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Old 11-19-2012, 01:13 AM   #1
b16h22
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Default Does low fuel indicator adjust ecu?

When the low fuel light comes on does it in any way adjust the ecu to compensate?
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Old 11-19-2012, 01:26 AM   #2
Uncle Scotty
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mmmmm...good question...first time ive seen it in years
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Old 11-19-2012, 08:07 AM   #3
talvai
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Not sure with older models but 08+ don't see why not. You guys have Si drive which adjusts throttle response, etc. Don't see why when light comes on you send a signal to ecu to change SI drive to another map.

Not to sound like a douche but why? Why not just put gas before you get that low? Just saying.
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Old 11-19-2012, 09:39 AM   #4
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Realistically i don't think it would and here is why. That anti slouch feature which keeps the fuel gauge from bouncing all over the place, would affect it. The gauge is a median, an average of the high and low point of fuel in the tank and if they did have something like that it would be baaed on pressure not level . Also if your fuel pump was going bad, it doesn't change the map it blows up your motor. And lastly its called a dummy light for a reason. These are not facts just general knowing how they engineer cars.
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Old 11-19-2012, 06:48 PM   #5
talvai
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Quote:
Originally Posted by ringlander View Post
Realistically i don't think it would and here is why. That anti slouch feature which keeps the fuel gauge from bouncing all over the place, would affect it. The gauge is a median, an average of the high and low point of fuel in the tank and if they did have something like that it would be baaed on pressure not level . Also if your fuel pump was going bad, it doesn't change the map it blows up your motor. And lastly its called a dummy light for a reason. These are not facts just general knowing how they engineer cars.
Think op means when light is on, which means you can tap that signal and use it to do something regardless of how much gas is left. So in theory yes you could swap maps no problem. all it is, is basic electronics and programming nothing special. That being said its like i said is it worth the work. If op is just trying to do it so he can gain few extra mpg till he gets gas not worth the work. But that's just my opinion, each his own
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Old 11-19-2012, 06:58 PM   #6
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Rumor is the ecu trims back full boost psi around 1/4 tank. No clue if that's true or not, only digging into FACTORY ECU map will tell you.



And that's how stupid rumors stay alive!
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Old 11-20-2012, 06:55 PM   #7
b16h22
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Reason i'm asking is during my last session at the track over the weekend at Autoclub Speedway I was about out of gas and my car started cutting out, but only in 4th gear. It almost felt like the timing was getting pulled back or maybe like mentioned it switched to the Intelligent mode mapping for a few seconds. And this wasn't happening every time I was in 4th, but once a lap and in nearly the exact same spot which threw me off even more! There doesn't seem to be any mechanical issues. Unfortunately I wasn't data logging. The car was running extremely strong other than in those few moments and it hasn't re-occurred since. It's a stage 2 setup with Cobb's OTS stage 2 map.

Last edited by b16h22; 11-20-2012 at 07:09 PM.
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Old 11-20-2012, 07:08 PM   #8
the suicidal eggroll
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I have never seen any evidence to suggest that the car uses the low fuel signal for anything other than illuminating the light.


99.9999% chance your cutting out problems are from starving the pickup while cornering with low fuel. Either autocross with more fuel in the tank (at least 1/2 tank), or install a surge tank and external pump.
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Old 11-20-2012, 07:17 PM   #9
ScubyPhilly
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Quote:
Originally Posted by the suicidal eggroll View Post
...99.9999% chance your cutting out problems are from starving the pickup while cornering with low fuel...
Exactly what I was thinking. Especially when I read, "[At] the same spot [of the track.]"
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Old 11-20-2012, 07:26 PM   #10
b16h22
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this was on the road course and it was about 500-600ft i'd say after a very hard turn (turn 9) so you guys might be right. actually i'm hoping you're right!
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