Last post on Aug 19, 2002 at 4:49 PM
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Nissan Sentra, Engine
#6 of 7 Re:How is your heat??
Aug 19, 2002 (3:38 pm)
"Does your car have a temp gauge? If so, is it low, high, normal?"
Normal in any case. I have never had problems with temp.
"I would suspect the Check Engine Light (CEL) to come on."
I hope it will not. No, not yet.
"Does the car pull to one side?"
Yes, a little bit. But I have heard that in US it should be so for better water draining... I mean that roads have "^" profile.
"How about coast down?"
I didn't pay attention, but I didn't see anything wrong... Of course I can be mistaken...
"If an automatic"
Yes, it is.
"is the overdrive (O/D) turned on?"
No, but I have such an opportunity. I used it a few number of times for last year.
"Also, if your car has a locking torque converter, if it doesn't lock up it could cause poor fuel economy with giving any driveability issues"
I think I do not have it. Sentra is rather cheap car...
"Are you running to redline before you shift?"
No, moreover, it is difficult. This engine has a max torque at 2400 RPM, so transmission try to make engine use these RPMs...
"or the other extreme, do you "short shift" at low RPMs?"
I think, no. I didn't change my driving style, and I have never had such problems on other cars.
"I have to ask the obvious question, are you calculating MPG based on the tank capacity or how many gallons you put in the vehicle?"
It will be easier to describe my calculation scheme . I fill my tank "by edges" and reset the odometer (sorry, if I mix up with names). When I need to fill the tank again, I can see, how many gallons (N) should I fill at THIS, not THAT time and how many miles (M) had I driven. I just divide M to N and result is ready - about
22-23 mpg on highway and 20-21 mpg in city.
BTW: Today I was in another (third) dealership again. I got an answer that they saw 27-28 mpg on highway (even if this is true, it should be 33) and I am not to complain.
Aug 19, 2002 (4:49 pm)
If the car is an Automatic, then it is shifting on it's own.
I would be suprised if it did not have a locking torque converter, as most cars today do, even the cheap ones. Especially since cheap cars are often sold on their economy merits.
I am curious how the dealership is measuring fuel economy, since I doubt they are driving a significant distance.
They measure fuel economy the same way the Federal government does. When the EPA measures fuel economy, they don't measure how much fuel is used. Instead, they run the car on a dyno and measure the components of the exhaust gas, plug this into a formula along with other values such as the weight, frontal area, drag coefficient, and perhaps the phase of the moon (just kidding about the phase of the moon thing) and then the derive the fuel economy.
However, this really isn't real world, as there are many other factors that impact fuel economy, such as low tire pressure, head or cross winds, how much you carry in the car (a small car is much more suspect to any extra weight you carry in the car), that Yakima bike rack you might have on top really provides a lot more drag.
Even my 1987 Buick LeSabre, at over 3600# has wildly varying fuel economy. I have seen from 19 MPG to 31 MPG over the course of the past 14 months. But the long term average is right at 23 MPG.
I suggest filling up, letting the pump stop at the very first stop and then keeping a log for 4 weeks. Record you mileage at the beginning of the period. Indicate the types of trips and distance, such as stop and go, interstate/freeway, or other significant characteristics, what kind of traffic, weather and what not. And of course, record every time you add fuel and the amount.
At the end of the four weeks, fill up at the very same pump, and again stop the pump on the first automatic shutoff.
Then add up the number of gallons and the total number of miles travelled.
I suspect this will be more accurate as you will have a much larger sample.
Then look at your MPG and compare that with the type of driving you do.
In my case, four weeks is about 2500 miles, so I get a pretty good sample. I find I use about 105-110 gallons of fuel per month.