K11 Owners Group

kengibson · Posted: Thu Sep 11, 2008 7:46 pm Post subject: New Sudden Death puzzle

I know this forum already has many discussions of Sudden Death causes and fixes but I've read them all and tried most or all of the fixes and my sudden death has only gotten worse. The good news is that it is now very consistent and the symptoms are pretty consistent:

- Happens on a warm day soon after the water temperature passes the half-way mark. Almost always happens. Won't happen on a cool morning.
- Won't happen when sitting idling and hot. Seems to only happen when the engine is under load although has died when going downhill.
- The engine completely cuts out (no cylinders fire). In some cases it cuts out completely for several seconds. The bike just slows to a stop with the engine turning over driven by the rear wheel, but not firing.
- In some cases it cuts in and out but when it's out, no ignition. When it cuts back in, or when I restart it, blows clouds of smoke out the exhaust.
- Dashboard lights, headlight, tail-light, etc. stay on.
- Always starts back up in a minute or two.

The smoke SEEMS to indicate the injectors are firing fuel into the cylinders but there is no ignition (my guess).

Things I have done:
- Took it to the dealer to read the motronic code - nothing. No stored codes.
- Cleaned and re-seated every connector I can find;
- Replaced fuel pump and filter (needed that anyway);
- Swapped HES;
- Swapped Throttle Position Sensor;
- Bypassed the sidestand switch;
- Revved the engine when hot, in the dark to look for arcing from the coils or spark-plug wires - nothing;
- played with the kill switch while rolling down the road, dead - no effect.
- Verified a good ground connection from the coils.
- Measured spark plug wire resistance and verified secure connections.
- Visually inspected every wire I can find as well as the coils and spark plug wires.
- Has new spark plugs.

None of the above has had any effect at all.

I have not bypassed the kill switch but the failure so strongly correlates to engine temperature I think it's unlikely. Also, as described above, I've played with it while rolling down the road with the engine dead

What have I missed?

Thanks for the ideas.

Roy S. · Posted: Thu Sep 11, 2008 8:11 pm Post subject:

What make, year and model are you referring to?
_________________
1993 K1100LT/On going project
1990 K75rt
1991 K75s
LURKER at LARGE

kengibson · Posted: Thu Sep 11, 2008 9:24 pm Post subject:

Oh right, '95 K1100RS

/Ken

DaveVoorhis · Posted: Thu Sep 11, 2008 9:31 pm Post subject:

My 93 has a separate ignition amplifier that can fail, which takes out the ignition. I vaguely recall that the later models integrate this into the Motronic unit. Might be worth trying another Motronic to see if that cures it.

The tank connector that supplies power to the fuel pump can corrode and cause the fuel pump to stop intermittently. Clean it with a dental pick or whatever and pack it with grease.
_________________
'93 K1100RS
Dave #3

kengibson · Posted: Thu Sep 11, 2008 9:45 pm Post subject:

Aha. That explains why I couldn't find it. The '93 factory repair manual shows it (calling it the Ignition Output Stage) but it doesn't exist on my '95.

Good clue. Thanks.

Flying Duck · Posted: Thu Sep 11, 2008 9:52 pm Post subject:

Some WAGs: (which you might have alreayd pursued

Fuel tank connector. Not likely given symptoms but who knows.

Load shedding relay? Swap it with one of the other black relays.

Make sure the main ground bolt under the tank is tight.

(PS: For future posts it makes life easier for you and us if you list your model, year and maybe approx mileage in your signature.)
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

kengibson · Posted: Fri Sep 12, 2008 12:18 am Post subject:

OK. how's this?
_________________
'95 K1100RS with only 47k miles

Jim · Posted: Fri Sep 12, 2008 9:20 am Post subject:

that's good - now you need to fix your avatar...
_________________
Jim
1997 K1100LTSE 94,000 - still has gremlins!
1995 R100RT Classic 16,650 crashed - repaired!
1992 K75RTP 46,000

"We shall not all die, but we shall all be changed."

