K11 Owners Group

[N0rseman]

Hi all,

I've been trouble shooting an engine probem. I think I've narrowed it down to cylindare number 4 not fireing. I further think that it is the Ignition coil. My manuale says "BMW does not provide any test prodedures or restance values for checking the primary and secondary side... have it tested by a BMW dealer using a spard gap tester".

I can hold on the the wire on cylindare 4 and to a certain extent 3 but for 1 and 2 the spark in much more intence. My guess is that the coil on 4 is low and that 3 is going. But at over $200 for a new part (12131459890) I would realy like to test it first. My local shop's machanic is out and the other one is over 1 hour away (one way).

Idea's or suggestion of how to test my Ignition coils?

Thanks

1993 k1100lt.
-Paul
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1993 k1100 LT

[whyoldbill]

Paul,
Static testing of coils isn't really going to tell you a whole lot anyway, but your primary coils should have pretty low resistance using a DC Ohm meter (less than 1 ohm). From one Primary side to the Secondary where either spark plug wire connects should be wide open. Between the 2 secondary connectors should be around 13kohms.
Your coils could show all of these readings perfectly and still be bad, if the insulation is breaking down under high voltage... Which is why BMW doesn't provide test procedures.
I hope this helps at least a little.

Bill
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'02 - GL1800


The desired effect is what you get when you improve your interplanetary funksmanship - George Clinton

[Phil Marvin]

Hi,
If cylinder #4 is not firing, I doubt it is the coil. K1100 ignition systems use 2 coils. One coil fires 2 cylinders, so if you don't have problems with 2 cylinders, it probably isn't the coil. It could be your ignition wire, cap, spark plug, cap loose on the plug, or a number of other things, but I doubt it is the coil.
_________________
Ride Safe,
Phil Marvin in El Paso, TX
'94 K75A/3
'95 K75RTP

[N0rseman]

Hello Phil and Bill and thank you for your advice.

Phill at over $400 for two new ones, I too hope that it is not the coil. I'll walk though your list and see what else it might be. I have already: replaces the plugs,
switched out the fuel injector on #4
new fuel filter,
new air filter,
checked the valves clearances.

But the old girl sounds more like Chitty Chitty Bang Bang then her old self. I can take #4 out and it sounds no different.

I was saddened by the cost of new coils but heartened when I though I'd might have finally found the problem.

I'll keep at it...
_________________
1993 k1100 LT

[wedge]

Swap leads and see if it affects a different cylinder
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Bikes:
93 K75S
93 R1100RS

[N0rseman]

It's not the wires. I switch the wires for cylinder 3 and 4. Yet #4 is still dead.

What I know of ignition is the simple Air, Fuel Spark formula. I know that I can barely hold on to the wires for cylinder 1 or 2 when the starter is pressed. but # 3 is manageable and 4 is just a tickle. Are the secondary coils noticeably weaker then the primary ones? It's my guess that the secondary coil for 3 is going and that 4 is gone.

I think the next step is to take these ignition coils in and see if the BMW shop can bench test them.

Please chime in if you have alternative suggestions.
Thanks
-Paul
_________________
1993 k1100 LT

[whyoldbill]

Paul,
Check your private messages/
_________________
'02 - GL1800


The desired effect is what you get when you improve your interplanetary funksmanship - George Clinton

[Scott_Anderson]

I would swap the coil packs, 1/2 with 3/4 and see what happens. If the coil is bad you will have problems then with 1/2.

How is your compression with #4.

I had a problem with my '97 with cyl 2 and 3 and thought it was head gasket only to find out I burned 2 valves at the same time.
_________________
Ride safe.



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