HELP! - Terrible Fuel Efficiency on SV650s w Power Commander | GTAMotorcycle.com

HELP! - Terrible Fuel Efficiency on SV650s w Power Commander

Marcfolch

Marcfolch

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I bought a 2005 SV650s at the start of the season and it was running fine with about 250km on a tank until the indicator came on (~15L used). Now I'm only getting 160-170km before it's been coming on. This bike should be getting around 250-300km on a tank.

It came with a Power Commander III which I was told was dyno-mapped but I don't trust the dealer at all. Am going to load the default map for this bike with the M4 exhaust (which it is equipped with). I will be installing a new K&N filter as soon as my order comes in as the old filter is really dirty. However with the O2 sensor, I have trouble seeing how this would lead to a 50% reduction in fuel efficiency.

Since getting the bike I put in a new chain tires and sprocket. If anything, these should be reducing friction and mileage, not the other way around. Tires are properly inflated, Bike does not smell of fuel, does not smoke a lot, or backfire or anything.

I really need to get this fixed because I leave on a 7,000km ride in a week and a half. I can't be fueling the thing every hour. PLEASE IF ANYONE HAS ANY IDEAS WHAT THIS COULD BE, LET ME KNOW!

Thanks in advance
 
My experience with default PowerCommander maps has been that they are obnoxiously and unnecessarily rich in the part-load cruising region. (On a bike that was obnoxiously and unnecessarily rich to begin with, they did not address this.)

You are better off editing the maps yourself rather than trying to find a nonexistent map to address this.

Now ... important question. When you originally got the bike and it was doing 250 km per tank, and now it's only doing 160 ... What changed? Did that change coincide with installation or mapping of the Power Commander? If it did not change with the installation of the PowerCommander, what DID change that resulted in this difference?

I am going to ASSume that the 250 km per tank was without the PowerCommander installed, and then you installed the PowerCommander. If that is the case then you have a screwed up map installed. If the situation is something else then explain the missing piece of the puzzle. What changed?

If the problem is that you have a screwed up map ...

First fill the bike with the most oxygenated fuel out there ... Sunoco/PetroCanada Ultra 94. (I never use this fuel for anything other than calibrating for how lean we can go ...)

Connect your laptop and cable to the bike and start the PowerCommander software with the engine running / key switched on (whatever you need in order to access the map). Save the map to your laptop as it is right now so that you have a known state to go back to if something goes haywire.

Now, go down the 0% column at all engine revs starting with 1500 rpm all the way to redline and subtract 5 (in absolute terms) from each number in that column. By "in absolute terms" ... 8 minus 5 is 3. 2 minus 5 is -3. -7 minus 5 is -12.

Do the same thing for the 2% column, 5% column, and 10% column.

Now go ride the bike and see if there are any driveability issues when cruising at various constant speeds or in gentle acceleration. The engine load at such small throttle settings is so light that you need not worry about doing damage. Feel for hints of surging or hesitation, which are the symptoms of being too lean. Chances are, it will feel exactly the same, maybe even better (if my suspicion of being too rich is correct).

If all is well then repeat the same step again. You can keep right on going leaner and leaner until you start feeling signs of flat throttle response, stumbling and hesitation on gentle acceleration, surging at constant throttle cruise, etc. If you get such symptoms, note the RPM at which it occurs and take a guess at the throttle position. Since you know the setting 5 higher than this was OK, try adding 3 (in absolute terms ... once again, negative-12 plus 3 is negative-9) in the RPM range in question. Go a little above and below just to make sure. Repeat, repeat, repeat ...

Once you have all this in the ballpark, feel free to use the 20% throttle position column to blend whatever you found for the 10% throttle with whatever is in the 40% column so that there is a smooth transition between your new "lean cruise" part-load map with the "power" settings at 40% throttle and above (which you should not touch).