Roger Jacobsen · Posted: Fri Sep 12, 2008 5:48 pm Post subject: Sudden Death

I also have a 95 K1100, I had what sounds like the same problem occur. Occasionally the engine would just die while riding. After a few to quite a few seconds it would refire and would run fine for a hour or a day. Really makes you question the reliability of your bike until it's fixed and runs good for a while and your confidence returns. It turned out to be a coolant high temp sensor that was going bad. Had it replaced and has been fine since. You might have it checked. Good Luck!!
_________________
Jollyroger
1995 K1100LT

Tim (Midland Section) · Posted: Fri Sep 12, 2008 6:22 pm Post subject: Re: Sudden Death

burdog · Joined: 09 Jul 2006 Posts: 12 Location: Brisbane

folks,
I to have a K1100lt 95 model with 142k on the speedo, recently she has been exhibiting similar tendencies, namley a perfect temperment when cool (night running or nil traffic) and when things get hot ie the temp gauge gets to say half way and three quaters, and either stay's there or gets cooler she will just quit Shocked

sometimes without complaint sometimes with a lot of carring on, in all cases (so far Embarassed

) she will restart if left alone for a minute or so.
i have taken her apart and to a couple of mechanics, and the best idea is a ignition problem, (also suggested was boiling the fuel in the lines...) i have changed the spark plugs (overdue) and replaced the radiator fluid, i'm going to take her in and swap out the part they suggested tomorrow and see if that helps....

acftfliehr · Big Brick Rider Joined: 05 Nov 2007 Posts: 62

Hmmm Vapor lock in the fuel lines....

With the alcohol in the fuel now, (sometimes up to 10% which is scandelous) vapor lock is an increasing concern.

Auto Gas STC's (FAA Approvals) in light aircraft do not allow auto gas with alcohol in any amounts due to this reason and also its effect on certian rubbers and sealers...

Johnny Blanket install would probably help this issue....

kengibson · Posted: Thu Sep 18, 2008 8:48 pm Post subject:

I ruled out the water temp sensor as the cause of my problem. You can see my diagnostic setup at the link below. I disconnected the water temp sensor at the connector on the left side of the frame. I put my portable multimeter in the map pocket of my tank back and and connected it to the sensor. Then I put a 1k Ohm resistor in the motronic side of the connector to fool it into thinking the engine was at a normal operating temp. Then I rode around with this setup on a warm afternoon.

The resistance of the sensor showed a nice linear decrease from 2.5k Ohms to around 200 Ohms as the engine warmed up.

Meanwhile, the engine experienced the same sudden-death symptoms.

I think I've confirmed it's the ignition amplifier (Output Stage as BMW calls it). Unfortunately, since I have a post '93 model, it's integrated in the Moronic unit so I have to replace that whole thing.

_________________
'95 K1100RS with only 47k miles

kengibson

From: "eBay Member"
Date: November 3, 2008 6:05:42 PM MST
To: kenjgibson
Subject: Good news. eBay item #200268508868 95 BMW K1100LT K1100RS K1100 CDI MOTRONIC ignition box

Dear kenjgibson,
You are the winning buyer for the item below. Thank you for your business!
PLEASE READ ALL OF THE FOLLOWING IMPORTANT INFORMATION!!!
Item title: 95 BMW K1100LT K1100RS K1100 CDI MOTRONIC ignition box
Item number: 200268508868
Buyer User ID: kenjgibson

Your total is:
$170.50 per item
_________________
'95 K1100RS with only 47k miles

fnord · Posted: Fri Nov 07, 2008 5:31 pm Post subject:

Well, when does it get installed?
_________________
1993 K1100RS
1999 Jeep Wrangler

WVMSFKRS · Posted: Fri Nov 07, 2008 5:50 pm Post subject:

