Help me calculate my Aspire's MPG

[eljefino]

The upshift light in my manual transmission saturn IS an emissions control device according to the EPA. Its presence is a CAFE thing and GM gets ~1/10 of an MPG "free" for having the stupid light.

I would need a shop manual for a 97+ model year saturn (when they introduced the low fuel light) to see if that light would set a code, but I bet NOT. Maybe a "service wrench" which is NOT emissions related.

If the upshift light burns out, the car WILL set a quad driver (computer output transistor current) error code and light the check engine light.

Incidentally, a burned out CEL will also set a code but you'd need a scantool to know it.

I have driven with a failing in-tank fuel pump on a dodge dakota and it will run and even make good power with wildly varying/low fuel pressure as measured at the fuel rail. Rated at 40 psi I was only getting 20psi max and it would stall at 0-5 psi when idling if the pump cut out. I think that guy is exaggerating WRT misfires.

 

[kreigle]

quote:

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Originally posted by brianl703:

quote:

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Originally posted by kenw:
If it is required to meet emissions, why isn't it covered?

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And why, if it's required, are there many vehicles made since the early 80s without a low fuel light?

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And if it is unleaded/catalytic emissions related, why do all Saabs from the '60s have one?

 

[kenw]

quote:

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Originally posted by kreigle:

quote:

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Originally posted by brianl703:

quote:

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Originally posted by kenw:
If it is required to meet emissions, why isn't it covered?

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And why, if it's required, are there many vehicles made since the early 80s without a low fuel light?

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And if it is unleaded/catalytic emissions related, why do all Saabs from the '60s have one?

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that's easy: running out of gas in Sweden IS dangerous. You might get attacked by a moose.

seriously, there's no reason to think that other makers didn't use it as a true idiot light. Mr H's postulation is that Toyota used it for something other than an idiot light. that's what I'm having a hard time with...

 

[brianl703]

quote:

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Originally posted by eljefino:
The upshift light in my manual transmission saturn IS an emissions control device according to the EPA.

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Does it have a tach? I wonder if a tach allows them the same savings that an upshift light does..

The PCM in my 1988 Mustang has the ability to control an upshift light, it's just not implemented. There is a place on the circuit board for a driver transistor for the light, and the software is already there for it, although it's disabled.

But that Mustang has a tach, perhaps that's why it wasn't implemented.

 

[Bob Woods]

"Always keep the TOP half of your fuel tank full!"

That is one stupid statement, and quite impossible to do. Always keep the bottom half full is more realistic. I think its a good idea to fill up when your gas gauge reads half, that way if you get dirty or otherwise bad gas its diluted by half. And thats better than having 25 gallons of bad gas in a 27 gallon tank.

 

[MN Driver]

you've got me imagining gravity being upside down in a gas tank, strange.. I think that if you've got 1/4 tank or more everything has got to be okay, although I agree with recommendations of keeping at least of 1/2 tank in the winter to prevent water in the tank, which is something i've seen happen and it brings sales of fuel de-icer that would usually not be needed(I've never bought any, but I know friends with 1/8 who needed it in the winter). I usually fill up around 1/4 of a tank, but lately i've just filled up when i've hit the point where $20 would fill it fill, which is between 1/4 and 1/2 depending on the price of gas at the time.