A delivery system used on internal combustion engines to deliver fuel for the combustion process. Fuel systems may be comprised of multiple components such as a carburetor, throttle body, fuel injector, intake manifold, fuel pump, fuel lines, high pressure fuel lines, fuel tank, gauges, various ...

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12
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6answers
2k views

Why or why not increase engine efficiency by running the car “fuel-lean” (using a turbo or supercharger)?

Everyone wants their cars to use less fuel, right? I read the following passage about running the car fuel lean from this website: Run the engine fuel-lean, that is, use excess air. It is well ...
5
votes
1answer
152 views

Alternative fuel consumption metric to MPG to measure actual engine efficiency?

MPG is all very well and good, considering that most people that are concerned about their fuel consumption tend to want to get as many miles as they can out of it before they need to fill up again. ...
5
votes
1answer
51 views

2008 Toyota Corolla 141 Fuel Consumption Too High

I recently got a Toyota Corolla 141. The petrol consumption is too bad. It does only around 7.5-8 Km/l. Could you please let me know the reason behind this ? I was told that the vehicle is too heavy ...
9
votes
3answers
131 views

What makes two-stroke engines less fuel-efficient than four-strokes?

It is a commonly-held belief that two-stroke engines are less fuel-efficient than four-stroke engines, and some example BSFC figures appear to confirm this as well. But what is it that causes ...
4
votes
1answer
29 views

Calculating AFR using injector flow rate and mass air flow

Is injector flow rate = Mass fuel flow? If so then AFR = MAF/Injector flow rate. Can someone please confirm this?
6
votes
1answer
25 views

1967 Ford F100 miles per gallon

I plan on getting an 1967 ford f100 and saw that the gas mileage isn't the best on these trucks. The certain truck I have my eye on has a V8 5.8L engine and was wondering if more liters in the engine ...
5
votes
0answers
511 views

What causes more gas consumption - Idling with AC or Heat? [duplicate]

So I have begun doing some research on the effects of idling. So my question is, does idling with the AC or heater on affect how much gas is given off? If possible, please give the percent of extra ...
5
votes
1answer
33 views

Fuel system question

See red arrow in the image. I place fuel additive in my car, all of the additives went into that pipe (in the red arrow image) because i didnt know how to place it. Will it still work? or just a ...
5
votes
1answer
36 views

Why does my 2005 Mitsubishi Pajero use excessive amounts of fuel?

I have a Wagon with excessive fuel consumption. It's using 30 litres of petrol per 100 ks. I have seen many mechanics who can't find the problem. I know it has good intake and no exhaust problems. ...
1
vote
0answers
28 views

fuel consumption in CR-V 2007

lately I found my car consuming more fuel than usual,it was doing 8 liters per 100km,then it raised to 12 liters per 100km,I asked its agency to check for the problem,they found nothing unusual,after ...
6
votes
4answers
191 views

Cheap vs Expensive Fuels [closed]

What is the difference between the cheapest fuels in a place like Tesco's and the 'high quality', highly priced competitors? Is there actually any noticeable difference in available power, engine ...
6
votes
1answer
45 views

Gasoline grade manufacturer recommends vs what was used during testing

Toyota recommends to use regular(87) grade of gasoline, but tested cars with the gasoline grade 91(see user manual). Somebody know why they recommend to use grade 87 if they did not tested cars with ...
5
votes
2answers
56 views

What senses/controls how much fuel is spent for a given RPM?

When maintaining a constant speed on the highway whether up, down or flat the engine still has the same RPM (assuming the incline is shallow enough not to require a gear change) - common sense would ...
6
votes
1answer
151 views

Why vehicles use fuel and how can fuel economy be improved?

Why vehicles use fuel? Where does the energy in the fuel go? Vehicle fuel efficiency is continuously increasing. Why is this the case? What technologies car manufacturers are using to improve fuel ...
6
votes
3answers
89 views

Will an old engine have worse fuel efficiency than a new engine?

I have a gasoline-engine car that is four and half years old and has been driven for 60 000 kilometers. I have noticed that the fuel efficiency is not what it was when the car was new. However, I ...
1
vote
2answers
96 views

Fuel Consumption Paradox

I've been trying different driving styles for a while now, in an effort to reduce my fuel economy and tank range. I've found that I get the best results when racing around, as opposed to driving ...
2
votes
1answer
44 views

Fuel consumption is bad

I currently own a 2010 Honda Civic 1.8L and a 2012 Honda Jazz(Philippines) / Fit (USA and Japan) 1.5L. I just purchased a second hand Jazz/Fit about 2 weeks ago and the mileage is 32xxx. Btw we use ...
5
votes
2answers
312 views

Is manual start/stop good on older cars?

I have an old car (but with electronic injection) that predates by far start/stop systems which are used nowadays to save fuel (turning off the engine brings savings after 3-5 seconds, see Calculating ...
4
votes
1answer
76 views

2014 Nissan Pathfinder decreasing fuel economy

I purchased a slightly-used 2014 Nissan Pathfinder in January 2015 and have been using it to commute to work (almost exclusively, with the exception of the occasional trip). It currently has 41,000 ...
3
votes
2answers
53 views

1980 Chrysler LeBaron Failed Emissions Test

My 1980 Chrysler LeBaron (V8 318ci) just failed an emissions test. I'm coming from a state without emissions testing to a state that requires it. Specifically, the only part that failed was the ...
7
votes
5answers
267 views

Fuel consumption at same speed of different engine

I am wondering why two car running at 100 km/h for example with a 100 hp consume less fuel that an engine of 300hp. Even if I take a supercar lighter and more aerodynamics it will consume more. But ...
4
votes
2answers
53 views

Fuel Economy Gauge Modification

I have a little digital screen in my dash that re-evaluates my average fuel consumption (L/100km) every thirty seconds. How can I modify this to increase the reporting frequency? Preferably, at least ...
4
votes
3answers
84 views

How would a bad barometric reading affect gas mileage?

