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Solved Fuel efficiency drop

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by dbrain, Sep 13, 2016.

  1. Hey guys,

    Back again for my quarterly+ "my bikes being weird". Street Triple 660.
    My fuel efficiency randomly decided to drop about a week ago. Previously I'd get 2 commutes (130km per commute) before a fill, generally the second commute the bike would start in the mid-200's "range" wise, which felt a bit optimistic, but I'd fill it with around 70-100 "range" remaining at the end of the 2nd commute.

    It's now reporting that I'll be super super close to running out of petrol 1 commute in. 140km range. Last time it did something similar, although a bit less "risky" (160km or something). Reporting way less than it previously would after the same distance.

    I figured it was an ECU thing that would sort itself out, but it seems to be getting worse rather than better. Still possible it's just that, but I'm really paranoid I'm going to run out of petrol proving that right/wrong.

    Is there anything obvious that could effect fuel efficiency quickly?
    I've checked:
    1. Clutch lever. It was maybe a little tight (still had slack but under recommended), loosened that up a bit.
    2. Fuel quality.. kinda.. in that I use the same petrol every time from the same station (BP Ultimate)
    3. General once over bike checking chain etc.
    4. Tyre pressure (check it every night out of paranoia, always run the same 40/34)
    I've heard air filter could cause fuel efficiency problems, but I feel like that would be a slow death, and it had a major service 3300km ago.

    Any other ideas?

  2. Stop riding it at full throttle
    • Funny Funny x 4
  3. Is it actual economy that has changed, or just the "kms to go" on the dial? Are you putting in a full tank when it is telling you it is empty, or just half a tank? I would be expecting it to be something about the sensor and onboard computer if nothing else about your riding has changed.

    Also, head winds can alter fuel economy pretty quickly. I have been stranded 1 km from a petrol station once when I would have usually got there due to strong headwinds.
    • Agree Agree x 2
    • Informative Informative x 1
  4. It's possible the range calculator has become inaccurate. You need to carefully measure how much fuel you are putting in at each refill to determine the true usage pattern. Try filling after each commute just to get an idea what you're really using.

    I have no idea whether this hack still applies to recent model, but in the early days of EFI you could get the ECU to self-diagnose and reset by starting the bike from stone cold and just letting it warm fully up without touching throttle or other controls.
    • Like Like x 1
  5. It is possible if there is a sensor issue it is running in Open Loop mode which will be more fuel consumptive.
    Is the Engine light On?
    Does the engine light come on during startup to prove the globe is intact?
  6. Riding it as I always have (full throttle), and didn't randomly add a bunch of weight to the bike, via cake or anything else.

    It's hard to tell, so far all I have is "kms to go" on the dial to go by, and the gauge itself. But I think they're linked. Last time I took it to a shop they reset it, and my full tank was saying it was dead empty for a km or so.
    I always fill fill the tank, because I hate stopping for petrol. So it's always the exact same commute with the same petrol station stop filling it to the brim.

    The winds are always pretty horrible once you get past a certain point of the freeway, hasn't really changed in that regard, and hasn't been super windy for the last few commutes.

    It's probably just the ECU being a weirdo, I just thought it would correct itself pretty quickly if it wasn't a real issue.
  7. No engine light, and it's still coming on when I turn the bike on.
    I have an OBDII cable, might plug it in (never used before) and see if TuneECU tells me anything.
  8. Tyre pressures.
    Air cleaner might be getting due for a change.
    Injectors might be dirty (unlikely)
    You're wearing a bulkier jacket/pants
    • Funny Funny x 1
  9. Worthwhile, It will give you any current error codes if they exist.
  10. I agree with titustitus, work out how much the bike is actually using on the commute and not what the range indication is telling you.
    ie. before your commute, fill up to the brim, record the odometer reading. Next time fill up to the brim again and check the odometer. you will get an accurate consumption figure from this and then you can calculate your actual range you can get from a tank. now see if the range indication is accurate.....
    • Like Like x 1
  11. But are you putting in the same amount at the bowser as you used too?
  12. Having a battle with TuneECU, so far not winning.
    Unsure if the amount I'm adding is the same, as I just blindly fill it then pay. The price didn't seem abnormal, but with the way fuel prices bounce around these days the range is anywhere from about $14 to $18.

    It's probably just the ECU playing funny buggers looking at the amount I've paid this financial year on average for fuel. It was on the lower end. So unless petrol prices were much cheaper last Thursday something is lying to me. Guess I'll find out if I end up stranded on the way home.
  13. Yeah maybe your ECU is giving dud range readings
    or maybe you need a new dashboard. if so please ask chillibuttonchillibutton for assistance :ROFLMAO::ROFLMAO::ROFLMAO:
    • Funny Funny x 3
  14. Your bike has had it. It's stuffed. I'll take it off your hands for $100
    • Funny Funny x 4
    • Like Like x 1
  15. Somebody call???

    • Funny Funny x 7
    • Winner Winner x 3
  16. I've got the same tool kit except I have a bigger Hammer
  17. Some (not sure about Triumph) ECUs actually use historical data to 'calculate' range and fuel consumption.

    'Calculate' is a generous terms - it's pretty much a baked in linear plot.

    By the very fact that you are filling more frequently, will less kms travelled, you are adding positive bias to the ECU 'calculation'

    Now - this might not be the case with your model - it is however pretty common with Denso ECUs (I know Aprilia uses them)
  18. Preparing for brain surgery........ :)

    Ooooooohhhhh......right in the Dashboard.......
    • Funny Funny x 2
  19. have you done an O2 sensor delete? or otherwise tuned ECU to ignore it?

    or accidentally poisoned O2 sensor using octane booster?
    • Informative Informative x 2
  20. Does a puddle form under your bike when stopped?
    • Funny Funny x 2