Rough Idle/Dies - Gen II

[usaffjr]

2006 FJR, ~23k miles, no engine mods, all recalls done (including wiring harness). I've owned it for the last 5 years/20k miles

And yes... I tried the search but my search-foo is weak tonight.

Not sure what's going on, but it started a couple of weeks ago. I started the bike and the idle sounded a little rough. I went to blip the throttle and it died. I started it back up and everything was fine, although every once in a while the idle would dip below 'normal' - I'd guess 800 or so RPMs. Today, leaving work, I didn't realize the bike was idling rough until I got on it (started on the side stand while I geared up -- it was 60-ish degrees out and cooling). Went to pull away and it died. Didn't even get the chance to let the clutch out. Noticed I was down to 2 bars of fuel left, so I went to fill up, expecting like a couple of weeks ago that a restart would fix the problem. No luck. After I filled up the tank, I literally couldn't touch the throttle without it dying. Figured I was stuck for sure. Finally got it to start and gave it enough gas and revved it a few times. Then the idle settled back in, although this time back to the 800 or so RPMs. Started my way home and whenever I initially turned the throttle after shifting gears or to accelerate, it would bog down.

Cruising down the road seemed fine, although I'd swear something was adding extra resistance. Can't explain it more than that. At one point as I pulled away from a light, I noticed anything around 4k RPMs made the engine vibrate more than I've ever felt. It was a deep vibration, if that makes sense. All these years and other than recall-related issues, I've never had a serious problem. Really would rather not have to park it for a while...

What could be the culprit? I know I'm getting close to the 24k mile service needing the valves adjusted, but I was hoping to last until after the new year. Could that be it? I had this happen on a car once and it was the catalytic converter that had broken down/gotten clogged. Although that was a more steady decline in performance.

Appreciate any help you could give!

[silverback]

I'm not horribly experienced with the FJR, and I have never heard of an FJR needing one, but those symptoms are classic fuel pump failure on cars.

Cold needs extra fuel for enrichment, a lot of extra fuel. (Like a choke on a carb) So they don't run well cold. Rough idle, during, etc.

As it warms up, the idle fuel demand goes down and it starts running better...until you need power.

At operating temp, it feels like a slug and any acceleration is not at all available.

Usually fuel pumps die from being run empty. The fuel flowing through the pump cools and lubricates it. No fuel, it gets hot and starts melting the impellers.

So, it would be worth while to do a fuel pressure check. That will tell you for sure.

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[clocklaw]

Start with the simple stuff. Is there water or trash in the tank? Being as it is intermittent, trash could be the culprit. When you add fuel it will stir up the trash settled at the bottom of the tank and give it a chance to get to the pickup.

[usaffjr]

Wonder how trash could end up in the tank... especially considering I've had it for so long...

I'll have to drain it to look. Shouldn't have filled it up!

[silverback]

Shouldn't have filled it up!

That's usually the second sign its a fuel pump. The chances increase with the volume of the tank and the difficulty of taking the tank out.

On an FJR, you could add an additional 10%. On a 90's Beretta, 0% because its one of the only cars with a hole under the seat to access the pump. On a 90's Chevy that's spent its life in a feed lot, add 147%, and if they were nice enough to clean it, add 173% due to the cowshit being nice and gooey instead of dried up and caked on.

You don't ride the FJR in feed lots do you?

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[usaffjr]

No feed lots for this guy... and I haven't been to any sketchy old gas stations either. I don't even have something that can hold that much fuel.

Any chance I can do damage by continuing to ride so I can use up the fuel?

[bluesdog]

Possibly partially clogged fuel injector(s)

Check by lifting/propping, (not full), gas tank up, disconnecting the electrical connector from individual injectors -- it's likely only one, or possibly two injectors.

They must be removed for proper service, and a few new parts are required, such as screens and o-rings.

[usaffjr]

When I unplug an injector it's going to run poorly, right? How do I know something is wrong with it by unplugging it?

[silverback]

When I unplug an injector it's going to run poorly, right? How do I know something is wrong with it by unplugging it?

If its the bad injector, it won't change.

If you're going to all this trouble, check the fuel pressure while you're there. Not worth taking the thing apart more than once if you can help it.