Expect this to take a fair bit of trial and error. Expect to discover circumstances months later that you hadn't originally anticipated and thus needing to make further adjustments. You are NOT going to find any such map pre-made for you. And NO dyno shop is going to take the time that it's going to take to do this, and you wouldn't be able to pay their price even if they would.

My ZX10R map developed in this manner has some parts of the map at -35 (taking away 35% of the original fuel delivery) ... after about a month of tweaking followed by discovering at the drag strip that a long coast-down period resulted in the engine internals cooling off to the point of causing a lean-misfire (a circumstance that I didn't originally try out). Power is unchanged (because the full-load part of the map is not touched), driveability is impeccable (because I'm fussy), it doesn't run hot or detonate or do any of the other things everyone warns about when using lean cruise (they're doing it wrong), the engine oil no longer smells like fuel when it comes time for an oil change (translation: excessive fuel is no longer washing the oil off the cylinder walls and getting into the crankcase), the spark plugs no longer turn black, and fuel consumption has improved from 7 -8 L/100 km to around 5.5 L/100 km and that's despite putting drastically shortened dragstrip gearing on it at the same time ...
 
Wow, thanks so much for the detailed response Brian P. You're awesome guy!

The PC is the exact same as when I first bought the bike. Did not re-map, or touch it in any way. I suppose it is possible that the buttons got pushed by me overfilling my (sorry excuse for a) trunk, but other than that, no changes at all to the air or fuel system.

I did a spirited ride in the country on Sunday and noticed something i'd never noticed before. The bike didn't really start to pull at WOT until it hit 9k RPM. I might be mistaken, but i don't remember this reaction before on the SV which is supposed to have nice strong pull nearly anywhere from around 3k RPM up. Could this be an indicator of richness?

So if I understand your recco, I need to manually remap everywhere from idle up to 20%. Do you recommend any changes above that?

To know if I've leaned it out too much, I keep going until it intermittently surges at steady throttle, then adjust up a few %. Anything else I need to watch for? I want to make sure I'm not over-leaned because i'm doing this trip down to Florida with 35c weather.
 
If you have not touched the PowerCommander or the map then the problem is not likely to be the PowerCommander map. Don't use re-mapping to cover up a real problem that is something else.

What's the condition of the air filter? (edit: Saw in your original post that you know it's dirty. Change this before you touch anything else!!!)

The boggy feel below 9000 rpm and combined with poor fuel consumption are consistent with a too-rich condition, the next question is WHY.

It's possible that you are starting to get deposit build-up in one or both injectors, causing them to dribble and/or not spray properly. Run some injector cleaner through it.

It's possible that the valve clearances are too tight, causing high cylinder leak-down, which will make it run rich (among other symptoms - i.e. low compression).
 
Air filter is completely clogged. Found acorns and rodent pellets in there when I opened the airbox for the first time. I originally ordered a regular filter and they told me the next week that they didn't have any and it was discontinued. So i placed an order for the K&N. Should be here in a day or two. I thought the sensors automatically adjust for input air, so this would cause a loss of power but not fuel efficiency loss.

Will run some injector cleaner through it tonight.

The bike's coming up on its 30k service and I do not know if it has ever had its valve clearance checked. I really hope that not the issue because that's an expensive one. Would it account for a drop from 250km/tank to 170km/tank in the space of a couple weeks?
 
Fix the known issues (air filter) and do something about the cheap issues (injector cleaner, and put in new spark plugs) before you start dealing with expensive, uncertain issues (valve clearance). But DO get the valve clearances checked, particularly given that it's overdue, and you have a long trip coming up.

As far as I know, your engine doesn't have an O2 sensor, and it certainly doesn't have a MAF sensor. If something causes abnormally low airflow through the engine, the computer would have no knowledge of it and therefore cannot correct for it. With the exception of a few select models (of which yours is not one of them), bikes have not really gone towards closed-loop EFI until the last couple of years.
 
