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1Back to top Go down   Misfiring cylinder 2 and 3. Empty Misfiring cylinder 2 and 3. Wed Jul 20, 2016 7:16 pm

ChocolateFrog

ChocolateFrog
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Hello all.

I've recently purchased (19th) a 1987 k100 that's only running on 2 cylinders. I've been doing a fair bit of swatting up on the 'flying brick' but still have lots to learn. I'm reasonably mechanically minded but my electrical knowledge could be better. 

I've seen there are a few threads on here already regarding misfires but they don't seem to relate exactly to what I have. Hopefully once the cure is found this thread might help a fellow K owner in the future.

Situation so far. The bike runs but only on cylinders 1 and 4 (looking at the head L to R). Max speed is 60 mph and it will not go over 4000rpm. 

What I've done. Checked plugs (changed by previous owner) as expected 1 and 4 look ok, 2 and 3 wet and black. They're NGK's so I've ordered some original bosch ones as I read somewhere they may be better. There is spark to all plugs but it seems weak but that could have been the intensity of the sun today.

HT leads checked. Also look to be in good condition, resistance on all 4 looks as it should.

Coils. Replaced by former keeper for known good ones. Resistances are as they should be visually they look good. No witness marks on the crankcase to see.

Its got a recent AGM battery looks almost as big as the one in my car.

Cleaned up the main earth point under the tank it had grease on it which I think may have been insulating it (not sure if bad?) 

Checked outputs from the EFI under tank all seems good. 

Hall sensors are getting power and ground. Haven't been able to test them bit they've also been replaced by the prevuous owner. 

Removed and cleaned the AFM. The flap moves freely, visually the factory seal is still intact and the resistance across the temp sensor is correct. 

Checked for obvious vac leaks, hoses I can see all look ok.

Checked the fuel filter was not blocked and is installed the correct way round.

Lastly the choke light stays on permanently and the cable is slack despit being on the end of its adjustment, not sure what's going on there.

I'll put it back together tomorrow to see if I've cured it but if not any other ideas? I'm getting near the limit of my knowledge. 

Cheers

Paul

    

2Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Wed Jul 20, 2016 8:02 pm

Holister

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The unit under the tank is the ICU (ignition). The FICU (fuel injection) is under the seat.
The ignition fires in pairs. 1+4 and 2+3. The two coils are marked accordingly. 1+4 coil is the front one.
It seems that you are either not getting a pulse for the 2+3 coil or the coil is not generating the HT required to fire the SPs sufficiently.
A problem we've seen a few times is that the ICU plug becomes partly dislodged. There is no clip on this plug, just a rubber boot, so sometimes it can work loose.
Check that the 2+3 coil's earth connection is properly connected.
Go to the Portal tab and click on the trouble shooting link if you haven't already.
Be careful testing your HES. They are easily fried.
Hope this helps.
cheers


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  Misfiring cylinder 2 and 3. Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

3Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Wed Jul 20, 2016 9:27 pm

Crazy Frog

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What about swapping the coils to see if the problem shifts to cylinders 2 and 3?
This would rule in or out a deffective coil....
Easy to do and no money to spend Smile


__________________________________________________
Misfiring cylinder 2 and 3. Frog15Misfiring cylinder 2 and 3. Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

4Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 5:09 am

92KK 84WW Olaf

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As Crazy Frog says, swap the coils because cylinder 2 and 3 share the same coil. The K uses a wasted spark so both cylinders 2 and 3 are firing at the same time. When swapping coils just make sure the electrical connections to them are all good and clean.

Just a thought, unlikely enough one though, if that still throws up no running on 2 and 3 run a compression check on them.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 37,190 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 miles.

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

5Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 6:23 am

ChocolateFrog

ChocolateFrog
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@Holister wrote:The unit under the tank is the ICU (ignition). The FICU (fuel injection) is under the seat.
The ignition fires in pairs. 1+4 and 2+3. The two coils are marked accordingly. 1+4 coil is the front one.
It seems that you are either not getting a pulse for the 2+3 coil or the coil is not generating the HT required to fire the SPs sufficiently.
A problem we've seen a few times is that the ICU plug becomes partly dislodged. There is no clip on this plug, just a rubber boot, so sometimes it can work loose.
Check that the 2+3 coil's earth connection is properly connected.
Go to the Portal tab and click on the trouble shooting link if you haven't already.
Be careful testing your HES. They are easily fried.
Hope this helps.
cheers
Thanks. I did notice there was no clip on the plug under the tank and the boot was partially dislodged. I'm keeping fingers crossed when I put it back together it might work.

    

6Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 6:26 am

ChocolateFrog

ChocolateFrog
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@92KK 84WW Olaf wrote:As Crazy Frog says, swap the coils because cylinder 2 and 3 share the same coil. The K uses a wasted spark so both cylinders 2 and 3 are firing at the same time. When swapping coils just make sure the electrical connections to them are all good and clean.

Just a thought, unlikely enough one though, if that still throws up no running on 2 and 3 run a compression check on them.
Thanks. I will do a compression test,  haven't got my gauge with me unfortunately. The previous owner who seemed like a very genuine guy said the compression was all good.

    

7Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 10:18 am

ChocolateFrog

ChocolateFrog
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Put it all back together and no joy. It might habe run on 3 for a minute but definitely now on 2 I can touch the headers on 2 and 3 while it's running.

I swapped the coils over and no change so they're both definitely working.

What's the best way of checking the low tension side of the wiring?

    

8Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 10:58 am

ChocolateFrog

ChocolateFrog
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Checked the voltage across the LT wires and both coils are seeing 12v.

Swapped 2 and 3 HT leads onto 1 and 4 and they still run so all HT leads are good.

Removed spark plugs, cleaned and swapped them around 2 into 1 and 3 into 4 same result so all the plugs are working.

Regards

    

9Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 11:07 am

Crazy Frog

Crazy Frog
admin
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You said that you swapped the leads, but did you swapped the coil itself?
One coil could be deffective.

Are the spark plugs on cylinder 2 & 3 wet after trying to run the engine?


__________________________________________________
Misfiring cylinder 2 and 3. Frog15Misfiring cylinder 2 and 3. Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

10Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 4:10 pm

ChocolateFrog

ChocolateFrog
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@Crazy Frog wrote:You said that you swapped the leads, but did you swapped the coil itself?
One coil could be deffective.

Are the spark plugs on cylinder 2 & 3 wet after trying to run the engine?
I did both independently. The 2/3 coil powered cyls 1 and 4 happily. Likewise when I later swapped the leads.

Spark plugs in 2/3 look wet when I pulled them. 

Theres no oil in the water or mayo on the oil cap so im not suspecting HG failure yet.

I need to work out if the ecu is seeing the signal from the hall effect sensors and if so is it cutting the voltage to the coil. After that I'm out of ideas.

    

11Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 4:56 pm

Crazy Frog

Crazy Frog
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When you remove spark plugs 2/3 and you try starting the bike (plugs touching the ground), do you get a spark on these plugs?


__________________________________________________
Misfiring cylinder 2 and 3. Frog15Misfiring cylinder 2 and 3. Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

12Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 5:19 pm

ChocolateFrog

ChocolateFrog
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@Crazy Frog wrote:When you remove spark plugs 2/3 and you try starting the bike (plugs touching the ground), do you get a spark on these plugs?
Yes but it seems weak.

I just been out and done another test. Ignition on bike in 5th gear and I manually rotated the rear wheel. The fuel pump primed approximately every 8th of a wheel turn. 

Does that suggest the ECU is seeing a signal from the HES? 

Had to give up after that as im at the OH house and the bike is in the street, I'll be getting some funny looks. If (big if) it is electrical then I think I've narrowed it down to the ignition module. 

Do these tend to fail?

    

13Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 5:33 pm

92KK 84WW Olaf

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Connectors/connections are a far bigger fail than the modules themselves. Cleaning the pins and refitting the plug can cure a lot.

When you did the coils independently did you run the engine with them swapped? As in the 2/3 coil ran 2/4 ok, but did the 1/4 coil run cylinder 2/3 ok at the same time?

You could have a dodgy connection meaning that one of the two hall effect sensor [HES] signals is compromised. The HES wire comes up behind the radiator and connects onto a plug connector under the fuel tank. The HES if I am correct gives a signal twice on a complete rotations, one for 1/4 and another for 2/3.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 37,190 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 miles.

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

14Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 5:47 pm

ChocolateFrog

ChocolateFrog
active member
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@92KK 84WW Olaf wrote:Connectors/connections are a far bigger fail than the modules themselves. Cleaning the pins and refitting the plug can cure a lot.

When you did the coils independently did you run the engine with them swapped? As in the 2/3 coil ran 2/4 ok, but did the 1/4 coil run cylinder 2/3 ok at the same time?

You could have a dodgy connection meaning that one of the two hall effect sensor [HES] signals is compromised. The HES wire comes up behind the radiator and connects onto a plug connector under the fuel tank. The HES if I am correct gives a signal twice on a complete rotations, one for 1/4 and another for 2/3.
To answer your questions.

I've cleaned up all the connections I can find, I've gone through nearly a full can of contact cleaner, nothing seemed too bad, no green fur on any of the connectors.

Yes I ran the engine and only 1 and 4 fired when the coils were swapped.

I'm coming to the conclusion like you say that the output from the sensor is not reaching the 2/3 coil(if the sensor is working). I'm going to take the tank off again tomorrow and check the ecu for signal going in (pin 5 and 13) and leaving to coils (pin 9 and 14).

I'm also assuming those pins should have continuity with pin 1 the ground?

Thanks for all the help thus far, feel like the possibilities are being whittled down slowly.

    

15Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 5:56 pm

92KK 84WW Olaf

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Do check that connector coming from the HES. Its got more than 2 wires. The route from the HES under the rad and up the right side of the frame could have some damage. The connector to the loom is worth cleaning. I think one of those pins will be 1/4 and another 2/3. The other ends are up at the ICU as you mention.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 37,190 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 miles.

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

16Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 6:03 pm

ChocolateFrog

ChocolateFrog
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@92KK 84WW Olaf wrote:Do check that connector coming from the HES. Its got more than 2 wires. The route from the HES under the rad and up the right side of the frame could have some damage. The connector to the loom is worth cleaning. I think one of those pins will be 1/4 and another 2/3. The other ends are up at the ICU as you mention.

Yes I've checked it and it all looks ok. The connector seats ok and I've removed the cover plate on the engine, the sensor itself is spotless.

It's a 5 pin plug. Pin 1 is shielding, 3 and 5 are power and ground pins 2 and 5 are the signal wires. I've read 2 is the top sensor and 5 is the bottom, not sure which coil they correspond to. I'll hopefully find out tomorrow.

    

17Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 6:51 pm

Crazy Frog

Crazy Frog
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@ChocolateFrog wrote:
If (big if) it is electrical then I think I've narrowed it down to the ignition module. 

Do these tend to fail?
Yes they do fail Shocked
A couple of weeks ago, I was helping a fellow Canuck troubleshooting his problem and we found that the ignition module was defective.


__________________________________________________
Misfiring cylinder 2 and 3. Frog15Misfiring cylinder 2 and 3. Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

18Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 6:55 pm

ChocolateFrog

ChocolateFrog
active member
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@Crazy Frog wrote:
@ChocolateFrog wrote:
If (big if) it is electrical then I think I've narrowed it down to the ignition module. 

Do these tend to fail?
Yes they do fail Shocked
A couple of weeks ago, I was helping a fellow Canuck troubleshooting his problem and we found that the ignition module was defective.
Worryingly I've just reread the ebay ad for the bike and the previous owner has already replaced the hall sensor and ignition module. Theyre not guaranteed to be good either I suppose.

    

19Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 10:12 pm

92KK 84WW Olaf

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If its any consolation I found that connecting the replacement Hall Sensor to the loom socket needs a little care. Worth checking that routing and the connections. I found there was very little slack in the cable and found it needed care to avoid having a pull on the plug connection. The pins on that may need cleaning, mine did.

From what you are finding its also possible the problem arises from one of the sensors or one of the signal wires being damaged or else further along the trail.

Have you a means of swapping an ignition module for a test? Anyone near you with one on a shelf?


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 37,190 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 miles.

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

20Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 21, 2016 11:14 pm

kennybob

kennybob
Silver member
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Try to run it a night in the dark and see if there is sparking and arc around the coils and wires--the wires may look okay on the outside, but electrically leak.

if the HES tests out okay then there is little left but the harness and the ECU.

There are a couple of big transistors in the ECU that switch the current for the ignition coils.  It may be that the 2&3 device has a broken solder joint on the board.  i have repaired hundreds of Motronic units that had a defective solder joint on the ignition transistor.

    

21Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Fri Jul 22, 2016 4:56 am

ChocolateFrog

ChocolateFrog
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@92KK 84WW Olaf wrote:
Have you a means of swapping an ignition module for a test? Anyone near you with one on a shelf?

Not that I'm aware of. There's a couple reasonably priced on ebay at the moment.

    

22Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Fri Jul 22, 2016 9:58 am

ChocolateFrog

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Does anyone know how to open up the ignition module. I've undone the 12 screws but don't want to force anything apart that shouldnt be pulled apart

    

23Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Fri Jul 22, 2016 11:04 am

ChocolateFrog

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Think I've found something!  One of the Hall sensors has a scrape on the sensor surface. See pic. That could well be my problem, thoughts?

Edit dont seem to be able to upload pics.

    

24Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Thu Jul 28, 2016 3:17 pm

ChocolateFrog

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I've been away all week but got home to find a parcel on the side. Opened it to find a replacement Hall sensor from Motoworks. 

Unfortunately this one looks in worse condition than mine, one sensor is all scratched on the surface and the backing plate is very rusty. 

Not impressed. I don't even want to put it on the bike. Going to call Motoworks in the morning and see what they say.

    

25Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Fri Jul 29, 2016 1:06 pm

ChocolateFrog

ChocolateFrog
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Well the new sensor and ignition module have made no difference.

Starting to run out of ideas now. Will do a compression test tomorrow but after that I'm pretty stumped.

    

26Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Fri Jul 29, 2016 6:38 pm

KJustin

KJustin
Silver member
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I had the same problem a few months back (though it was 1-4 not firing in my case).  I can't help with troubleshooting more than what's been said above, but thought I'd lend moral support.  I really do feel your pain.  I'm a pretty patient person, but I was on the verge of giving up and parting out the bike.  No joke.  

For what it's worth, I replaced both coils, the HES, the plug wires and also the starter relay (after welding it because my battery ran down during testing), my battery (which I killed when the welded relay made the engine crank until battery death) and the ICU (because I used a non-OEM starter relay as a replacement that did not have a snubber circuit, which ended up frying my ICU).  Not to mention that I also pulled and cleaned my starter.  If you look around on the forum, I had 3 or 4 long threads documenting all that I went through.

Anyway, my problem ended up being that the ICU plug was dirty (which I discovered before the non-OEM starter relay fried my ICU).  I sprayed both sides of the ICU plu/socket down with Deoxit and all was well after that.  I know that you did this, and others above advised about it, but I wanted to mention it again since I've had problems with it twice now--once with it being dirty and once with it being knocked partially loose because there's no clip.  

Best of luck.  Hope you get it sorted soon!


__________________________________________________
1985 K100 Cafe Racer (formerly an RT), VIN 0051736
    

27Back to top Go down   Misfiring cylinder 2 and 3. Empty A little too late? Sat Jul 30, 2016 9:52 pm

Cablebeacher

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Hi all

Been busy so only looking this morning 'cause I need some info...

As a real latecomer to this problem can I ask if you have got the HT leads in the correct order?

Problem for newcomers (yes I did it) is that the HT leads go against common sense: they are NOT simply 1234 in order of length of lead.

Sorry I can't find my service manual at the moment but I think the last two leads go differently to what you think by looking at them i.e. last shortest one is actually 2nd last. There are also numbers printed on the HT leads but can be a little hard to find if they are at all dirty.

Hope this helps...

Mal

    

28Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Sun Jul 31, 2016 10:22 am

92KK 84WW Olaf

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I did wonder that about the leads, and yes they do most definitely NOT go in order of length. I think its 2 and 3 go opposite way around and no 3 cylinder loops around no 2. There is a wasted spark but if 2 and 3 are at 180 degrees to each other this may affect the firing as the sparks would occur at bottom instead of top dead centre. But a problem like this would result in zero firing at all on 2/3.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 37,190 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 miles.

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

29Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Sun Jul 31, 2016 11:49 am

kennybob

kennybob
Silver member
Silver member
i had a friend with a similar issue that turned out to be the coils.  Worked/weak spark at idle and low revs, but couldn't sustain high rpms.

Did you ever do the in-the-dark test with the coil cover removed to see if there was arcing between the plug wires and the end of coils?

If you swapped out the ICU and had same results it seems hard to believe both could be bad in the same exact way, but it could happen.

For troubleshooting i would pull all 4 plugs and ground their bases securely to the bike with ends exposed.  You may need to make a fixture of sorts to hold the plugs and wrap copper wire around the threads to create the ground path, etc.  Then crank it over and observe if 2-3 has spark or is noticeably weaker than 1-4.  Then swap just the control wire to the coils such that the 1-4 control wire is running to the 2-3 coil, and repeat the test and observe the spark pattern.   This test could help rule out the HES and the ICU and narrow it down to the harness, coils or plug wires.

    

30Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Sun Jul 31, 2016 5:03 pm

AL-58

AL-58
Life time member
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I did lose 2 cylinders on my sidecar when it still had the 2v engine fitted.  My first thought was coils so I replaced the coil for the 2 cyls not functioning with no effect.  Further investigation led me to find the low tension wires for that coil had chafed and earthed on the engine block.  Fixed the wiring and all was OK.

Al


__________________________________________________
'87 K100RS/HRD sidecar (1100 motor)  sc25 

'87 K100RT with Paralever backend

"When I'm too old and too foolish to handle a sidecar I'll buy a Sportsbike"

Misfiring cylinder 2 and 3. K-dogs10
    

31Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Sun Jul 31, 2016 6:34 pm

ChocolateFrog

ChocolateFrog
active member
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@Cablebeacher wrote:Hi all

Been busy so only looking this morning 'cause I need some info...

As a real latecomer to this problem can I ask if you have got the HT leads in the correct order?

Problem for newcomers (yes I did it) is that the HT leads go against common sense: they are NOT simply 1234 in order of length of lead.

Sorry I can't find my service manual at the moment but I think the last two leads go differently to what you think by looking at them i.e. last shortest one is actually 2nd last. There are also numbers printed on the HT leads but can be a little hard to find if they are at all dirty.

Hope this helps...

Mal

The HT leads are numbered as are the HT outputs on the coils. I'm 99% sure they're correct but a photo of someone else's would be good to confirm. Cheers.

    

32Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Sun Jul 31, 2016 6:36 pm

ChocolateFrog

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@92KK 84WW Olaf wrote:I did wonder that about the leads, and yes they do most definitely NOT go in order of length. I think its 2 and 3 go opposite way around and no 3 cylinder loops around no 2. There is a wasted spark but if 2 and 3 are at 180 degrees to each other this may affect the firing as the sparks would occur at bottom instead of top dead centre. But a problem like this would result in zero firing at all on 2/3.

It would be very embarrassing if this was the case.

    

33Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Sun Jul 31, 2016 6:41 pm

ChocolateFrog

ChocolateFrog
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I've stripped down the intake system. The rubber components looked worse for wear, several cracks but no obvious leaks. Also the injectors had atleast 3 different brands of O rings on so I've sent them for a refurb.

    

34Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Sun Jul 31, 2016 6:57 pm

Holister

Holister
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@kennybob wrote:i had a friend with a similar issue that turned out to be the coils.  Worked/weak spark at idle and low revs, but couldn't sustain high rpms.

Did you ever do the in-the-dark test with the coil cover removed to see if there was arcing between the plug wires and the end of coils?

If you swapped out the ICU and had same results it seems hard to believe both could be bad in the same exact way, but it could happen.

For troubleshooting i would pull all 4 plugs and ground their bases securely to the bike with ends exposed.  You may need to make a fixture of sorts to hold the plugs and wrap copper wire around the threads to create the ground path, etc.  Then crank it over and observe if 2-3 has spark or is noticeably weaker than 1-4.  Then swap just the control wire to the coils such that the 1-4 control wire is running to the 2-3 coil, and repeat the test and observe the spark pattern.   This test could help rule out the HES and the ICU and narrow it down to the harness, coils or plug wires.
I’d have to agree. Everything points to the 2+3 coil and that test would be worth doing.

I would also check the impedance on both coils. Primary should read about 2.5Ω and secondary around 10 to 12 kΩ



HT leads should measure 5 kΩ

All this info is available on the 'Troubleshooting Page' on the Portal tab.


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  Misfiring cylinder 2 and 3. Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

35Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Sun Jul 31, 2016 7:01 pm

ChocolateFrog

ChocolateFrog
active member
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@Holister wrote:
@kennybob wrote:i had a friend with a similar issue that turned out to be the coils.  Worked/weak spark at idle and low revs, but couldn't sustain high rpms.

Did you ever do the in-the-dark test with the coil cover removed to see if there was arcing between the plug wires and the end of coils?

If you swapped out the ICU and had same results it seems hard to believe both could be bad in the same exact way, but it could happen.

For troubleshooting i would pull all 4 plugs and ground their bases securely to the bike with ends exposed.  You may need to make a fixture of sorts to hold the plugs and wrap copper wire around the threads to create the ground path, etc.  Then crank it over and observe if 2-3 has spark or is noticeably weaker than 1-4.  Then swap just the control wire to the coils such that the 1-4 control wire is running to the 2-3 coil, and repeat the test and observe the spark pattern.   This test could help rule out the HES and the ICU and narrow it down to the harness, coils or plug wires.
I’d have to agree. Everything points to the 2+3 coil and that test would be worth doing.

I would also check the impedance on both coils. Primary should read about 2.5Ω and secondary around 10 to 12 kΩ



HT leads should measure 5 kΩ

All this info is available on the 'Troubleshooting Page' on the Portal tab.

I've checked both coils, I've swapped them round to no effect. I.e both coils are definitely working, likewise the 2 and 3 leads work perfectly in place of 1 and 4 leads. 

I am now wondering if the 2/3 coil is marked up incorrectly and the ht leads are the wrong way round.

    

36Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Mon Aug 01, 2016 6:12 am

Holister

Holister
Life time member
Life time member
I am now wondering if the 2/3 coil is marked up incorrectly and the ht leads are the wrong way round.
2 and 3 both fire at the same time off the one coil. I don't think it would matter which way round those leads were but it would if you mixed either one up with 1 or 4.


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  Misfiring cylinder 2 and 3. Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

37Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Mon Aug 01, 2016 11:28 am

kennybob

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Silver member
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Seems like it is pointing to the control wire in the harness between the ICU and the 2/3 coil, hence my suggestion to swap the control wires to see if the problem follows the swap and also rules out most everything else...

Swapping out the coils and testing at idle only is not a valid test due to the high frequency breakdown character of insulation.

    

38Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Mon Aug 01, 2016 5:15 pm

ChocolateFrog

ChocolateFrog
active member
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@Holister wrote:
I am now wondering if the 2/3 coil is marked up incorrectly and the ht leads are the wrong way round.
2 and 3 both fire at the same time off the one coil. I don't think it would matter which way round those leads were but it would if you mixed either one up with 1 or 4.

