running awful

[AndyRR]

Yesterday, I rode home from the beach - about 200 mi. Everything running great, as usual. Filled up at a busy gas station 140 mi from home and made it back w/o issue.

This morning I noticed one cylinder missing occasionally after startup and I figured it was just a bit cold. After about 10 mi, it's just getting worse. Idle is fine, but when I hit the gas, it sputters and backfires. The first thing that came to mind is bad gas. Doesn't really make sense as I've gone 140 miles on that tank (water sinks, right?), but I stop at the next station, fill it up w/ premium and put a half-container of Heet (like Dry-Gas)in.

After another ten miles without improvement and I make a u-turn to head home. Suddenly the bike's running great. Even pop a small wheelie when accelerating. OK, she's fine and doesn't want to go home - another u-turn and back on my way. After 15 miles of bliss she's running like crap again.

After about 80 miles she's still alternating between running fine and no good at all. Swapped out the spark plugs (just two here) cause I had some handy, but no improvement. Now I've pulled the tank and done my best to get all the gas out - not easy. There was about a 1/4 cup that I couldn't get out so I dumped some more Heet in, mixed it up a while and scooped that out. Still a tiny bit left and I put some more Heet on top of that. If there's water, I think I've done all I can do to get it out.

I checked (blew thru)the fuel filter and it isn't blocked. Sock looks clean. So tempted to put it back together tonight, but I have a job tomorrow that requires a cage and the gasket will take overnight to shrink back to shape. Kinda silly to have this all out and not replace the filter anyway (it's been 20k), so tomorrow I'll pick up a filter and gasket.

I'm think I've covered the easy stuff and maybe that'll do it. I won't know until tomorrow.

Anyone had a problem like this? Any suggestions?

[Beemeridian]

22

[jcridge]

My money is on water in the fuel, and you haven't been out since you pulled all the fuel out, see what happens when you put it all back together. Intermittent issues are hard, but if it runs good at times, it won't be something broken or missing (that would cause the condition all the time).
Seafoam, No roadster owner should be without a can or two, ten...

John

[chibbert]

I would go with water in fuel as well. It does sound like you dd everything you could to eliminate what there may be left. Good luck and keep us posted after you button her back up.

[AndyRR]

Picked up the new filter (on sale for $24!) and gasket today.

Bottom line - no luck. I left the tank out in the sun while I went to get the parts. Absolutely dry inside when I put it back together.

I'll have to try something else tomorrow. It seems to be running poorly all the time now. I think checking for vacuum leaks will be first. Then I need to think about spark. I've heard very little about coil failures on single spark models. Gonna try to find an inductive type tester that I can clamp on the wires.

Other possibilities - fuel pump? Sounds OK, but I don't have any means of testing pressure handy. Maybe I'll take off the quick connect on the pressure side and see how far it shoots when turned on. Should be amusing if nothing else. Another pair of quick connects and a tee connected to a pressure guage would be a really easy way to check pressure.

Thanks for the replies so far. The beautiful weather is killing me as I pass through it in a cage. Must fix fast.

[boxermania]

AndyRR

Based on your description, the problem seems to point at a partially restricted injector or spark issues, like the high tension wire going to ground occassionally.

The plug swap, rules out the sparkplug, the coil is the same for the two cylinders, so it rules the coil as being the source, the other cylinder appears to run correctly so it rules out the fuel pump and system pressure.

To be absolutely sure, warm the engine up and run a compression test to rule out a burned exhaust valve, but that would not make the engine run bad intermitently.

BTW, did you checked that the accelerator cable is inside the holder on the bad running cylinder?

Keep us posted

[chitownrbike]

How about the O2 sensor?

[AndyRR]

warm the engine up and run a compression test to rule out a burned exhaust valve

This had me worried as I thought I heard some increased tapping from the right side when it was runnning badly.
I did a compression test on a cold engine. I can't run it long enough to get it hot. 125 psi right - I felt pretty good about that until I checked the left - 150.

Does this indicate a problem?

[sweatmark]

Sounds like possible time to pull the heads off, a la CycleRob's de-carboning some years back.

Chance to check valves, etc.?

[boxermania]

AndyRR

The compression is 17% lower on the right cylinder, however that is not low enough not to allow the engine to run.

Suggest that you remove the plugs and remove the injector from the TB (leave it conected to the fuel suply). Get a glas container a insert the injector in the container while cranking the bike to observe the fuel spray from the injector, compare with the opposite side.

The fuel pressure at the injector should be 3 Bar or ~ 44 psi, if one can right something to measure it. That will rule out the pump/filter.

[AndyRR]

Suggest that you remove the plugs and remove the injector from the TB (leave it conected to the fuel suply). Get a glas container a insert the injector in the container while cranking the bike to observe the fuel spray from the injector, compare with the opposite side.

