ECM "economy mode" when fuel light flashing?

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Jammer

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I did a quick search so don't flame me if it's be discussed here already!!!

Anyway, on Sat. I got my 05 FJR out for the first time this year, wanted to run the old gas out of it before filling. Got to the dealer open house I was attending & a friend had his dyno there. When I got there the fuel light was flashing and the trip had flipped to distance since the light came on - about 1 mile. Ran the FJ on the dyno, and it wouldn't rev out - max 6000 rpm in 5th, not much better in 4th. HP #s - 79 in 4th, 98 in 3rd, no run for 5th. I didn't know why, neither did the dyno operator. Suffering from "delayed intelligence", about 1/2 hr later I thought that maybe the ECM goes into a sort of "economy mode" when the fuel light comes on, to prevent the rider from wailing on it to maximize fuel range. So, I filled up, couldn't run it the same day (he was too busy showing other riders how weak their bikes were!). On the way home I ran it through the gears - no prob - 9000 rpm in 5th into a slight headwind, 9300 with a slight tailwind.

Next day - ran it on the dyno - 119.97 in 4th, 120.1 in 5th. I'm happy - it'll still do a wheelie & get a speeding ticket (if caught, anyway).

So, does anyone know more about this than I do? I checked my owner's manual & shop manual - not a word anywhere.

I mean, it seems logical to maximize range when the light starts flashing - I've just never seen anything, anywhere written on it.

Please enlighten me, oh gurus of FJRforum.com!

 
You said yourself there was old gas in the tank. I would believe the old gas was causing the problem. There isn't any change to the way the ECU is operating when the fuel light comes on that I know of.

 
I hear what you are saying, but on the way there I ranit up to 9000+ rpm in fourth and it was working fine then.

Like I said, I just don't know.

 
I hear what you are saying, but on the way there I ranit up to 9000+ rpm in fourth and it was working fine then.
Like I said, I just don't know.
Yeah, but on the way there you weren't loading it up to find the maximum horsepower, like the dyno does.

 
Hmmm.

Whenever my fuel light starts flashing, I go into economy mode, so I have never tried to go over 6 grand in that state, but I have gone 47 miles (on CA gas), which I have never done with the first gallon in my tank.

It would be a good feature, if it actually works that way. You'd think we'd know about it by now. I don't think it was about old gas.

 
I hear what you are saying, but on the way there I ranit up to 9000+ rpm in fourth and it was working fine then.
Like I said, I just don't know.
Yeah, but on the way there you weren't loading it up to find the maximum horsepower, like the dyno does.
Actually, running it up to 9000 rpm on the road is exactly like a dyno run for max hp like a dyno. In fact, it's probably working a little harder due to the wind resistance. It topped out the other day (with a tailwind) at 245 km/h @ 9300 rpm (240 @ 9000 into the wind), but the speed on the dyno readout, obviously no wind resistance, was 260km/h.

 
Yamaha does not brag about that 'feature' anyplace. Usually they make sure you know that they have thoughtfully added a convenience item.

[Guess]

What are the chances that the tank wasn't venting? If the tank was raised, what are the chances the fuel pickup was above the fuel level? Was the whole motorcycle level? Is there a chance that the fuel was foaming since the level was so low and the Gen I has a fuel return to the tank?

[/guess]

 
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The light is flashing again, so I'll go out & run it on the "asphalt dyno", to see if the condition repeats. Might take me a few days to fit it in, but I'll report back when I do.

 
and let us know what 9000rpm results in mph wise....in fifth gear........ :rolleyes:

 
Anyway, turns out I was just pissin in the wind. Took it out last night with the light flashing and it ran through the gears to redline, no problem - except later when I had over 30 miles on it since the light came on, when I hit it hard the bike would surge ahead & then I would get fuel starvation as it sloshed around the tank. Other than that, it worked fine.

So, no special features to report - I apologize for any confusion here.

As for the speed in mph @ 9000 in 5th, about 150.

 
on CA gas my 07 gets a little "crabby" when it gets very low. Starts with a bit of a "miss" sometimes when it's real low. I ride it daily so no gas ever sits more than two weeks. My suspect was vapor lock. I didn't pop the cap and see because I was headed over to get a fillup when it did this.

Didn't notice any power difference according to the "@ss Dyno".

 
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