half tank + cold air = hard start ---- why?

Discussion in 'Indian Scout' started by webmost, Mar 6, 2017.

  1. webmost

    webmost Bronze Member Supporting Vendor

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    This is a mind bender.

    Give me less than half a tank of gas on a cold morning and Sopowa gets flat out reluctant to start. You would think that with fuel injection your fuel level would be irrelevant. Sopowa should pump up her pressure and that would be it. Why not? Any other fuel injected bike I've owned it doesn't matter. If you've ever had occasion to test your fuel pump by connecting a tube from the fuel rail to the tank fill hole then you know these pumps will piss like a horse. It should definitely be pressure and not gravity that controls the flow. I know from this forum I'm not the only one. In fact, several say pump it twice. Why twice? The second whine should be redundant.

    Is there something in the pressure regulator that doesn't like cold?
    Is there something about the fuel pump that doesn't like cold?

    Baffling.
     
  2. Sitting Bull

    Sitting Bull Junior Member

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    I remember a thread about this a while ago, and I think there was an explanation, but I don't know where it is.

    Well, that wasn't very helpful. Sorry about that.

    I experience the same thing, by the way. 'Tis peculiar indeed.
     
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  3. rodhotter

    rodhotter Member

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    if your engine is turning over too slow look no farther than the 20-xx oil your prolly using!!! unless of course your battery or charging system is lacking. 20W mineral oils flow poorly in colder weather + while your cranking with minimal lubrication you are wearing your engine. engine oils need be calibrated for various weather, try a 15W-xx or better yet 10W-xx oil, the lower viscosity # is cold flow!!
     
  4. raysred1

    raysred1 Senior Member

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    Mine has always started good until the last two starts in this past cold weather. I don't think mine is an oil issue. Could be the sitting in the cold for a time period between starts.
     
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  5. Rudy Smith

    Rudy Smith flying down the road trying to loosen my load. Gold Supporting Member

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    As the tank cools it creates a wee bit of a vacuum that your injectors are pulling against - my speculation.
     
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  6. rodhotter

    rodhotter Member

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    mineral 20w-xx oils are a measured 20W-xx at 40C or 104F as it gets colder it gets thicker aka less vicious + mineral oils group I II + III thicken at a faster rate than than real synthetics Group IV + V oils of the same viscosity, a simple oil change can tell the truth!! my now gone 06 1200 HD sportster would kill my battery trying to start setting in a 40 something degree F garage with 20-xx oil, changing to 10w- xx it started like summer!!
     
  7. ScotD

    ScotD Silver Member

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    1/2 tank + cold morn:
    Have you tried first opening the gas cap, then closing it, then try starting?
     
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  8. webmost

    webmost Bronze Member Supporting Vendor

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    Yep... and clipped my whistling gas cap valve, too.
    Tried thinner oil.
    Replaced battery.
    Tinned cables.

    The question is not what can you do to fiddle with it. The question is why the hell.
     
  9. rodhotter

    rodhotter Member

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    if your cranking fast enough one would think spark issues, pull a plug + ground it + check the spark while cranking. it gotta be electrical or fuel. how many miles, do you use good gas, lots of things to check, good luck!
     
  10. AZmitch

    AZmitch Bronze Member

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    How many miles on your bike?
     
  11. webmost

    webmost Bronze Member Supporting Vendor

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    26k

    ... wait a minute ... might be thinking of the wrong bike. Lessee, the beemer has 95, the KLR has 50, the Guzzi may be the one with 26, the Indian, I dunno, maybe 20

    hard to keep up
     
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  12. webmost

    webmost Bronze Member Supporting Vendor

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    Been the same way all along. This is not a new problem, nor is it specific to me.
     
  13. AZmitch

    AZmitch Bronze Member

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    No problem, I was wondering if you might be in that range where the starter can cause issues with starting? I typically think of a starter problem being one where it draws too much current. In the case of the Scout, it can be that, but it can all be one where it draws too little current. Not only does this affect it's ability to fire the engine, but that lower draw can result in excessively high resistance on the fuel rail (injectors). That can cause issues with starting. I would imagine it would be exacerbated in cold weather. Once they replaced my starter, all the starting issues in cool or even average temperatures stopped.

    It sounds like yours is something else, but if it's in for service, you might consider having the starter draw checked and the resistance on the fuel rail checked? Just a thought...
     
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  14. webmost

    webmost Bronze Member Supporting Vendor

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    Yeah, I did that last Winter. And I specifically told them to test the starter motor. There's a procedure in the service manual. I would do it myself except I didn't want to yank off the radiator to get at it. I even ordered up a new starter cable, tinned the ends, and handed it to them to install while they were down there. They swapped in a new battery & handed me back my cable & told me fixed. I asked did they test the starter, & they said yes, it started. So much for that.

    But look here, everyone is missing the point: I am asking what the hell is going on. I'm not asking how do I fix this.

    Biggest diff in cold starting came when I rode Sopowa up to have her puter flashed. Big diff. Now, she cranks way longer than she did before. Before: crankittycrank bloowee. Now: crankittycrankittycrankittycrankitty dunno when it would stop. No bloowee. Second thing that happened is, now, cold start idle spins about 1600 rpm, immediately subsides to 1450 rpm, drops to 1250 around engine temp 100, then drops to the ordinary 1150 on down the road.

    Now, granted, still not a good winter bike. If engine temp is below 30, lotsa cranks, then she will limp along on one jug for a half minute, as tho the other jug got flooded. (Have not smelt gas from the exhaust, tho). Would not rely on this bike to commute when temps are say 15 degrees, cause I have serious doubts she would start after parking outside the office all day. I've been riding Goldenbitch, the Guzzi Jackal for that. Similar size engine, also fuel injected, similar sized battery, beefier looking starter, starts right up. Press button boom.

    I can feature myself fueling before Asheville & riding Goldenbitch up Mt Pisgah during leaf peeping season, waking up to a hard frost, & having zero problems getting off the mountain. I imagine Sopowa under identical conditions, half a tank or less, hard frost, I'm stranded until afternoon. Which is pure bullschidt far as I am concerned. But fill last thing in Asheville, I should be good to go. Which is pure baffling far as I am concerned.

    You have a fuel pump whizzing that fuel round the rail independent of the gas cap & independent of gravity feed & independent of starter & anything else suggested here. My question is why would fuel level make the least diff?

    Baffling.
     
  15. Gort

    Gort Senior Member Supporting Vendor

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    Because all pumps work better with a greater pressure head. It just may take longer for the fuel to get to the injector when there's less pressure head, and if the fuel pump is marginal due to design or degradation, this small difference may account for the starting issue.
     

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