Gas mileage
09-21-2009, 12:18 PM
#1
Gas mileage
I was wondering if I'm getting a good MPG ratio.... If I make a drive from CT to RI cruising at 70 MPH about 1hr. 30min trip, should my fuel needle be moving from 3/4 of a tank to 1/2 of a tank on one trip???? car has 161,000 miles......I mean i did fuel system cleaning(not that bottle stuff), changed fuel filter, cleaned throttle body, thinkin bout doing 02 sensors, any other suggestions???? do you guys think this is reasonable
09-21-2009, 12:29 PM
#2
fuel gauges are almost always inaccurate...... unless you have a real fuel mileage figure (fill up, reset trip, drive, fill up again, divide miles by gallons) it doesn't say anything. case in point my brother's camry (which i now drive) said over half tank with 256 miles driven, then corrected itself to "empty" 70 miles later.
09-21-2009, 12:35 PM
#3
fuel gauges are almost always inaccurate...... unless you have a real fuel mileage figure (fill up, reset trip, drive, fill up again, divide miles by gallons) it doesn't say anything. case in point my brother's camry (which i now drive) said over half tank with 256 miles driven, then corrected itself to "empty" 70 miles later.
09-21-2009, 12:37 PM
#4
agreed. I get about 100 miles, from the time I fill up (completely top off), until the needle moves. then I get about 30 or so miles, and I am on 3/4. 70 miles later, I have "1/2 tank".
I get about 25 mpg, est, based on gps calculated mileage. Not the most accurate, but better than the 15 est I get based off my inaccurate speedo (says 65 @ approx 60).
I get about 25 mpg, est, based on gps calculated mileage. Not the most accurate, but better than the 15 est I get based off my inaccurate speedo (says 65 @ approx 60).
09-21-2009, 12:39 PM
#5
agreed. I get about 100 miles, from the time I fill up (completely top off), until the needle moves. then I get about 30 or so miles, and I am on 3/4. 70 miles later, I have "1/2 tank".
I get about 25 mpg, est, based on gps calculated mileage. Not the most accurate, but better than the 15 est I get based off my inaccurate speedo (says 65 @ approx 60).
I get about 25 mpg, est, based on gps calculated mileage. Not the most accurate, but better than the 15 est I get based off my inaccurate speedo (says 65 @ approx 60).
09-21-2009, 01:16 PM
#6
09-21-2009, 01:21 PM
#7
You don't know that unless you calculate your gas mileage. The gas gauge isn't linear. Why don't you calculate the gas mileage properly and then come back for diagnosis/discussion/etc. I mean, at this point, you don't even know if you're getting bad gas mileage or not..
Well yea the next time I fill up i was going to reset my trip meter and see what I get a on a full tank, but it juss seems like it went down since i bought the car that's all I'm really emphasizing
09-21-2009, 02:35 PM
#8
nono, the light didn't stay on... the needle read half-tank at 250 miles and SUDDENLY dropped to empty just 70 miles later. i think his sending unit is crudded up, and only "updates" the needle if i go over a big speedbump or something. so i really can't look at the gauge and say "oh i have this much gas left" because i know that the thing tends to get stuck then move alot all at once. i just know not to push it much further than 300mi/tank on that particular car. man i miss the days of 450 mile tanks on the maxima....
Last edited by CapedCadaver; 09-21-2009 at 02:38 PM.
09-21-2009, 03:07 PM
#9
I was wondering if I'm getting a good MPG ratio.... If I make a drive from CT to RI cruising at 70 MPH about 1hr. 30min trip, should my fuel needle be moving from 3/4 of a tank to 1/2 of a tank on one trip???? car has 161,000 miles......I mean i did fuel system cleaning(not that bottle stuff), changed fuel filter, cleaned throttle body, thinkin bout doing 02 sensors, any other suggestions???? do you guys think this is reasonable
Man this reminds me of those standardized test math problems from 8th grade. At what time will subject "A" reach point "B" and how much gas will he have left? Lol!