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[ionbeam]

When I unplug an injector it's going to run poorly, right? How do I know something is wrong with it by unplugging it?

It works the same for the spark plugs too.

Each injector should be doing an equal amount of the work. Unplugging one at a time, the engine performance should always change the same amount. If one injector is clogged and not doing its job, when unplugged there will be less of an engine performance change.

Another way to get this information is to check the header down tube temperature if you can. The cool tube or the really hot tube = the bad cylinder. The header tube temperature difference will be significantly more than a few degrees and will be obvious.

Edit: I see Silverback answered the question while I was fiddling with this reply.

[usaffjr]

What's a good way to check fuel pressure? By the way, assuming it isn't dying, since this is intermittent, can I continue to ride, at least until I run the gas out, without doing damage?

[Bounce]

Before jumping to a pump or injector, KISS.

Filling from a station that just got gas from a tanker an stir up the crap that's in their storage tanks. Go elsewhere if you see a tanker dropping a load at your favorite station. That junk gets in the tank and is pulled toward the intake from the fuel pump suction. It drop away from the intake when the bike is turned off and repeats the process with each run. If it's trashy gas it's a pain but draining the tank and refilling with good fuel will usually fix it. If it's moisture in the tank, then some gas dry additive can help until you run it nearly ry and then refill with good fuel.

Check the idle once it's at operating temp. Should be 1100 RPM. Anything below can cause what seems to be a rough idle and intermittent stalls. Adjust it while sitting on the bike, keeping it upright, and use the adjustment knob under the right lip of the tank near your knee.

How old are the plugs? Replacing them can help.

Only after you do the easy stuff should you worry about the more costly stuff.

[tominca]

Speaking of easy stuff, how long since you changed the air filter or plugs? I'm overdue and having no operability problems, so just spit-balling really.

[usaffjr]

Been a while for the plugs and the idle definitely has been lower lately. I'll try that and add some sta-bil.

[usaffjr]

Got to thinking - wonder if this has something to do with the charcoal canister removal I did a couple of years back. Long road trip and some really rough road a couple of weeks ago... also noticed my coolant hose is leaking, right above the overflow bottle.

[silverback]

Got to thinking - wonder if this has something to do with the charcoal canister removal I did a couple of years back. Long road trip and some really rough road a couple of weeks ago... also noticed my coolant hose is leaking, right above the overflow bottle.

Probably not. All the charcoal canister does (typically) is hold gas fumes until the engine is at cruise state, then releases them into the intake to be burnt. The biggest benefit of charcoal canisters is that vehicles don't stink up the garage anymore.

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[usaffjr]

I was thinking maybe the tee or plugs I put in might have come loose. I'm going to take a peek today.

[silverback]

I was thinking maybe the tee or plugs I put in might have come loose. I'm going to take a peek today.

Typically vacuum leaks cause high idle and no noticeable difference at speed. Unless its a leak that is humongous. Or if its not a leak to air...vacuum leaks to coolant do terrible things.

Have you pulled codes? I know they are pretty simple on FJRs but they can start narrowing down a problem. FWIW, the more elaborate codes (I.E. OBDII codes) the higher the chance they are wrong. So, simple codes are good. LOL.

If you do pull the plugs, you might post a picture, they are also a great indicator of engine problems.

I'd still check fuel pressure as well.

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[raYzerman]

Back to basics...... you're really not riding that much, so battery needs to be fully charged first. Next, if the fuel is 2 weeks old or more, the ethanol has likely separated along with some water. Add Seafoam to the tank as it has isopropanol in it to dissolve the water. Hopefully that gets you going ok. Run out that tank of fuel, and for the next couple of tanks, use Seafoam or Yamaha Ring-Free to dissolve any gums that might be lurking in the fuel system. Ride regularly for more than an hour at a time. Commuting isn't the best for a bike. In your case, I would put Seafoam in every other tankful.


Next, go over all the ground spiders, clean them with a brass brush (so you don't take the plating off the spiders) and lube them with a contact paste (OK since they are all ground wires). Otherwise use dielectric grease, the point being to keep moisture out and reduce chances of corrosion.

[usaffjr]

Thanks, I'll try that after I get the service done. Need to replace my thermostat before doing any more riding... and might as well get my valve clearance checked while the coolant is drained...