Marcfolch said:
The bike's coming up on its 30k service and I do not know if it has ever had its valve clearance checked. I really hope that not the issue because that's an expensive one. Would it account for a drop from 250km/tank to 170km/tank in the space of a couple weeks?
Click to expand...

You need to get your valves checked and adjusted if need BEFORE it starts to make the bike run improperly. I find myself talking to riders about checking valves all the time because its so important to check, and no one has any concept as to why. This is the main reason most sportbikes explode at 30K and people have no idea why. Long story short if you dont check it for long enough the valve will hang slightly open when it's supposed to be closed, which first will make the bike run like crap, and then eventually as it hangs open farther will cause the piston to slam into the valve most likely writing off the engine. Checking your valves at the required service intervals is not something you should be pushing off to later!!!!!

It could cause your symptoms, but acorns and crap in your air box is the far more likely culprit. The engine is only going to adjust for fuel by a small margin, and the more important thing to think of is if the engine isn't getting air and running bad, you need to use more throttle to make it go, which uses fuel. Most people dont realize that large throttle openings uses more fuel then high rpm with the throttle just barely cracked.
 
Do both wheels spin freely on a stand? A dragging brake does nothing good for fuel economy either
 
Marcfolch said:
Wow, thanks so much for the detailed response Brian P. You're awesome guy!

The PC is the exact same as when I first bought the bike. Did not re-map, or touch it in any way. I suppose it is possible that the buttons got pushed by me overfilling my (sorry excuse for a) trunk, but other than that, no changes at all to the air or fuel system.

I did a spirited ride in the country on Sunday and noticed something i'd never noticed before. The bike didn't really start to pull at WOT until it hit 9k RPM. I might be mistaken, but i don't remember this reaction before on the SV which is supposed to have nice strong pull nearly anywhere from around 3k RPM up. Could this be an indicator of richness?

So if I understand your recco, I need to manually remap everywhere from idle up to 20%. Do you recommend any changes above that?

To know if I've leaned it out too much, I keep going until it intermittently surges at steady throttle, then adjust up a few %. Anything else I need to watch for? I want to make sure I'm not over-leaned because i'm doing this trip down to Florida with 35c weather.
Click to expand...

SOMETHING changed between 250km/tank and 160km/tank. If you didn't change anything yourself, then you have some kind of failure on your hands. Until you find the problem, don't take this bike on your planned trip.
 
After performing the recommended actions above (replace air filter, check for dragging brake, injector cleaner, and spark plugs), and after you have checked to make sure any of these changes altered the milage problem, then maybe you should consider disconnecting the PCIII temporarily to isolate the problem to the PCIII or to the bike. As I understand it, the PCIII is placed between the ECU and injectors so its removal will be relatively straight forward.

If the diagnosis shows the bike to still have fuel efficiency problems, take the recommendation not to bring the bike on a long trip until the problem is isolated, identified and fixed.
 
robmack said:
After performing the recommended actions above (replace air filter, check for dragging brake, injector cleaner, and spark plugs), and after you have checked to make sure any of these changes altered the milage problem, then maybe you should consider disconnecting the PCIII temporarily to isolate the problem to the PCIII or to the bike. As I understand it, the PCIII is placed between the ECU and injectors so its removal will be relatively straight forward.

If the diagnosis shows the bike to still have fuel efficiency problems, take the recommendation not to bring the bike on a long trip until the problem is isolated, identified and fixed.
Click to expand...

If he doesn't have the stock exhaust he may run into o2 errors. There has to be a way trick it out.
 
Brian has some great info here. While I have no need for a PC now and probably not in the future unless I were to invest in a track bike at some point, I'm still making a draft of a couple of his posts here. I really liked how he covered so many bases and personal opinion on possible grey areas also. Will refer to these notes if I hear of a friend wanting to set theirs up properly.

