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Sudden anemic performance

10K views 57 replies 21 participants last post by  Fly-Sig 
#1 · (Edited)
Sudden anemic performance NOT SOLVED update page 2

Any ideas where to start on this one?

'15 V650, about 4500 miles on the odometer. Running 88 octane no-ethanol gas.

Suddenly while out riding around town the idle dropped from 1300 to 1050 rpm. It has remained there when warmed up now. When cold the idle is higher and the engine runs ok but perhaps not as strong as before this happened.

Now when warmed up the engine feels very weak below about 3500 rpm. Between 2500 and 3000 rpm it has almost no power. It feels like a carbureted engine which is running out of gas. It pulls adequately when asking for little, gliding along at 35 mph. But twist the throttle and it feels like combustion just stopped, as if it is running with no gas. Opening up the throttle it will accelerate. At 4000+ rpm it has adequate power for highway cruising and accelerating onto the highway.

Everything seems to indicate a loss of fuel flow, not spark or airflow. Since it runs better at higher rpm and more throttle it doesn't seem to be a blocked fuel line or filter. Agree?

The TPS sensor feels very secure and does not appear to have moved at all.

The problem came on suddenly and seems to be consistent over a couple of rides, around 50 miles total (mostly highway, some city). Not water in the fuel, right?

Fuel injector perhaps? Is there an idle or low throttle injector and a higher power injector? Should I pull the fuel injector(s) or just pour in a can of Sea Foam?
 
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#3 ·
Since I start with the simplest and cheapest-to-fix solutions and work from there, I'd first be certain that the fuel isn't too old or otherwise bad, then I'd check the air filter (particularly if the bike was stored for the winter; critters and crawly things have been known to nest in there) and then add some Sea Foam and see what happens.
 
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#4 ·
I use the highest octane I can get for my '09, even if it has some ethanol (BP calls it Invigorate I think). And, I do a little additive (Chevron Techron) now and then. Does anyone agree to add a little dry gas and add some higher octane juice to see if bad gas may be the problem.

I had a post a few months ago when my clutch would not fully engage unless I pushed the lever back out. I would be on the slab and give it a handful of throttle and watch the rpm's spike, but was getting no power. Turns out the clutch was not blown, just that the cable was getting pinched near the lever attachment.
 
#5 ·
Ok, could this be diesel contamination? I buy non-ethanol gas, and this problem started very soon after the last fill. The pump has 2 hoses, one is the non-ethanol, the other is diesel. There is no way I used the diesel hose, but perhaps they put some diesel in the underground gasoline tank.

I noticed the exhaust smell is quite sulphurous after the last fill. I've never had that before.

Sea Foam has had no effect on improving how it is running.
 
#7 ·
is your bike smoking like a 2 stroke. i remember the tard at the quick stop filling my tank half way up in my 72 VW super and it was even more gutless then normal and smoked blue smoke like a weed wacker. drained the tank and put fresh gas in and it smoked even more for the first like 15-20 min then cleared up and ran like a top after i cleaned the spark plugs
 
#6 ·
Not sure if I am reading this correctly, But perhaps the first thing would be to drain the tank, and fill with a non-suspect fuel source and see if it cleans up.. what you're suggesting about diesel in the underground tank could be possible, but I wouldn't think it likely..I know a sulphurous smell can be linked to a catalytic converter as well..
 
#9 ·
Yup. If there's any question at all about the fuel, drain and refill.
 
#12 · (Edited)
Higher octane than regular (87 octane) won't perform any better because the Versys does not have the high compression to take advantage of it. Ocatan just is a heat rating. Higher octane gas requires more compression/heat to ignite, it exists for high compression engines that generate more heat before combustion, so they won't pre detonate. In some cases it can perform worse in a normal engine and not fully burn off because of this, leaving deposits on your spark plug. The energy contained in a gallon of gas is the same regardless of the octane rating, higher octane fuel is just less flammable - it requires more heat to ignite.

Your engine control module will automatically drop the RPS's by a few thousand when the engine warms up. Basically it raises the idle speed by a few thousand RPM's when the engine is cold, then reverts to normal after it senses the engine is operating normally and drops back to normal idle speed. This comes on suddenly and is nothing to worry about and is normal. There is also an idle adjustment screw on the right side to adjust the idle speed. The warm up RPM drop will usually occur 1-3 minutes after a cold start.
 
#16 ·
No joy. Still doing the same thing. When cold, runs ok. But once thoroughly warmed up it runs like dog sht. When gradually slowing down and the rpms drop below about 4000, the power starts to roll off even with no change in throttle. Add some throttle and it is as if all combustion stops for 1/4 second, then it weakly accelerates. If in that situation a good amount of throttle is added it has good power.

I wasn't able to completely drain the fuel. There should be less than 10% of the bad fuel in the mix now.

Every time I come to a stop in my driveway the exhaust has a sweet sulpher smell. Sometimes strong, sometimes not. I've put in fuel from a different brand altogether, so 90% of the fuel is a different brand.

I'm at a loss other than taking it to the dealer.
 
#18 ·
No engine mods at all. Stock 2015. No engine service yet, other than oil changes. Plus adjusting cables, chain, etc.

No check engine light. No codes in the computer.

