K11 Owners Group

Mike d · Posted: Thu Mar 19, 2015 7:08 am Post subject: 1997 K1100 Running Rough

This is to help another BMW Club UK member.

1997 K1100LT, bought on a whim!

The bike starts easily and at idle sounds perfect.

Go for a spin and it starts to run rough (on 3 cylinders). each time it seems to be number 4 plug fouled up/flooded.

Jobs performs so far:

Compression check - Good
It has a new fuel pump and fuel filter.
The injectors were checked and showed to have a similar spray pattern.
Throttle bodies balanced.
Fuel pressure checked and seems o.k.
New plugs fitted.
Replacement plug leads & coils (from my known good K1100)
Replaced TPS (From my known good K1100)
ECU swapped out (as above)
Electrical connections to ECU, coil etc. checked and cleaned (but not found to be bad anyway.
The Hall sensor has been changed and ignition retimed (on the original the timing was out). Since then the old hall sensor has been refitted with no improvement.
I have measured the resistance of the coolant sensor from the ECU cable connector. This is different pins to the K100, but all seemed o.k.

I have requested he check the valve clearances, and swap over the injector from number 4.

Any more ideas?

Mike

SugarHillCTD · Posted: Thu Mar 19, 2015 7:22 am Post subject:

I have had some strange engine behavior when a ground wire was loose- the thick ones that attach engine to frame, etc. Probably a long shot in this case since it seems to affect cylinder #4 but something to look for.

This is a tough one.
_________________
John & Cathy

'92 K100RS4V Pearl White SOLD
'04 K1200GT
IBA Several-SS1k, BBG, 50CC NYC to S.F.

Scott_Anderson · Posted: Thu Mar 19, 2015 7:36 am Post subject:

If cyl #1 plug isn't showing any signs of fouling/misfire, then it's probably not electrical related(primary ignition anyway) as cyl 1 and cyl 4 share the same coil pack.
Though if you are looking for anything to try, you could swap the coil's.

I'm thinking a valve clearance issue though.

My step daughter had an occasional misfire on a single cyl on her Honda(CRV car), and found that the valves were out of spec. Adjusted the clearance and no more misfire.(side note-Honda recommends checking valve clearances every 15K miles on that engine......)
_________________
Ride safe.

1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

552255 · Posted: Thu Mar 19, 2015 8:59 am Post subject:

Maybe check for throttle body leaks at the lower riser that sits on top of the engine block, or anything above.? My '97 ran much better after replacing the rubber bits down there, and cleaning up the throttle body units, fuel lines, vacuum hoses, etc.

But if your cylinder isnt even firing per se, this advice is somewhat irrelavant!...electrical gremlins are no fun. The 'ground' connections on these bikes can seem finicky...
_________________
1997 K1100LT-SE
1996 K1100RS-SE
"Black & Silver Duo"
Lincoln, NE

Mike d · Posted: Thu Mar 19, 2015 3:38 pm Post subject:

Hi,

Thanks for the suggestions.

SugerHillCTD : earths have been carefully inspected, removed and cleaned. (one of the first checks as I am aware of the age of the bike and the importance of the connections).

Scott: I didn't think the oil pack swap would make a difference, but wanted to definitely exclude it from the investigation, so both packs were changed for my own known good ones.

Waiting for feedback on the valve clearances....

552255: Yes checks for air leaks have been made (should have been in the list).

The cylinder fires up and the bike idles perfectly, just plays up when ridden.

Keep the ideas flowing, I will not let it beat me!

Mike

Mike d · Posted: Sat Apr 04, 2015 12:12 pm Post subject:

O.k. so time for an update.

The #2 inlet valve - cyl 1 (working from the front of the bike) is tight at 0.08mm.

The #5 exhaust valve - cylinder 3 is loose at 0.38mm

All other clearances are within spec.

Now if the problem had been valves on cylinder 4 I would be more happy, but at least this is the first hard fault we have found!.

He hasn't as yet swapped over the injector electrical connections or the injectors themselves (I did ask him to do this before checking the valves).

So, knowing a valve is tight, but only one of the two on a different cylinder to that which was suspect, could this be the actual fault.?

Mike

Scott_Anderson · Posted: Sat Apr 04, 2015 12:47 pm Post subject:

Mike d · Posted: Sun Apr 05, 2015 6:34 am Post subject:

Hi Scott,

Scott_Anderson · Posted: Sun Apr 05, 2015 9:45 am Post subject:

You mentioned in the opening post that the compression check was good.
By chance do you know the compression numbers?
What oil is he running in it.
What plugs did he put in it.
_________________
Ride safe.

1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

Mike d · Posted: Sun Apr 05, 2015 11:48 am Post subject:

H Scott,

I'll double check with him on the numbers etc.

Can't remember the plugs he used, but they were replaced with new ones of the correct grade. They have also been swapped from cylinder 4 to others.

Not sure when he will be able to look at the bike, but hopefully this week.

Mike

tmarshall57 · Posted: Thu Apr 09, 2015 9:05 am Post subject:

I had identical symptoms with similar evidence (oiled up plug on one cylinder). The spark plugs were fairly new so were last on my list. The culprit was a prematurely failed plug.
_________________
K1100RS Special Edition 1997
Arctic Silver/Black

Mike d · Posted: Thu Apr 09, 2015 5:59 pm Post subject:

Thanks, I'll double check, but am sure he swapped the new plugs around to eliminate that.

Mike

rgscomp · Posted: Fri Apr 10, 2015 3:43 am Post subject:

I would also check the injectors...
On my K1100 the symptoms were all plugs black and sooty but it turned out to be a faulty injector. I assume that because one cylinder with faulty injector was very rich and not sparking much the ECU was putting more fuel through the others to try and keep engine going. So as all plugs were black/sooty I didn't suspect an injector but a more systemwide fault affecting all 4 cylinders.

I wiggling the No. 1 injector a bit and thats when I found the problem. Secondhand injector and all OK since...
Bike would idle sort of OK but poor fuel consumption and didn't run great.

Mike d · Posted: Fri Apr 10, 2015 2:38 pm Post subject:

Thanks RGSCOMP, however with this bike it is only a single cylinder fail, which doesn't cause the others to run rich.

Not heard back from him recently, but know he has been out riding one of his other bikes a fair bit in the unusually fine UK weather Very Happy

Mike