine temperature.

It would be handy if you could log the data with the GS911 and make the .CSV file available.
 
Hi Mistacat.
great list to check, thanks.
I haven't gone so deep with the GS911 yet, but I'll give it a go. :thumby:
 
Good morning Mistacat.
I have a .CSV file of the engine stationary and also running. How do I "make it available"? it would be greqt if you could run your eyes over it, but the forum won't let me upload a .CSV file. Suggestions on a postcard to..........
Cheers
 
Data .CSV file received.
Only 70 seconds of data with 30 seconds of engine running for reasons explained by the data.
What it does show is .
Air temperature sensor, Ok.
Air pressure sensor , OK.
Engine temperature compared to head temperatures, OK.
The data shows that it is being started as if it was a carburettor engine that was flooded. ( the throttle being held wide open all the time).
This will just put loads of fuel into the engine. The injector pulse width whilst the engine is running is what I would expect to see from a full throttle acceleration in 6th gear from 90 mph.
Either that or the fuel pressure is very low. ( you can only measure this with a gauge) there isn`t a sensor to report fuel pressure to the ecu. It is mechanical.
If you are NOT holding the throttle wide open as reported by the data. Check the throttle position sensor using GS911 --- real time data.
It should go from 0 to 100.01 % smoothly as the twist grip is rotated.
From the short snippet the lambda sensors look ok ,but the data set was taken with a cold engine and full throttle keeping it in open loop.
First I would disconnect the battery for a few minutes then reconnect it, just to reboot the ecu just in case there is a glitch there.
Then check the throttle position sensor.
An English version of the data would have been easier than this French version, but have worked around it.
 
If he has not been giving it full throttle to record the data then it looks like the wiper in the TPS has come adrift or a short in the TPS wiring.
I have used the Hella ones that Santa has listed from ebay, and they have been good.
They are 43K ohm. I purchased a couple of random TPS units from China for another project and they turned out to be the same impedance.
 
When mine started to fail, i cleaned it and better then normal service was resumed

i replaced it with the Hella one and there was no difference ie the same (all good)

i held onto the original cleaned one as backup -

not sure if i still have it when i cleared out the hexhead stuff,

i'm dues some farkling days over then next few weeks, so will check just in case

For the bike to run rich, is it getting a correct air temp value, or has a spoofer been fitted at some time to ""improve"" fuelling
 
Air temperature is correct.
Throttle position between 87.7 % and 100.01 %
The injector pulse width is around 12 m/s

I will send you a copy of the data.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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