Now I can't add much to this thread except for something you mentioned that does account for an overnight fuel mileage drop on any bike that reads its speed off the front sprocket. And it certainly won't account for all of your drop, but it does account for more than many realize, especially on some bikes and brand/model of tires. And it is simply the difference in diameter of a new tire vs one that is worn out. And this difference can be compounded if you happened to have bought a new tire that differs from the profile/diameter of the OEM rubber, which is what the odometer is calibrated to. In many bikes, this can equate to as much as 2 - 5 mpg. If you happen to be skeptical on this, this can be proven by using a GPS both before and after swapping out the old for the new tire.

As someone who once bought new rubber every 2 - 3000 km (sportbike compounds on RR's) I have replaced a PILE of tires in my years and always have tracked mileage for various reasons...some of which lets me know if a thermostat or sensor had gone or going bad. Took me a while to put 2 and 2 together but finally made the assimilation. Felt a bit thick when it did finally dawn on me, because of course, a new tire turns fewer revolutions in the same mile than a worn out one does.
 
While you could absolutely tune an engine the way brian describes, from my very limited experience with automotive EFI tuning i actually disagree with most of that. I wouldn't tune an engine with anything other then what you planned on running with it fuel wise (in the case of an SV, 87), and i would tune with an 02 sensor, logging data and editing. When tuning an engine with spark tuning capability you can tune something designed for 91 to run even better on 94, but an engine designed for 87 is not only way too low compression, in this case you dont have spark advance tuning.

Try all the simple fixes and if it doesn't work, disconnect the PC. Not sure if it's possible for them to fail or what would happen as a result, but my race SV runs on 87, has a full m4 system and a BMC race filter, runs like a top and the plugs look great when i remove them. Not a scientific way of telling how an engine is running but with the flawless power delivery as well i'm not the least bit concerned.

Neso how in the world are you going through tires that fast on the street?! I hope that includes a bunch of track days.
 
Thanks to everyone for the advice. I really appreciate the help. BTW, anyone have objections to using Sea Foam in a sportbike?

Brian P:
The K&N came in earlier than expected and is now in the bike. Will put in seafoam with the next tank and go for a good long ride tomorrow. The good thing about this problem is that it only takes 170km of riding to find out if it's fixed lol.

FriendlyFoe:
Is there any way to cheaply check the valve clearances? I understand it is one of the most expensive services there are. I've already had to put in new tires, a new chain, a new rear sprocket and a new air filter since I got this bike at the start of the season.

JC100:
Sprocket that came with it was a worn out aluminum with a few less teeth than OEM. Now it's a steel OEM.

ASH:
Pretty freely, they don't spin and spin and spin like bicycle tires, but they'll go a bit before stopping. I suppose it's possible to have a dragging brake. Wouldn't that make the disks hot after most rides? I did a half hour ride on the highway today and felt the discs, no heat at all. If that wouldn't be an indicator, how would I check for and/or fix this?

Fastar1 and Robsmack:
Yeah I have a week and a half, so hopefully we can figure this thing out. Got everything all set up including a borrowed $1.5M condo to stay in when in Miami, so it would be a shame to cancel.

IiIsWhatItIs:
From what I can tell, it's an M4 full exhaust system.

Nesobriquet:
Could definitely be a combination of the new tires (Pilot Road 3) vs old (Stock Dunlops) and the new higher tooth sprocket throwing it off. It makes sense that this would have some effect, especially the sprocket but it's got to be something else too in order to get it from 250 down to 170. That quite a mileage drop.

Will see what the K&N + Sea Foam do for my mileage on the next tank and I will report back.
 
Marcfolch said:
Thanks to everyone for the advice. I really appreciate the help. BTW, anyone have objections to using Sea Foam in a sportbike?

FriendlyFoe:
Is there any way to cheaply check the valve clearances? I understand it is one of the most expensive services there are. I've already had to put in new tires, a new chain, a new rear sprocket and a new air filter since I got this bike at the start of the season.
.
Click to expand...