I was going to try that this afternoon. Looks simple to get the injector off. Just two screws. That loosened the injector, but it didn't want to come out. I pulled kinda hard, but was being a little careful. Not sure how much these injectors cost. They should just pull straight out, right?

I was hoping to put off the de-carbonization until the off-season. If I can get the injectors out and they are OK, I guess I might have to do it now...

[AndyRR]

I should probably take a peek at the cam chain tensioner too. It's the new style.

[boxermania]

AndyRR

Spray a little WD-40 at the base of the injector, after removing the holdown bolts, and rotate the injector slightly on the base. There is an o-ring that seals the injector to the base and they get kinda stuck in there.

Side to side movement and a straight pull will allow it to come out. Note: Be gentle, you don't want to break/damage the fuel supply line to the injector.

The difference in compression pressures is not, based on what you have posted, the source of your problem, so I would hold off until the present problem is resolved before moving on with a de-carbonization.

[Mr. C]

I took the experienced rider class in the spring. It was a HOT day, lots of starting / stopping. The bike ran fine all day, then half way home it started developing a serious engine vibration. Checked a few things to no avail, but it was due for the 24K service including valve adj and TB sync, so I mentioned the problem to them and dropped it off.

Well they went through it and had trouble with the synch, ended up finding the electrical connector on one of the injectors was all corroded with green crud. They cleaned it up, reconnected everything and then it blew the line off the filter inside the tank, so it was time to replace that too. When I got it back it was like a totally new bike, better than ever.

[AndyRR]

It looks like a spark plug wire has caused my problem. Work schedule has been hectic to say the least, but before I left this morning I checked for spark on each plug. Nothing on the right. It's SO easy, I'm kicking myself for not checking this before.
So when I returned from work, I pulled the tank and switched the plug wires at the coil. Problem stays on the right, so plug wire it is.

Unfortunately, Bob's BMW is closed today, so I'll have to stop by tomorrow.

like the high tension wire going to ground occassionally.

Good call Boxermania!

I got my mind stuck on fuel issues. I did get the injectors off btw. Another very easy thing to check and see if each injector is working.
From now on, my troubleshooting for a poorly running engine will be something like this:
1. If on the road - fresh fuel and drygas.
2. pull plugs and check for spark
3. pull injectors and check for fuel spray
4. check compression.

If you have the tools handy, 2, 3, and 4 should take no more than 15 mins. 1, 2, and 3 are easily accomplished with the on-board tool kit.

I'll tackle the difference in compression in the off-season.

I'll report back once the new wires have been installed. Thanks all for your help!!

[sweatmark]

Andy, thanks for posting results of troubleshooting. These problem + solution type topics make this board invaluable.

And boxermania, after several years without a Beemer, you're still contributing sage words of motorhead wisdom here for the betterment of group. Thanks!

[CycleRob]

The green gunk in/on the injector plug's terminals means the plug's gasket is NOT sealing out the road spray. That is the first time I have heard of that happening on the OilHeads, but considering the problems it can cause, it really needs to added to everyone's 2 year service check. It'd be a good idea at that time to use a small brush/rag to apply a thin layer of waterproof grease to both the electrical terminal gasket and the injector body's sealing O-ring where it plugs into the TB.

After several years running, my now gone OilHead's idle smoothed out noticeably after the injector removal/cleaning/greasing of the dry sealing O-ring. That injector removal/cleaning/greasing was just part of an unrelated disassembly, but it showed an unreliable, dry, O-ring sealing surface that needed attention. If your idle is wandering when hot, perform that undocumented but rational injector service, or have someone reliable do it for you.

[boxermania]

sweatmark

Thanks for the kind words, mine has been gone three years now, but there are still a couple amongst my friends....and guess where they come with their issues. On the other hand I have always advocated that the more you know about your ride the higher the level of enjoyment, that being said I enjoy helping my fellow riders.

[boxermania]

AndyRR

So when I returned from work, I pulled the tank and switched the plug wires at the coil. Problem stays on the right, so plug wire it is.

If the above is true and the problem remains on the same side, the high tension wire is not the problem, it could be one of the coil windings. Give me a call at (225) 445-6922 to get to the bottom of this.

[iowabeakster]

Glad you got it sorted out!

I was going to make a post yesterday (about spark issues), but it seemed like you already had that on your list of things to check. I started to... and then deleted it.

The "on again--off again" nature of your problem seemed to point to an electrical issue of some kind. The idea about the corroded fuel injector connections...was interesting... never heard of that particular problem before. I guess that would be an electrical problem with the fuel system... which made me think twice about posting about the spark.

The spark is always my first thing to check on a (running... but poorly running) modern fuel-injected engine.


edit---re: boxermania's post

I pulled the tank and switched the plug wires at the coil

You only swapped the coil ends, correct? The other ends remained on their original cylinders.