09-21-2009, 03:51 PM
#10
nono, the light didn't stay on... the needle read half-tank at 250 miles and SUDDENLY dropped to empty just 70 miles later. i think his sending unit is crudded up, and only "updates" the needle if i go over a big speedbump or something. so i really can't look at the gauge and say "oh i have this much gas left" because i know that the thing tends to get stuck then move alot all at once. i just know not to push it much further than 300mi/tank on that particular car. man i miss the days of 450 mile tanks on the maxima....
Oh I understand your statement now!!!
09-21-2009, 03:52 PM
#11
09-21-2009, 08:34 PM
#12
I did some math and my tank has 4 gallons when the light comes on. I was getting around 270 miles a trip and every time I filled up I could only put in 14 gallons in it with the needle past the "E" lol
09-21-2009, 10:44 PM
#13
if trip begins with full tank, then Miles driven / gallons filled = mpg.
my (VE-5) maxima got about 26-28 mpg at an average speed of 80 mph....and better mileage in 4th than 5th gear for some reason.
so you're saying you have an 18 gallon tank? 
my (VE-5) maxima got about 26-28 mpg at an average speed of 80 mph....and better mileage in 4th than 5th gear for some reason.
09-22-2009, 06:00 AM
#14
Senior Member
Join Date: Nov 2004
Location: Austin, TX
Posts: 333
I believe he's simply referring to that if his gauge hits 'E' then based on 270miles/14gallons = 19.28MPG that he should still be able to drive 77.14miles before running out of gas... it's a great thing to know about your car especially if you find yourself without a gas station around...
09-22-2009, 06:55 AM
#15
that's weird that you would get better mpg in 5th unless you have so little torque at the 5th gear cruising rpm that you had to apply a ton more throttle than you would in 4th. is this with or without VTCs grounded?
09-22-2009, 01:45 PM
#17
well fsm says 18.5... one time i put in 18.2. talk about running on fumes haha.
that's weird that you would get better mpg in 5th unless you have so little torque at the 5th gear cruising rpm that you had to apply a ton more throttle than you would in 4th. is this with or without VTCs grounded?
that's weird that you would get better mpg in 5th unless you have so little torque at the 5th gear cruising rpm that you had to apply a ton more throttle than you would in 4th. is this with or without VTCs grounded?
09-22-2009, 03:57 PM
#18
grounding the VTCs either reduces low end power or high end power.... at this point i forget which, in order to make the clack stop or reduce. but if it reduces low-end power then it's possible that the engine would be less fuel efficient at low RPMs than it would be with functional VTCs, which could theoretically lead to running a lower gear resulting in better mpg..... but if grounding the vtc's affects topend power then it must just be a conincidence that he was getting better MPG in a lower gear.
Last edited by CapedCadaver; 09-22-2009 at 04:01 PM.
09-22-2009, 04:06 PM
#19
grounding the VTCs either reduces low end power or high end power.... at this point i forget which, in order to make the clack stop or reduce. but if it reduces low-end power then it's possible that the engine would be less fuel efficient at low RPMs than it would be with functional VTCs, which could theoretically lead to running a lower gear resulting in better mpg..... but if grounding the vtc's affects topend power then it must just be a conincidence that he was getting better MPG in a lower gear.
09-22-2009, 04:17 PM
#20
Senior Member
Join Date: Nov 2004
Location: Austin, TX
Posts: 333
You might wanna check your tranny fluid if it's taking that long to shift... sounds like there's not enough ATF for the TC to operate properly... In which case if you've been running that way for even a little bit, your tranny is prolly on it's way out no doubt...
09-22-2009, 04:31 PM
#21
checked my fluid regularly but one time i checked it, and it smell like it was burning and black in color, i was gunna do a tranny flush but i hear if u suspect the trany is failing and u do a flush it will fail after the flush is over...
09-22-2009, 04:36 PM
#22
for one thing, i noticed that at very high speed, my VG5 felt like it pulled harder in 5th than in 4th (like at 90+mph), i guess because once I hit 90 in 4th (around 4600rpm) the torque has fallen off
Last edited by CapedCadaver; 09-23-2009 at 06:54 AM.