Sea foam is like liquid gold for running through clogged carb passages, i'm not such a big fan of putting it through fuel injectors. I'd put a full tank of riding on the bike tomorrow without it and see if your problems fixed. Just how much animal crap was in the air box?! If there was a whole bunch and you're still wondering why it was running bad that would leave me scratching my head.

If you can remove the tank you're half way through (okay 1/4 lol) doing a valve inspection. Pull the spark plug, 3 bolts on the top of the valve cover, pull the hose off and the valve cover comes off. Dont remove the emissions thing on the top of the valve cover like in the pic, just disconnect the hose, the write up on SV rider lacks a lot of info. For the front cover unbolt the rad at the mounts but dont undo the hose, it will drop forward enough to get at the cover.

CIMG1085.jpg



There are two plugs on the left side of the engine, for now i think you only need the middle one out (actually havent done this on my SV yet, and have no excuse why normally you have to take the case cover off, not just a plug, SO easy)

CIMG1083.jpg


I've only done this on my kawi so im 99.9% sure i want to say to turn the motor over by the bolt in that center plug (you'll need both spark plugs out to do this) and you'll notice theres pointy things under the bolted down covers in this picture. This should happen without too much effort.

CIMG1086.jpg


As you turn the motor over it will want to rotate into 4 different positions (4 stroke, not sure if thats obvious or not lol) when the cam (pointy things) is pointing upward you use a feeler gauge to measure the gap between the lobe (individual pointy thing) and the bucket underneath it. There will be a specific gap to measure when the lobe is pointing upward (either of the 2 positions it will sit in), this is the valve in the closed position and there should be a gap! If there is no gap this means the back side of the lobe is opening the valve which is bad, and will lead to the valve being open while the piston is traveling upward, BAD.

**important point**
When pulling the valve covers off its a really good idea (and mandatory if you wreck them) to put new gaskets on. Dont take the valve covers off until you have new gaskets for them.
 
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Marcfolch said:
I suppose it's possible to have a dragging brake. Wouldn't that make the disks hot after most rides? I did a half hour ride on the highway today and felt the discs, no heat at all. If that wouldn't be an indicator, how would I check for and/or fix this?
Click to expand...

Yeah, dragging brakes are pretty obvious - they'll get extremely hot and smell bad. I just mentioned the brakes because it's possible to incorrectly reassemble the rear brake components when the sprocket and chain is replaced, and that's one of the only things you mentioned that changed between the good mileage condition and the bad mileage condition. It sounds like the clogged airbox is by far the most likely candidate, though.
 
So put in the K&N, added some injector cleaner and have so far driven 220km with no light even though it was under-filled by about 1cm, spent an hour idling in rush hour traffic, had some spirited country riding, and had a pillion for about 20km. Seems like it was the air filter.

I have to admit that this surprised me because I had done a fair bit of reading on other forums including SV650 ones and quite a number of people seemed sure that the SV was a closed loop system that self regulates for the air going in. Based on that I figured that a dirty filter could not account for a 40% drop in fuel efficiency, but it really does!

Thanks again to everyone who provided help!
 
So you wonder why air not being able to flow into the motor would negatively effecting fuel mileage? Didn't you say they were nesting in there? Lmao
 
Marcfolch said:
So put in the K&N, added some injector cleaner and have so far driven 220km with no light even though it was under-filled by about 1cm, spent an hour idling in rush hour traffic, had some spirited country riding, and had a pillion for about 20km. Seems like it was the air filter.

I have to admit that this surprised me because I had done a fair bit of reading on other forums including SV650 ones and quite a number of people seemed sure that the SV was a closed loop system that self regulates for the air going in. Based on that I figured that a dirty filter could not account for a 40% drop in fuel efficiency, but it really does!

Thanks again to everyone who provided help!
Click to expand...


make sure your o2 sensor is working.
see here:

http://www.svrider.com/forum/showthread.php?t=113173
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