Just wondering, is that a new unit? If not how would you know if was good?
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IBA#42211
MSF Rider Coach
Riders Edge Instructor
'09 K1200LT
'07 K1200GT Traded
'96 K1100 RS SE *SOLD*
'05 HD Ultra 82,000+ miles
'04 URAL *SOLD*

jr'sbmw · Big Brick Rider Joined: 04 Nov 2008 Posts: 54 Location: Fl

Relating to vapor lock. I have fuel pressure guages on both my K100RT and K1100LT. Years ago, my RT drove me nuts with stalling when the gas tank got hot after running a couple of hours. The fuel psi gauge told me it was a fuel problem with low pressure. When I put cool fuel back in from a fuel can, it ran fine again!!!! I replaced the worn fuel pump and the problem was solved.

lrome48 · Posted: Sat Nov 08, 2008 9:40 pm Post subject:

Not one mention of the TPS. I had the same problem. I disconnected all major connectors, Motronic, TPS, temp sensor etc..., cleaned them and filled them with dielctric grease. Bike has not skipped a beat since. For me it was the TPS connector, but cleaning all of them and sealing them is just good PM. My 2 bits.
_________________
Larry
K75
97 K1100 LT Specialk under construction
87 SpecialK75 Carols done!
2004 K12 Special the 'Beast' delivered
K1100 Standard Custom Gone but not forgotten

kengibson · Posted: Tue Nov 11, 2008 4:26 pm Post subject:

The bike is pretty well torn apart for an overhaul over the winter. Step one is to replace the almost 14 year-old brake lines with a braided steel kit from Spiegler. After that, comes the clutch.

I expect to get it back together and try out the replacement Motronic around early March.
_________________
'95 K1100RS with only 47k miles

kengibson · Posted: Sat Sep 12, 2009 11:34 am Post subject: It's done!

Hi all,

I know I've been ignoring you and am WAY overdue to post a summary of how this problem turned out. When I left you back in November I was having thoughts of giving up on the K1100 and buying a new bike. After looking at a few new ones, I decided instead to make the RS my winter project. I tore it down to pretty much just the engine with the frame on top.

Here's a picture from last January:

Here is a list of the things I did. I'm probably forgetting a few things:

Clean and rebuild brake calipers (front and back);
New brake pads (front and rear);
Braided steel brake lines;
Duck Smith LED kit;
New rear view mirror clips;
Add mirror tethers;
Rebuild hand brake to eliminate buzzing;
New dash, front brake fluid cover, choke switch cover, hand grips;
New rubber trim/gaskets on kneeboards;
Manic salamander bar-end weights;
New clutch cable;
New throttle cable;
Valve check (all good);
New clutch;
Clean and lube all splines with Honda MolyLube 60;
Clean and treat rubber covers at front and back of drive shaft;
Re-paint ABS tray, battery tray, side-stand, center-stand (Rustoleum rattle-can);
Repaint rear fender with Bumper-black;
Side case covers painted flat black at local body shop ($120);
Clean and inspect Starter and Alternator;
Replaced all the fluids;

To address the electrical problem:
Clean, inspect and armour-all condition all wiring harness insulation;
Clean treat, and inspect coils and related wiring;
Clean and re-seat virtually every electrical connector including fuses, spark-plug wires, ground connections;

I also cleaned many bolt heads and aluminum parts with a brass brush and generally cleaned parts as I put it back together.

The result is the electrical problem is gone and it looks and rides like a new bike with both the old and new Moronic units. Even though I had checked many of the electrical connectors last year, one of them was causing the problem and is now fixed.

I've been too busy this summer to do a lot of riding but got out for an overnight ride to southwest Colorado two weekends ago. Here's a picture near Lake City:

So this story has a happy ending and I have a reliable RS that looks like new. Thanks to everyone who has posted advice in this forum. I couldn't have done it without all the help.
_________________
'95 K1100RS with only 47k miles