09-22-2009, 04:50 PM
#23
eh not necessarily failing. tps can be improperly adjusted. do you put it in power mode, normal, or comfort? if it's in power mode, it will always shift late, by design. but i was moreso referring to on a manual, where the gears have a true rpm-to-mph mappings, where an automatic is sort of 'flexible' because of the torque converter, which might make the effect i was describing a little less prevalent.
for one thing, i noticed that at very high speed, my VG5 felt like it pulled harder in 5th than in 5th (like at 90+mph), i guess because once I hit 90 in 4th (around 4600rpm) the torque has fallen off
for one thing, i noticed that at very high speed, my VG5 felt like it pulled harder in 5th than in 5th (like at 90+mph), i guess because once I hit 90 in 4th (around 4600rpm) the torque has fallen off
09-22-2009, 04:55 PM
#24
have you pulled TCU codes yet? unless you are SURE the tranny is slipping or physically damaged (which will definitely ruin MPGs haha) then always start with the cheap/free diagnoses first.
09-22-2009, 05:02 PM
#25
At school I've hooked up the solus from snap-on, and ran codes and everything seems to be ok, but I will do the the tranny flush before I finally say that its damaged
09-22-2009, 05:13 PM
#26
09-22-2009, 05:17 PM
#27
well I hooked it up to the lil nissan adapter under the fuse box since our cars aren't OBD-II, and ran the transmission codes through the scanner.... what way do you check TCU?? wouldn't it be the same way regardless
09-22-2009, 05:25 PM
#28
i never have myself (tranny died without warning, so i never had a reason to run codes on it). but having never used a fancy hookup scanner thingy, i wasn't aware that you could just run codes that way, but looking at the FSM it does show that you can do alot of stuff via consult.
09-22-2009, 05:33 PM
#29
i never have myself (tranny died without warning, so i never had a reason to run codes on it). but having never used a fancy hookup scanner thingy, i wasn't aware that you could just run codes that way, but looking at the FSM it does show that you can do alot of stuff via consult.
09-22-2009, 05:37 PM
#30
yea you can watch the tranny shift on the scanner and all types of stuff like I was running a test while driving, and the scanner would say that the tranny was changing gears, but in reality it wasn't that why Ino all the computer controls for the tranny are good i just thinks it's mechanically gone... where do I geta FSM from???
but there is usually a slight delay between when the electronics indicate a gear change and when the new gear is actually fully engaged. but if, in your case, it is truly excessive, then yea maybe you might need a new tranny. as always... have you got a video of its behavior?
09-22-2009, 05:47 PM
#31
www.boredmder.com
but there is usually a slight delay between when the electronics indicate a gear change and when the new gear is actually fully engaged. but if, in your case, it is truly excessive, then yea maybe you might need a new tranny. as always... have you got a video of its behavior?
but there is usually a slight delay between when the electronics indicate a gear change and when the new gear is actually fully engaged. but if, in your case, it is truly excessive, then yea maybe you might need a new tranny. as always... have you got a video of its behavior?
09-22-2009, 10:02 PM
#32
I believe he's simply referring to that if his gauge hits 'E' then based on 270miles/14gallons = 19.28MPG that he should still be able to drive 77.14miles before running out of gas... it's a great thing to know about your car especially if you find yourself without a gas station around...
Originally Posted by Jcarryl
Yah the 3rd Gen's have an 18.5 gallon tank.
Originally Posted by Caped Cadaver
well fsm says 18.5... one time i put in 18.2. talk about running on fumes haha.
that's weird that you would get better mpg in 5th unless you have so little torque at the 5th gear cruising rpm that you had to apply a ton more throttle than you would in 4th. is this with or without VTCs grounded?
that's weird that you would get better mpg in 5th unless you have so little torque at the 5th gear cruising rpm that you had to apply a ton more throttle than you would in 4th. is this with or without VTCs grounded?
