Cylinder 2 cold

650 Views 24 Replies 14 Participants Last post by Capt howdy, 3 d ago

ErikGuldberg

Discussion Starter · 12 d ago

I have a pretty consistent problem with cylinder number 2 on my K1200GT (K44) from 2007, and I would really appreciate some inputs.

The exhaust ports on cylinders 1,3 and 4 all reach around 450F (230C) when the engine is warm and running, but the exhaust port on number 2 only reaches around 250F (120C). I have spent a month trying to locate the error, and I have gotten nowhere.
I have replaced, gapped and tested all spark plugs.
I have checked compression and I get the same reading on all 4 cylinders (125 psi but the tool is probably not calibrated).
I have checked valve clearance and all cylinders are equal and within specs.
I have checked that all spark plugs are firing when the engine is cranked. Spark is consistent and seems strong on all cylinders.
I have tested functionality of all four fuel injectors (off the bike) and spraypatterns look fine. I have replaced the injector on cylinder number 2 to eliminate that completely as the cause of the problem.
I have replaced the ignition coils on cylinder numbers 2, 3 and 4 with new, original ones (the one on cylinder 1 was replaced a few years back and I thought that the other three might be heading towards retirement as well).
I have replaced all rubber boots between the air filter housing and the throttle assembly and ones between the throttle assembly and the engine(engine revved up, when carb cleaner was sprayed at the boots, so there was a false air issue).
I have inspected all plugs, connectors and wires visually for damage.
I have bought an OBD tester (UniCarScan UCSI-2100) and the MotoScan app ("Ultimate" license version) from WGsoft, and I have no error codes on any sensors.
I can activate the injectors individually through the app and they all sound the same when activated. None of them drops out or changes "rhythm" when activated.

Now I am at the point, where I can not really find anything more to test except chasing after a non consistent electrical issue around the ignition coil or the injector on cylinder number 2 - or something with the ECU.

Has anybody in here ever experienced a similar issue? Or does anybody have any idea for further tests, I could perform in order to isolate the problem to one component?

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leaton10

· #21 · 8 d ago

ErikGuldberg said:
I have a pretty consistent problem with cylinder number 2 on my K1200GT (K44) from 2007, and I would really appreciate some inputs.

The exhaust ports on cylinders 1,3 and 4 all reach around 450F (230C) when the engine is warm and running, but the exhaust port on number 2 only reaches around 250F (120C). I have spent a month trying to locate the error, and I have gotten nowhere.
I have replaced, gapped and tested all spark plugs.
I have checked compression and I get the same reading on all 4 cylinders (125 psi but the tool is probably not calibrated).
I have checked valve clearance and all cylinders are equal and within specs.
I have checked that all spark plugs are firing when the engine is cranked. Spark is consistent and seems strong on all cylinders.
I have tested functionality of all four fuel injectors (off the bike) and spraypatterns look fine. I have replaced the injector on cylinder number 2 to eliminate that completely as the cause of the problem.
I have replaced the ignition coils on cylinder numbers 2, 3 and 4 with new, original ones (the one on cylinder 1 was replaced a few years back and I thought that the other three might be heading towards retirement as well).
I have replaced all rubber boots between the air filter housing and the throttle assembly and ones between the throttle assembly and the engine(engine revved up, when carb cleaner was sprayed at the boots, so there was a false air issue).
I have inspected all plugs, connectors and wires visually for damage.
I have bought an OBD tester (UniCarScan UCSI-2100) and the MotoScan app ("Ultimate" license version) from WGsoft, and I have no error codes on any sensors.
I can activate the injectors individually through the app and they all sound the same when activated. None of them drops out or changes "rhythm" when activated.

Now I am at the point, where I can not really find anything more to test except chasing after a non consistent electrical issue around the ignition coil or the injector on cylinder number 2 - or something with the ECU.

Has anybody in here ever experienced a similar issue? Or does anybody have any idea for further tests, I could perform in order to isolate the problem to one component?

It seems that you have checked all the things that would be obvious, so my first thought was something not so obvious. I know next to nothing about this bike. But having said that, if it's like most, it has a separate exhaust pipe for each cylinder and you are measuring the temperatures there. Soooo - could it be that there is a thermal conduction difference between the colder pipe and the others? Maybe it's not tight against the cylinder port similar to the others? Or maybe it's more tight. Maybe the others have a mating gasket and this one doesn't. If the pipe has better thermal conductivity to the exhaust port on the head, it would probably run cooler, wouldn't you think?
Another thought, maybe there is more exhaust back pressure on that cylinder.

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cobbler

· #22 · 7 d ago

Change out the O2 sensor, you can find inexpensive used ones on eBay.

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Honolulu

· #23 · 3 d ago

A GS-911 will map the O2 sensor output voltage. It should swing up and down in regular fashion at idle. Other inexpensive diagnostic software packages may do the same thing for much less than GS-911 charges for their little box.

When my 2010 K13 ran obviously very rich, the GS-911 was no help at all b/c I couldn't find the correct range of mapped variables. Turned out the bike was overfueling b/c a fuel pressure sensor had failed telling the ECU that fuel pressure was low, resulting in longer duty cycles for all injectors. I think GS-911 can measure fuel pressure but little does it matter if 1) you don't know what correct pressure is or 2) whether or how it's supposed to vary with engine load. I still don't.

Whatever is wrong with one cylinder, and fuel pressure isn't likely to be it. I post only to fill in possible gap in general knowledge.

Is ISTA-D (which BMW uses for car diagnostics) is functional on Kbikes? I have not heard of it being used. That software is available, though interface, installation and proper configuration are challenges. Not to hijack, but such use if appropriate, could be our future.

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botus

· #24 · 3 d ago

yes, but diagnostic info is really basic on this model

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Capt howdy

· #25 · 3 d ago (Edited)

This is a shot in the dark in the event that all else fails
The crankshaft sensor continuously determines the time in which a certain number of teeth of the increment gear run past the sensor. These segment times are constantly checked during engine operation. In the event of a fault, a fault code is stored in the fault code memory and the fuel injection is deactivated at the relevant cylinder. This is usually initiated by engine misfires but is a faulty crankshaft sensor sending false signals perhaps. I'm not even sure that the bike has the ability to cut off the FI. And a GS911 I think would detect such a fault. As I say - just guessing here.

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