Fault Code 2343

[Jnclem]

I have a new to me 93 K1100LT with 48,000 miles on it. It runs very well, has loads of power, and has been getting 48+ MPG. I brought it home, about 800 miles, a couple of weeks ago. On the way, it started to die if I am coming down from any RPM above about 3000, and I pull in the clutch and close the throttle completely.

If I blip the throttle even slightly after pulling in the clutch, hold the rpms with the clutch in and allow them to drop more slowly, or simply run down to 2500 or below without pulling the clutch in, the bike will drop to idle and hold it just fine. It won't do this on the center stand, only when in motion.

I found some similar symptoms in a couple of threads. Adjusting the TPS was recommended. I checked mine with a digital multimeter, and it comes in exactly at .370- perfect.

I ran codes, and I got a 2343 "mixture setting at limit." I can't find anything that tells me what to do about that. I also don't know if that means rich, lean, or what. The plugs look perfect, it idles fine, and there is no indication that it is running either rich or lean.

What does that code mean, and what should I do about it? Any other ideas?

BTW, I have not yet synced the TB's. I have a Morgan Carbtune ordered, which should be here in a week or two.

thanks

[johnny]

greetings jnclem...

an hour of work and less than $10 in supplies... exclude the simple known offenders first... here you go...

1st thing i would do is backspin starter maintenance...
2nd thing i would do is remove the motronic plug and clean all the connections...
3rd thing i would do is undo the 4 pin under tank connector and clean it up real good...
4th thing i would do is make sure my plug wires are securely on the plugs and the plugs are tight...
5th thing i would do is make sure the battery cables are clean n tightly secure at both ends...
6th thing i would do is replace the fuel filter...
7th... if still experiencing whack i would move on from there...

j o

[Jnclem]

That's good. I have already: Replaced both fuel and air filter, cleaned and tightened battery cables on a brand new battery, cleaned morticing plug, the four pin plug, and the TPS plug, but it never hurts to clean them again. I will check the spark plugs again, as I would like to see how they look on this side of my first 1000 miles on the bike. I don't know what backspin the starter means, but I'll search that.

And yes, the good thing is that just a slight adjustment in riding style, holding the throttle a bit, lets me ride the bike all I want. This is not a huge problem, I just like things to be right. I love the bike so far. It's a great, and very different, mate for my 89 GS.

Thanks for the ideas!

[johnny]

greetings...

id pull fuse 5 for a few minutes... reseat it and give it a go... that should reset your motronic... see what happens...

j o

[K75RT Keith]

Backspinning is a method of partially cleaning the starter without removing it form the bike.  K-bricks with dirty internal contacts in the starter will cause all kinds of oddities.  Believe it or not, and as these bike have been around for 30 years believe it, a dirty starter can and will cause some of the oddest problems.

[Jnclem]

I appreciate all the replies. I've done everything suggested here, even the starter clean thing, which I thought might be like being invited to go snipe hunting, but I did it anyway. The problem remains the same. The only other clue that I have is that it will not happen in the first few minutes of riding. The bike has to be at least warm enough for the needle to reach the 1/4 mark before it will die.

I also found what I believe is one of the airflow sensors, a brass fitting in the top, right, rear of the air box with a, I believe, four pin connector going to it. I cleaned that connection too.

If it's not the TPS, but the code says it is a mixture issue, I'm suspecting an airflow sensor, or a vacuum leak. But, this bike doesn't seem to have much in the way of airflow sensors. How does the motronic determine the mixture? Anyway, I'm out of ideas for now.

[Jnclem]

Is there a way to clear that code? I'd like to clear it, ride the bike a while, and see if it comes back. When I run the diagnostic, it just continues to show the 2343 code. No matter how many times I run it, it never goes to 4444.

[TimTyler]

... The only other clue that I have is that it will not happen in the first few minutes of riding. The bike has to be at least warm enough for the needle to reach the 1/4 mark before it will die.

Isn't that the telltale of a failing HES?

[TimTyler]

... it started to die if I am coming down from any RPM above about 3000, and I pull in the clutch and close the throttle completely.

If this was a 2-valve K I'd say Check the exhaust valves - they are probably too tight, but the 4-valve K's apparently never need adjusting.

[Jnclem]

... it started to die if I am coming down from any RPM above about 3000, and I pull in the clutch and close the throttle completely.

If this was a 2-valve K I'd say Check the exhaust valves - they are probably too tight, but the 4-valve K's apparently never need adjusting.

They do occasionally, but we checked them and they're all in spec. I don't know anything about Hall Effect symptoms. I always thought the bike wouldn't start if that was an issue.

[The Mighty Gryphon]

This is a long  shot, but does your bike have an O2 sensor in the muffler?  If not, you may have a mixture adjust screw attached to the relay box just above the throttle position sensor.   I don't know if it affects the fault code, but it is possible that if you have it, it could be out of adjustment.  You need an exhaust gas analyzer to make the adjustment.

[Jnclem]

... The only other clue that I have is that it will not happen in the first few minutes of riding. The bike has to be at least warm enough for the needle to reach the 1/4 mark before it will die.

Isn't that the telltale of a failing HES?

Reading up on HES issues, my problem doesn't fit. The bike always runs very strong and idles well. It simply dies under hard deceleration if the clutch is pulled in and throttle shut completely off. Its like the brain doesn't catch the descending RPM's and bring it to idle, but instead lets it die. It always starts either with the starter while still rolling, or by simply letting the clutch out. It will rev smoothly past 6000 (I haven't gone higher) and runs fine.