I pulled the O2 sensor and it is a bit sooty. I don't know what is normal, but at least it doesn't show signs of coolant contamination. Oil level is steady, so there's no oil contamination.

Since the problem only occurs when the engine is fully warmed up it seems there is either a bad sensor or maybe a bad computer.

I disconnected the battery today in case the computer needed a cold boot. I'll take it for a test ride tomorrow and if it isn't any better it goes back to the dealer. The 2 yr warranty expires in about 10 days.
 
#19 ·
In some ways, it sounds like a bad catalytic converter, but that doesn't seem very likely with low mileage. Is it running hotter than usual? (Another symptom of exhaust restriction.) Considering the history in post #5, fuel contamination is still a strong possibility, even if only 10% remains. In any event, I'd get it to the dealer ASAP to preserve any warranty claims you may have.
 
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#20 ·
The soonest service appointment is 3 weeks away. Dang. I can throw some parts at it but that gets expensive quickly. O2 sensor alone is $100. Fuel injectors, spark plugs, misc sensors.

If fuel got into the evap canister is it ruined permanently, and would it cause persistent problems? I did fill the tank full shortly before the problem started. There is no strong fuel smell or liquid fuel in the canister currently.
 
#21 ·
you should just get rid of that tumor all together, raw fuel in it will ruin it and cause crappy running... i kinda assumed yours didnt have one because everyone takes them off day one
 
#22 ·
Silly question, but when you purchased new fuel, did you use the same station as before? There is a gas station in my town and anything I have put gas in from there ran like complete crap. Needless to say I don't go there anymore.
 
#23 ·
Yeah, I almost always fill up at that station. It has been the only no-ethanol gas around. It is a no-name brand from a refiner nearby. When I'm not going in that direction I'll fill up with other brands.

Since then I filled it by adding 2 gallons from a different brand, then after burning down less than a gallon I siphoned out what I could (all but 1 gallon) and filled up at yet a 3rd station. Still the exact same performance issues, though the sulphur smell seems to have stopped.

I'm presuming water or other contaminants in the gas set off the problem as this began the next day after I filled and rode home (about 3 miles).
 
#24 · (Edited)
If water or contaminants was the issue and you siphoned all but a gallon of the gas out, you still have water or contaminants in the tank. Water and contaminants are heavier than gas, therefore will be at the bottom of the tank with the gallon of gas you didn't get out. Adding fresh gas won't help much, as the water and/or contaminants are still at the bottom of the tank. Being as gas pumps have a fuel filter(which will usually filter contaminants but doesn't do a very good job of trapping water) It's very possible you have water in your fuel. If so, you need to make sure you get every drop of fuel out of your tank, which is hard to do without removing the tank.
 
#29 ·
I disconnected the evap canister with no changes to the problem. I was hoping that was it.

In reading on the fuel injection programming there are 2 modes, D-J and a-N. Now I'm wondering if it is related to the D-J mode which is low power low rpm related. The other mode is for higher throttle settings and higher rpm.

The problem is only when fully warmed up and at those lower throttle/rpm settings.

If parts weren't so expensive I'd just swap out a few things like the O2 sensor and the inlet air sensors.
 
#30 ·
Partial update:

I think it is a bad O2 sensor, likely caused by over fueling or bad fuel. Over fueling can put liquid fuel into the charcoal canister, which somehow causes further problems including very rich mixture at low power low throttle settings, which may have contaminated the O2 sensor. Per the interwebs that is a typical sequence.

Definitely it is running so rich it drowns the engine at low throttle between 3000-4000 rpm after it is fully warmed up, which is apparently a classic charcoal filter failure symptom.

Service appointments are 3 weeks out. New O2 sensors are back ordered 3 weeks from the factory. I did find one online dealer who says he has 2 of them in stock, so with luck I'll have a new one next week. I would rather throw a little money at it than lose most of the summer riding season.

I'll be trying the trick of holding the start button before turning on the ignition to see if I can put it into open loop mode, bypassing the O2 sensor. This may help further refine the diagnosis.

Researching O2 sensor eliminators, I would have bought one as an interim experiment but they seem to only be available from European sellers, and would put me back another week. I may yet try one later on to see if it improves overall engine smoothness since my state does not require the O2 sensor.

The charcoal canister appears to work properly, as air does flow through it. But, there is no 3rd port which would be the outside vent. Perhaps whatever venting it has does not work right. I've noticed for a while the gas tank hisses when I park out in the sun. It has not been properly venting, I think.
 
#32 ·
Yes, main throttle sensor is within spec.

I believe there is an overall rich condition due to black carbon fouling on the O2 sensor and bad fuel economy. Also, the exhaust smells sulphurous at idle once warmed up, suggesting too rich a mixture. But, this is all a guess since I don't have the tools to dig into all the different signals from the different sensors.
 
#33 ·
Now when warmed up the engine feels very weak below about 3500 rpm. Between 2500 and 3000 rpm it has almost no power. It feels like a carbureted engine which is running out of gas. It pulls adequately when asking for little, gliding along at 35 mph. But twist the throttle and it feels like combustion just stopped, as if it is running with no gas.

The TPS sensor feels very secure and does not appear to have moved at all.
Your original assumption was in fact correct. It is lacking power down low once warmed up because of a LEAN condition.

Start by rotating your main (lower) throttle sensor (TPS) counterclockwise by about 0.5mm.
 
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