I need to calibrate my RPM, since it is always at 900-1000, and i think thats why it eats my gas? maybe i should leave it as is?

What do you say daniel B. martin?

 

I'd like to help but don't understand your problem. Is your tachometer inaccurate? Is it accurate and your engine is unable to rev faster than 1000 rpm? What is your present fuel consumption, and what do you think it should be?

 

Currently my fuel consuption on full tank is 135 miles!!! And I do not know what to do where to start looking for this problem, I drive in city 100%, it used to be like 160-180 miles on tank and it was fine with me. My car has new parts:
spark plugs
fuel filter
air filter

currently has 40k miles and it is 1997 maxima gle.

Also about RPM, when you start up its 1400-1500 and after warming up it goes down to 1000-1100 and i remmy you had discussion where you said it should be 700-750 at iddle.

Engine works fine.

Any advices from you?

Thanks in advance!

 

Whoa..160 miles on a full tank? Do you have any extra weight in your car? Do you punch it a lot?
I usually get around 300-320 from a full tank of gas..
There is something amiss here...Maybe your idle speed is to high but i don't know if that would make such a significant difference. I'll let Daniel answer that one.

 

Thank you for the clarification. It gives a much better picture of your car's behavior.

Miles per tank is a crude measure of fuel usage. Miles per gallon is more accurate, especially when based on fuel consumption over a span of thousands of miles. However, 135 miles from an 18.5 gallon tank is awful, even in city driving. Something is wrong. Your car is using too much fuel. Four possibilities exist:
- you are burning it
- you are leaking it
- someone is stealing it
- you switched to gasohol


Burning it...
- fuel injectors are sticking open
- "tired" Oxygen Sensors
- bad fuel pressure regulator
- obstructed fuel return line
- bad Engine Coolant Temperature Sensor
- stuck-open thermostat (engine never goes into closed-loop mode)
- transmission defect (never shifts into fourth gear)


Leaking it...
Search for fuel leaks by sight and odor. However, some fuel leaks are so
tiny that they escape the human senses. One way to find them is to have
your mechanic use his exhaust gas analyzer. Switch the tester to HC
(hydrocarbons) and then pass the probe along the entire fuel system,
starting at the fuel tank, forward along the fuel lines, past the filter,
all around the engine, then along the return line and back to the tank.
The tester is far more sensitive than the human eye or nose. When the
probe passes near a tiny leak the reading will abruptly increase.


Stealing it...
Perhaps someone is stealing small quantities of fuel, not for its financial
value but as a prank. Install a locking fuel filler cap.


Gasohol...
- You may have switched from one filling station to another,
and not realized that you were also switching from gasoline to gasohol.
- You may live in one of those regions which is required to sell oxygenated
fuel during the cold weather season.

Now that MTBE is in disfavor, gasohol is the most common oxygenated fuel.
Alcohol has a lower energy density than gasoline.

 

How to test if transmission never goes into 4th gear?
Does light white smoke from tail pipe a normal thing?
All of the things happened after I had a lot of problems starting up the car, so i took it to Nissan dealer to service and he said a soleroid which regulates injection of gas to injectors was bad and he replaced it, after it all of the problems started with gas consuption. All of my friends maxima 3rd and 4th generations average 180-200 miles on tank in NYC, while mine is 130-135 miles.
I drive like a normally, do not race or heavy on gas pedal. Do not drive on hwy, just 100% time of city where a lot of stop and go. I always fill up from Amoco gas station with 93 octane fuel. How do you know if it is gasohol or a gas?

Here is a question:
- fuel injectors are sticking open
- "tired" Oxygen Sensors
- bad fuel pressure regulator
- obstructed fuel return line
- bad Engine Coolant Temperature Sensor
- stuck-open thermostat (engine never goes into closed-loop mode)

How to perform a test on all of those symptoms? Estimate cost of replacement?

Thanks in advance!

 

Perhaps there is nothing wrong with your engine. If your fuel gauge is inaccurate, it may read EMPTY when the tank is still half-full. You believe the gauge, refill the tank, and notice that you got only 135 miles since the preceding fill-up. Please measure miles per gallon for an accurate fuel consumption figure.

 

I just did a math! every time i fill up car its $25 for full tank, cost of gallon of gas is $1.89, means I get 13 gallons per fill.

Now divide 135 miles on 13 gallons and it shows 10 miles per gallon.

I read everyone saying 18-19 miles per gallon in city driving.

This pattern has been same for 2 months now.

Any inputs?

 

Method 1) Start from zero and accelerate to a steady 60mph. You should be able to feel each shift. There will be three gear changes plus a gentle change when the torque converter locks up.

Method 2) Drive at a steady 60mph. Press the O/D OFF button. This forces the transmission into 3rd gear. If you don't feel an immediate gear change and also notice the RPMs increasing, then your transmission was already in 3rd gear, though it should have been in 4th.

White smoke is normal for a few minutes after starting a cold engine. White smoke all the time is not normal. Is your engine losing coolant? If so, where is that coolant going? White smoke could be a sign of coolant getting into the combustion chamber and exiting in the form of steam, out the tailpipe.

Please be specific. What solenoid was replaced? It should be printed on the Work Order.

Don't tell me anything more about miles per tank. I will not answer these questions. Miles per gallon is a meaningful statistic. Miles per tank is BS.

If the pump dispenses gasohol there is a printed notice on the pump which says so.

The time has come for you to make a sincere effort to educate yourself. Buy a Chilton or Haynes repair manual and read it. The answers to all these questions is in the book.