It's been a while since i was separated from my maxima, and i'm starting to forget things slowly. 
(but we'll be reunited in november.)I grounded my VTC's, but it hasn't made a difference in gas mileage. I've put a quick disconnect coupling on my grounding wires and tested it out either way to no conclusion.
Originally Posted by CapedCadaver
my VG5 felt like it pulled harder in 5th than in 5th
wat.
09-23-2009, 04:47 AM
#33
Senior Member
Join Date: Feb 2009
Location: Columbia SC
Posts: 2,284
Well its good to know that I have an 18.5 gallon gas tank, I kinda confirmed this when my gas hand was on E, and then went below E. I was so afraid of running out of gas that day. I filled it to get about 9 gallons, which I though would put the gauge over the halfway mark. And to my surprise I only got half a tank! So I said wow, it really is an 18gallon tank, and the whole time I only thought it was a 14 gallon tank! Also I think if you use plus or premium gas when taking long trips that you can get more miles per gallon, because in my opinion it the plus and premium gas seems to make the car run smoother and better then certain brands of regular gas. Ive noticed that I get better mileage with plus or premium than with regular in my GXE, and it seems to run alot better and quieter!
09-23-2009, 06:17 AM
#34
Well its good to know that I have an 18.5 gallon gas tank, I kinda confirmed this when my gas hand was on E, and then went below E. I was so afraid of running out of gas that day. I filled it to get about 9 gallons, which I though would put the gauge over the halfway mark. And to my surprise I only got half a tank! So I said wow, it really is an 18gallon tank, and the whole time I only thought it was a 14 gallon tank! Also I think if you use plus or premium gas when taking long trips that you can get more miles per gallon, because in my opinion it the plus and premium gas seems to make the car run smoother and better then certain brands of regular gas. Ive noticed that I get better mileage with plus or premium than with regular in my GXE, and it seems to run alot better and quieter!
the most I have been able to put in my tank was 15 gallons and it over filled and gas leaked on to the floor, I cant really believe this thing holds approx. 18 gallons
09-23-2009, 06:56 AM
#35
haha i fixed it
09-23-2009, 07:54 AM
#36
09-23-2009, 11:46 AM
#37
Heres the link to the video kinda blurry, but it's all I can do
http://pictures.sprintpcs.com/share....tate=RETRIEVED
http://pictures.sprintpcs.com/share....tate=RETRIEVED
09-23-2009, 02:30 PM
#38
Member
Join Date: Sep 2009
Posts: 121
so far in half a tank i would get like 204 miles using the OD all the time. I go to San Francisco all the time its about 45 miles each way. I am going to Disneyland next month so it will be interesting to see if I can go one way on a full tank....
09-23-2009, 05:17 PM
#39
Senior Member
Join Date: Sep 2007
Posts: 1,042
i get 19mpg with the a/c on and "aggressive" driving in the city.
but was VERY surprised to get 27mpg on the highway.
while with the a/c on doing 70mph sometimes 80mph.
and the gas hand usually drops when there's like 3 gallons left before the gas light comes on.
i have to admit though the gas lights in these cars are pretty good and accurate.
everytime it starts comes on i put like 3 gallons in and the gauge goes to the 1/4 mark.
and i noticed i have'nt ran out of gas in this car before.
4 gal. of reserve come in handy.lol.
but was VERY surprised to get 27mpg on the highway.
while with the a/c on doing 70mph sometimes 80mph.
and the gas hand usually drops when there's like 3 gallons left before the gas light comes on.
i have to admit though the gas lights in these cars are pretty good and accurate.
everytime it starts comes on i put like 3 gallons in and the gauge goes to the 1/4 mark.
and i noticed i have'nt ran out of gas in this car before.
4 gal. of reserve come in handy.lol.
09-23-2009, 05:19 PM
#40
Heres the link to the video kinda blurry, but it's all I can do
http://pictures.sprintpcs.com/share....tate=RETRIEVED
http://pictures.sprintpcs.com/share....tate=RETRIEVED