It's either getting the fuel supply shut down in that one situation, of a spark issue.

Next I'm going to pull and test the ignition amplifier.

[Scott_]

I posted in your other thread to check the water temp sensor. It could be starting to fail, or at least dirty connections, causing improper mixture. It has happened to others.

[johnny]

this is how you reset it...

pull fuse 5 for a few minutes... reseat it... that should reset your motronic... see what happens...

others have seen this code and reported 1) heat sink 2) oxygen sensor 3) water sensor 4) leaking rubbers 5) and of course reset and all was well again...

j o

[Jnclem]

This is a long  shot, but does your bike have an O2 sensor in the muffler?  If not, you may have a mixture adjust screw attached to the relay box just above the throttle position sensor.   I don't know if it affects the fault code, but it is possible that if you have it, it could be out of adjustment.  You need an exhaust gas analyzer to make the adjustment.

I don't have that adjustment screw.

[Jnclem]

this is how you reset it...

pull fuse 5 for a few minutes... reseat it... that should reset your motronic... see what happens...

others have seen this code and reported 1) heat sink 2) oxygen sensor 3) water sensor 4) leaking rubbers 5) and of course reset and all was well again...

j o

I had disconnected the Motronic completely once, also the negative battery cable, also had to take the whole battery out for about an hour, so the code has been cleared repeatedly. It comes back after riding. But, it just says mixture at limit. To me, all that says is that a sensor someplace is telling the motronic to make it ultra rich or lean at some moment in the ride and throwing a code. Not very helpful as far as actually finding the problem.

Is there something like an idle air control on this thing? Just a thought.

[Scott_]

This is a long  shot, but does your bike have an O2 sensor in the muffler?  If not, you may have a mixture adjust screw attached to the relay box just above the throttle position sensor.   I don't know if it affects the fault code, but it is possible that if you have it, it could be out of adjustment.  You need an exhaust gas analyzer to make the adjustment.

I don't have that adjustment screw.

Your '93 won't have that screw as it has a Motronic fuel system. Those are on the Jetronic fuel controls.

[herseyb]

"It simply dies under hard deceleration if the clutch is pulled in and throttle shut completely off. Its like the brain doesn't catch the descending RPM's and bring it to idle, but instead lets it die."

I had this exact same symptoms, and two things combined fixed it.


First was replacing the salt encrusted rubber seals in the gas tank fill cap, and the tank where those seals mated.  This kept me from leaking a lot of pressure from the tank.  This fixed 80% of it dying when I clutched in during engine braking.

The next 20% got fixed when I ran it hard through a couple tanks with seafoam in it.

On the plus side, I'm really good at starting the bike back up now....  But futzing with it when it died on the street caused a some scary distractions.

[Jnclem]

"It simply dies under hard deceleration if the clutch is pulled in and throttle shut completely off. Its like the brain doesn't catch the descending RPM's and bring it to idle, but instead lets it die."

I had this exact same symptoms, and two things combined fixed it.


First was replacing the salt encrusted rubber seals in the gas tank fill cap, and the tank where those seals mated.  This kept me from leaking a lot of pressure from the tank.  This fixed 80% of it dying when I clutched in during engine braking.

The next 20% got fixed when I ran it hard through a couple tanks with seafoam in it.

Well that's interesting. I didn't notice anything bad with the seals when we took the cap out to replace the fuel filter, but I'm not sure we really looked either. I have run some Sea foam through it, and my milage improved. But, I have no problem with the idea of running another tank through "hard." Sounds like fun! :-)

On the plus side, I'm really good at starting the bike back up now....  But futzing with it when it died on the street caused a some scary distractions.

Very interesting. We pulled the filler to replace the fuel filter, and I didn't notice any corrosion, but it would be worth another look for sure. On the trip home, I ran a couple of tanks of Sea Foam through, and noticed a significant increase in gas milage and general happiness of the bike. But, I think running another tank or two through it "hard" might be a great idea whether it helps the problem of not! :-)

[TimTyler]

... rubber seals in the gas tank fill cap, and the tank where those seals mated.  This kept me from leaking a lot of pressure from the tank. 

K tanks are not pressurized (at least not the ones I've seen). The fuel pressure starts at the fuel pump.

The fuel tank seals are there to keep water out and gas in AFAIK.

[Jnclem]

... rubber seals in the gas tank fill cap, and the tank where those seals mated.  This kept me from leaking a lot of pressure from the tank. 

K tanks are not pressurized (at least not the ones I've seen). The fuel pressure starts at the fuel pump.

The fuel tank seals are there to keep water out and gas in AFAIK.

I was thinking about this whole thing on the way home, and came to the same conclusion - what pressure? The tanks are actually vented I believe, or were at one time, to allow air in as fuel goes out. I wonder what actually made the difference. Some more sea foam and riding it hard is never a bad idea though.

[herseyb]

Well, I've only had my brick for 4K miles, so I'm not an expert.  I just know mine goes FFffssssssss when I pop the gas cap after riding it, and did a longer slower fsssssss before I put the seal on.

Could have been the seafoam.

I wonder if mine isn't venting properly then... hm....

[johnny]

greetings...

that sound is generaly the stink vent hole mights be clogged at the gass capp and perhaps the poo pipe too...

j o

[herseyb]

Thanks Johnny.  I'll put some psyllium husk in the next tank. :falldown: