Author Topic: Running on one cylinder (Read 3187 times)

Juvecu · « **on:** June 25, 2012, 15:54:23 »

I missed the MAG Hands off EU ride this Sunday because I had to troubleshoot a problem with the bike and I'm very pissed off about it.

Took the week off to rest and do some work around the house and on the bike. The main thing I did was to sort out my valve clearances. All the exhaust valves were too tight, one had no clearance at all. They are all in spec now. Put the bike back together and it ran fine the Saturday night, started it Sunday morning and it was running on 1 cylinder intermittently. The problem seems to be only with the rear cylinder. I've previously had the bike stuttering and running on 1 cylinder for a few seconds at a time, but this is much more permanent and it stutters almost all the time. It certainly makes filtering on the M40 and A404 interesting...

I've previously tested the coils as per the manual and they tested in spec, but I must say I'm not too confident in a simple test like that. I cut the tip off each coil lead and screwed the spark suppressor caps back in to them to make sure the connection is good. I also swapped the front and rear caps around, the problem stays with the rear cylinder. The way I know it stays with the rear is by unplugging the rear spark plug lead when the bike idles on one cylinder, it just keeps running without change. If I unplug the front it dies. The rear lead sparks and I can't see/hear any breaks in this at idle. I've changed the plugs before when I had the stutter previously.

I've also opened the valve covers again and made sure the timing is correct. I did this because I thought I might have accidentally set the rear cylinder to spark on the exhaust stroke rather than the compression stroke, but it was correct. The problem is intermittent and if it works the bike runs well which is another indication that the timing is correct.

I've checked all connections as best as I could, but I didn't test every wire involved. I'm looking for some pointers on what to check. I'm wondering if it's perhaps an injector or an injector wire so I've dug out the testing procedure for that and will do it this weekend (I don't have proper tools to work on it where I stay in the week.)

It completely slipped my mind to swap the coils around, I will do that when I get home tonight. If the problem moves to the front cylinder I will know it's a coil issue. I'm hoping that it's something as simple as that.

Any help/suggestions would be appreciated at this point.

greywolf · « **Reply #1 on:** June 25, 2012, 16:25:38 »

There have been a few cases of the injector wires developing corrosion at a crimp joint. You can see if that is your problem by checking the yellow/red wire on the rear injector for power. It should be hot whenever the ignition is on and there is no CHEC at the clock position.

Locky · « **Reply #2 on:** June 25, 2012, 17:26:03 »

After reading half way through your post , I was wondering why there was no mention of swapping the coils over ....Then I got to the end of the post !
Greywolfs suggestion sounds credible , and they would have been disturbed when you had the throttle boddies off .

FragglePete · « **Reply #3 on:** June 25, 2012, 20:30:43 »

How strange, I'm experiecing exact same issue.

Picked it up from a full on service on Saturday and all seemed fine (including having the valve clearances checked) and this morning on my way to work the revs just suddenly went to 3k RPM with the throttle closed and sat there. Wound it down, but just running rough, cut out a couple of times and really non-responsive. Took it back to the workshop where they said it was only running on one cylinder! Amazing how it'll still run along the M4 at a fair chat on just one!!! :D

It's in with the workshop, and I've moaned and muttered about it being alright before they got their grubby little hands on it. Hopefully find out tomorrow what the issue is and that 'this better not cost anything more than I just spent with you'...

Will update when I know.

Pete

Juvecu · « **Reply #4 on:** June 25, 2012, 23:06:15 »

I swapped the coils and it made no difference. I don't have a tester with me, but I'll check if I can drop in on Keith. I think you're right Greywolf, those wires are what I have to check next.

greywolf · « **Reply #5 on:** June 26, 2012, 01:38:15 »

If you don't have a tester, you can jumper the Y/R wires on each injector together and see if that works.

Juvecu · « **Reply #6 on:** June 27, 2012, 10:16:03 »

Keith lend me a tester, he dropped it off this morning so I will have a look tonight.

The bike is now running on one cylinder with the other one constantly cutting in and out (sometimes several times per second.) If I can't get it fixed in the next 2 days I'm considering disconnecting the rear cylinder's injector wire and riding it home the 92 miles on 1 cylinder. At least it won't be jerking around all the way and I'd avoid the backfiring too.

I'll see what I find tonight when I get home, I'm hopeful.

Juvecu · « **Reply #7 on:** June 28, 2012, 13:15:02 »

Thanks to Keith I had the use of a multimeter and I set about doing checks last night. I couldn't find any problems with the injector wiring at all. The voltages were proper and the connections between the connector and the ECU connector are all good. In fact, I took the connectors that plug into the injectors apart and the spades are spotless. No tarnish on them at all and the copper cable in the crimp looks like new. The rubber seals and the heat from the engine must keep the moist out well. I ran the bike and wiggled wires for several minutes and I just couldn't get any reaction from it so I'm now sure it's not a wiring issue.

Unfortunately this means it's either the injector or the ECU. I have a spare injectors at home that I can test with, but I'm starting to think it is the ECU even though I'm not usually one to think they cause problems. I need someone near with a K4-K6 bike that I can plug my ECU into to check it. Anyone around either Reading or Warwick/Leamington Spa?

For now I have disconnected the rear injector. The bike runs on the front cylinder only without any stutter at all. It's obviously down on power a lot, but it's safer that way than getting the constant surging.

Strommer · « **Reply #8 on:** June 28, 2012, 13:46:47 »

Someone has just posted up a restricted one in the For Sale. Wouldn't have to be a full power one for testing.

If you're in Ealing over the next few days you can pop in and borrow mine.

Juvecu · « **Reply #9 on:** June 29, 2012, 15:24:08 »

Can't seem to find anyone near me to help with the test so I might have to take you up on that. I'll let you know if I can't organise anything else.

Juvecu · « **Reply #10 on:** June 29, 2012, 15:35:59 »

longman is going to send me his ECU for testing on Monday so I'm sorted

FragglePete · « **Reply #11 on:** June 29, 2012, 21:43:59 »

Got mine back yesterday, the workshop baffled by what happened. The throttle sync just went wayout on mine. All sorted now though and all seems good. Sorry, can't be more help.

Pete

Keith Cross · « **Reply #12 on:** July 03, 2012, 21:49:52 »

Ant update on this mate, are you sorted OK?

Keith C

Keith Cross · « **Reply #13 on:** July 07, 2012, 09:53:20 »

Bump

Keith C

Juvecu · « **Reply #14 on:** August 10, 2012, 13:13:10 »

Managed to sort this out 2 weekends ago. Think I posted about it somewhere else, but can't remember where.

The rear injector positive wire first had a bad connection and then completely disconnected. When it completely disconnected I was able to troubleshoot and find the problem much easier than before with an intermittent connection. The positive wires on each injector is always on when the ignition is on and the ground wire is the one that get switched in and out to fire the injectors. The positive wires connect together somewhere in the wiring loom. According to Greywolf this is a crimp connector and he's seen cases where it's corroded and given problems. I took things apart and opened the wiring loom and searched for the crimp connector, but couldn't find it. In the end I resorted to stripping the insulation off the wires near the injectors and connecting the two positive wires together so the rear injector gets power again.

Running a little rough now because the throttle bodies are far out, but I will sort that when I have time again.

mr_diver · « **Reply #15 on:** February 02, 2013, 17:45:08 »

I know this problem was fixed a while back Juvecu.

I just had the exact same problem in my bike but affecting the front cylinder.

Greywolf is correct (as always) the crimp connection is crap in the loom. water gets in and sits there due to the angle of the loom at that point.

all the + wires are crimped in one place in the loom. approx inline with the rear edge of the rear cylinder.
If yours was as bad as mine you might be having the problem again. as I unwrapped the crimp the injector end came away in the tape. I poked the crimp with a screw driver and it crumbled to bits.

it's a faff to get to the section affected but well worth giving it some attention. I think we were both lucky to still have one cylinder running. could quite easily fail on both.
I know your doing some serious motorway miles and I'd personally advise you to get to and sort out the crimp.

Juvecu · « **Reply #16 on:** February 04, 2013, 18:50:05 »

Thanks for the reply mate, I'm planning on doing all these little things when I get a 2nd bike that I can use for the daily (now much shorter) commute. Either that or I will spend some time on it in summer when the light is still good until late, I like working in natural light, or my eyes do, at least.

mr_diver · « **Reply #17 on:** February 04, 2013, 18:58:16 »

I've got a cracking little project for you mate as a second bike...

or a deauville that honestly does work!

Juvecu · « **Reply #18 on:** February 06, 2013, 22:26:43 »

You're joking, but with the new job I might actually have time for a project. The trouble now is that I won't have the space for it. I forgot about the space issue so will have to rethink the 2nd bike thing for now :(

Edit: Maybe we should arrange for me to come visit you some weekend so I can help you with the CX? What still needs doing?

mr_diver · « **Reply #19 on:** February 06, 2013, 22:37:49 »

it's pretty much in the same state as in the pic, but the engine's by the door now.
I was planning on doing work to it in my 2 weeks off but so far with faffing with the deauville and sorting the wiring issues on the wee, my work on the Cx had gone out the window.

most likely on friday the deauville will be gone and replaced with a Suzuki 125 Marauder for the mrs. so my attention will be focused on getting the required chrome bits ordered and fitted to that. the CX looks like it'll be a long term project as life is getting busy again. I've got a pile of bits saved on my ebay basket to order when needed.
she will run again this year but I'll be a while yet. when she's running I'l give her a blast and visit... might even take her on a Stromtrek sometime