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Discussion Starter #1
Ok, the 94 up cars basically have two low fuel lights. The first comes on and says low fuel. The second comes on and says check guages. Does anyone know how much fuel is left in the tank when the check guages light comes on? There is a gas mileage issue here so thats why I'm asking to get a the correct figure on my mileage.
 

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Voice/Data Guru
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:leftrightOn my 96 I belive its 3 gallons left when the light comes on

and i might add she got 24 to 25 MPG On a recent 1500 mile trip :)
 

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Ok, the 94 up cars basically have two low fuel lights. The first comes on and says low fuel. The second comes on and says check guages. Does anyone know how much fuel is left in the tank when the check guages light comes on? There is a gas mileage issue here so thats why I'm asking to get a the correct figure on my mileage.
I'd like to know this too, as I don't have a VMM in my car.

speaking of the VMM, what is needed to swap one in? the VMM itself and the various reservoirs with the sensors?
if so, what reservoirs are needed?
 

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There's a lot of play in the gas gauge measurement...

No two cars are going to be the same, unless it's random chance.

There is a 10% range on each component in the circuit, and the variation in your voltage regulator as well.

Best you can do is fill it up, run it out, and refill it from the same pump; and if the outside temperature is different, then that's +/- a few percent...

I drive the same drive everyday, 4 days to a tank, and have been tracking mileage for over 5 years and 100k miles; It's really amazing the variation in gas itself. Winter gas sux bigtime!

I've learned to tell when the oil is ready to be changed, watched my tranny die, and killed two o2 sensors, as well as who sells the worst and best gas, and who's pumps are ripoffs. (For me, My local Exxon rules; but different stations are different... :mad: ) All from gas mileage changes.

My Black and Red Cougars read totally differently on the gauges, pretty much all of them. I do finally have the speedos reading right, tho...it took a while...A gps is a great reference for speedo use. And you have to correct your gas mileage for speedo/odo errors, otherwise, your numbers are wrong...


Back to topic:

If you really need to know where the lights are on your car, put a gas can in the trunk and go find out; be warned, you may have to use the schrader valve on the rail to vent air out of the fuel system if you drain it to the last drop. :D

Go all the way to empty, put in a gallon, and go to the gas station...see where the light goes off as you fill it up.
 

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Discussion Starter #6
Ok so lets say its 3 gallons left just for a estimate. I recently got 22mpg on trip with my mods. It needs a good run through on the maintenance side of things like plugs, seafoam (which has never been done but i hear it can affect your seals and my valve seals are already seeping a good bit), fuel filter, etc. Also it has no tune locked in but I do have my xcal2 ready to be sent back in for retune its just that with the little boy there is always something else to spend the 80 something dollars on.

I just thought that it should have been better than that.
 

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I'd like to know this too, as I don't have a VMM in my car.

speaking of the VMM, what is needed to swap one in? the VMM itself and the various reservoirs with the sensors?
if so, what reservoirs are needed?
its already got the pigtails, so all you need is the VMM, and coolant and washer reservoirs.
 

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Discussion Starter #9
Its not that far behind on things. Maybe about 8 months or so. Havent took the time to do anything but oil changes since my son was born.
 

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The Parts Guy
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I just want to make sure that you know that the amount of fuel left in the tank when the light comes on has nothing at all to do with calculating fuel mileage. It sounds like you're taking the tank size, minus the amount left in the tank when the light comes on, and dividing that into the number of miles driven until the light comes on. That wouldn't be very accurate. What you want to do is fill the tank and reset your odometer. Drive the car. The next time you fill the tank, divide the number of miles driven by the amount of fuel it takes to refill the tank.

-Rod
 

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exactly, if you asking about this so you can more acurately calculate your fuel mileage then forget about the idiot lights. They are of no help to you.

1) Fill gas tank
2) Reset Odometer
3) Drive
4) Refill Tank
5) Divide # miles driven by the # of gallons it took to refill the tank.

There's your average fuel economy for the trip.
 

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exactly, if you asking about this so you can more acurately calculate your fuel mileage then forget about the idiot lights. They are of no help to you.

1) Fill gas tank
2) Reset Odometer
3) Drive
4) Refill Tank
5) Divide # miles driven by the # of gallons it took to refill the tank.

There's your average fuel economy for the trip.

thats pretty much how most people do it, and works for that particular trip......except that if you do a good percentage of city driving ( > ~20%) of the total miles, the fuel economy calculation will not be as accurate as it could be, because it will not converge until you drive several tankfuls to get an average......even if its the same route you take everyday, severe traffic one week will skew the results....or if your lazy (like me) and dont get up early enough and rush to work one week, but get your act together the next week and take it nice n easy.....things like this all have an impact

for mostly highway driving (<10% stop-n-go), its pretty accurate to calculate long-trip fuel economy
 

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I don't measure short trips under different driving conditions i just want to know what kind of real world mpg i'm averaging over a tank of gas. That includes all kinds of driving as well as just idling burning gas.

What i suggested would certainly be more accurate then any method thats factoring in when the idiot light comes on.
 

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hat i suggested would certainly be more accurate then any method thats factoring in when the idiot light comes on.
oh of course....i was just throwing that out there so other people can get a good gasp of things :)
 

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Discussion Starter #15
Ok thanks for the input. When I get the chance to do so I will. I understand what you are saying it and that does seem like it would be a good bit more accurate. Oh by the way I noticed something about my injectors. If you guys remember I attempted the 32v swap and pretty much failed for whatever the reason was. I then let a few guys put the 16v back in for me and get the car running because I was at my wits end sharing a civic with my wife for over a year working two different shifts. Anyways I noticed after all this time that one of the injectors is more orange where as all the rest are yellow. I don't remember it being like that before but I am not sure. Anyways my question is could that one injector have a different flow rate than the rest?
 

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it would have to be a different injector for it to have a different flow rate....any part # on it that you can see? ...if not, then the only way to tell would be to hook up a real-time scanner and look at the long term fuel trims for that side of the engine while its running....if it's a 'larger' injector, the LTFT for that side will be less than 1.00, and if its 'smaller' injector, the LTFT will be above 1.00
 

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Another way to check remaining volume is to measure the miles to the station after the light comes on and then note how many gallons to fill it to the brim. Just today on my commute home it came on and I drove 20 miles to my favorite station and it only took 15.1 gallons. The capacity is 16.5+/- so with my average mileage at 20 MPG it means my light comes on with 2.5+/- gallons in reserve. Caution!!! no two vehicles are the same. My '03 Explorer light comes on and you had better drive real easy to the station.

My 0.02
 

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Anyways I noticed after all this time that one of the injectors is more orange where as all the rest are yellow. I don't remember it being like that before but I am not sure. Anyways my question is could that one injector have a different flow rate than the rest?
My stock injectors were yellow, and the replacements I bought from autozone were orange (same flow rate). Had them on for two years now.

Stephen
 

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Another way to check remaining volume is to measure the miles to the station after the light comes on and then note how many gallons to fill it to the brim. Just today on my commute home it came on and I drove 20 miles to my favorite station and it only took 15.1 gallons. The capacity is 16.5+/- so with my average mileage at 20 MPG it means my light comes on with 2.5+/- gallons in reserve. Caution!!! no two vehicles are the same. My '03 Explorer light comes on and you had better drive real easy to the station.

My 0.02
Your confused. Unless you've put a fuel cell in it's an 18 gallon tank.
 
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