This was my thinking. Can can anyone confirm 100% that it doesn't matter which way round the leads go as long as 1 and 4 go to the front coil and 2/3 go to the rear coil.

    

39Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Mon Aug 01, 2016 5:17 pm

ChocolateFrog

ChocolateFrog
active member
active member
@kennybob wrote:Seems like it is pointing to the control wire in the harness between the ICU and the 2/3 coil, hence my suggestion to swap the control wires to see if the problem follows the swap and also rules out most everything else...

Swapping out the coils and testing at idle only is not a valid test due to the high frequency breakdown character of insulation.
They've all got continuity and I've visually inspected them all, I don't think it's the wiring.

    

40Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Sat Aug 06, 2016 11:13 am

ChocolateFrog

ChocolateFrog
active member
active member
FIXED

Finally! It was either injectors or the the rubbers between head and throttle body or between throttle body and plenum.

Or a combination of all 3. 

Choke seems to have seized on so my idle is at about 3000 rpm but otherwise fixed

    

41Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Sat Aug 06, 2016 12:18 pm

kennybob

kennybob
Silver member
Silver member
Did you pull and test the injectors on the rail, or clean the injectors, or how did you go from chasing an ignition problem to solving a fuel problem--that's a long stretch away when troubleshooting and it might help the next guy down the road...

    

42Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Tue Aug 09, 2016 4:59 pm

ChocolateFrog

ChocolateFrog
active member
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@kennybob wrote:Did you pull and test the injectors on the rail, or clean the injectors, or how did you go from chasing an ignition problem to solving a fuel problem--that's a long stretch away when troubleshooting and it might help the next guy down the road...

I pulled the injectors and sent them off to be ultrasonically cleaned, they also replaced the filters and o rings.

basically i had gone through the whole electrical system and either checked or replaced everything down to wiring and connectors, there was nothing left to test. therefore i turned to the fueling, tested the pump, replaced the fuel filter, checked the pressure regulator and various vac lines.

It seems it was just coincidence that it was injector 2 and 3 that was playing up leading to the wild goose chase on the electrical side.

    

43Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Tue Aug 09, 2016 5:49 pm

Dai

Dai
Life time member
Life time member
@ChocolateFrog wrote:Choke seems to have seized on so my idle is at about 3000 rpm but otherwise fixed
If you've had the throttlebodies/plenum chamber off then it's a good bet that the throttle is jammed against one or more of the jubilee clips. We've all done it (or most us anyway!) Very Happy


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

44Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Wed Aug 10, 2016 4:51 am

92KK 84WW Olaf

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@Dai wrote:
@ChocolateFrog wrote:Choke seems to have seized on so my idle is at about 3000 rpm but otherwise fixed
If you've had the throttlebodies/plenum chamber off then it's a good bet that the throttle is jammed against one or more of the jubilee clips. We've all done it (or most us anyway!) Very Happy

I had that on the LT. A PO had done it and I found one of the clips interfered with the throttle mechanism preventing it from returning to rest position. I was able to sort it by loosening the clips and rotating them enough.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 37,190 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 miles.

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

45Back to top Go down   Misfiring cylinder 2 and 3. Empty Re: Misfiring cylinder 2 and 3. Fri Aug 12, 2016 6:30 pm

ChocolateFrog

ChocolateFrog
active member
active member
@92KK 84WW Olaf wrote:
@Dai wrote:
@ChocolateFrog wrote:Choke seems to have seized on so my idle is at about 3000 rpm but otherwise fixed
If you've had the throttlebodies/plenum chamber off then it's a good bet that the throttle is jammed against one or more of the jubilee clips. We've all done it (or most us anyway!) Very Happy

I had that on the LT. A PO had done it and I found one of the clips interfered with the throttle mechanism preventing it from returning to rest position. I was able to sort it by loosening the clips and rotating them enough.

It was corrosion it's seized solid so I've removed it for the time being. I won't be riding it in cold weather anyway.

    

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