My wife drives an '08 Hyundai Azera Limited 3.8L with ~79k miles. Over the past few months she has been complaining that the gas mileage has gone down. Normal around town driving was getting us ~19.6 ...
2
votes
2answers
62 views

Fuel gauge not accurate

This does not always happen but it has happened twice in last 6 months. My fuel gage is accurate most of the times but these two times it was showing that there is 10-15% gas in my tank but my car ...
1
vote
3answers
310 views

How to calculate fuel consumption?

If i know the rpm at which the (tachometer indicated) engine is running and the current speed and the engine capacity is there a where to calculate the fuel consumption of the engine? Need not be a ...
3
votes
2answers
221 views

Does Max Power RPM Equal Max FE?

I was looking over the specs for a 98 Mazda 626 2L and noticed that it says the max power is at 5500 RPM. Will the Max Power RPM also be the RPM at which the engine is most efficient assuming ...
3
votes
0answers
31 views

Integrating Fast OBD Readings and GPS

I'm working on a project to look at fuel consumption on different roads and I need the OBD reader to log the GPS coordinates every time it takes a reading. I'm looking at instantaneous fuel ...
2
votes
2answers
678 views

For 2 identical car models, 1 being cabriolet, which consumes less fuel?

What is the effect on car fuel consumption of having a roof or not? I guess it may depend on the car model, but generally, considering common commercial cars, which setting saves more fuel?
2
votes
2answers
312 views

Mileage varies by driving at different speeds

I drive my car a lot. I do lot of experiments with speeds while driving. Following are my observations: Driving at 60 - 70 km/h gives maximum mileage Driving at 70 - 90 km/h gives good mileage ...
3
votes
2answers
182 views

Why does my front wheel rotor is heating up more than rear one?

I had been facing high fuel consumption lately. To my surprise I discovered that my front wheel free rotation seems bit restrictive to my rear one even when rear wheel drags chain and two sprockets ...
2
votes
1answer
45 views

Are CO2 emissions proportional to MPG figures?

I was looking at the car tax (VED) system in the UK, as I'm considering buying a new car. I was just wondering, are CO2 emissions always proportional to the MPG figure of a car, both in theory - ...
2
votes
1answer
96 views

Which convenience features in a car affects fuel economy?

I understand that the A/C compressor runs with the engine belt, so it will always uses some HP when engaged, therefore it will have some effect on fuel consumption. What I want to know if there are ...
6
votes
2answers
142 views

How to find the cause of sudden high fuel consumption of a motorbike?

About my bike Model: Honda CBR 250R Total Run: 35000kms Total Time: 2 years 3 months Clutch Plate changed at 30k kms after an accident Engine oil, engine oil filter and air filter changed in ...
4
votes
1answer
156 views

Fuel efficiency and volumetric efficiency

I was reading about the better volumetric efficiency of DOHC engines as compared to SOHC engine and was wondering if fuel efficiency is directly related to volumetric efficiency.
4
votes
2answers
443 views

How much fuel does it take to start an engine?

I appreciate this is a question that can't be answered in facts and figures, so I'm after a general idea. I drive a 1986 Supra, which has a modest 2.8-litre engine. I often shut the engine off while ...
4
votes
2answers
215 views

Loss of engine power between 2100 and 2500 RPM on humid days - 2011 Malibu

I drive a 2011 Chevy Malibu LT (4 cyl, 2.4L, 6 spd. automatic) and have been experiencing this problem for the past year and a half. Basically, whenver its hot (90f+) and humid out, my car exhibits ...
7
votes
3answers
422 views

Calculating MPG from MAP sensor (or converting MAP data to MAF data)

My 2002 Honda Accord V6 has a Manifold Absolute Pressure sensor (MAP). I understand that this sensor gives out information in pressure units (psi or equivalent). After doing a bit of research, I ...
8
votes
8answers
1k views

Is shifting to neutral on a decline more fuel efficient than keeping the gear engaged?

I always had the habit of shifting to neutral on long declines and using the brakes to slow down as needed. Intuition made me believe I'd be saving fuel as opposed to keeping a gear engaged. However, ...
2
votes
1answer
447 views

What is Total litres (reserve, usable)15 litres (3.2 litres reserve, 2 litres usable)?

I bought a new bike(Pulsar 150), and while reading its specs in the user manual i found Total litres (reserve, usable) = 15 litres (3.2 litres reserve, 2 litres usable). what does this mean, I assume ...
6
votes
1answer
301 views

Oily Sludge in the Intake Manifold

When taking off the throttle body to clean my IAC, I noticed that there was a thick layer of oily sludge coating pretty much everything inside the intake manifold: I have two queastions: How did ...
2
votes
2answers
483 views

fuel consumption

What is the normal fuel consumption for injection type Toyota carina e 1.6 cc 4A engine? My 1995 Toyota Carina e car gives 9.5km/l in city and 12 km/l on highways. How can I increase it more? toyota ...
12
votes
1answer
8k views

How much does spark plug gap affect fuel efficiency?

I've read conflicting reports regarding how plug gap can affect fuel efficiency. For example, I've read that too small a gap won't cause a clean burn, or that too large a gap can cause misfires due ...
4
votes
1answer
55 views

How is “Fuel consumption (economy) - combined” Calculated?

I have a Mazda - 323 S V (BA) - 1.8 i 16V (114 Hp) and the data sheet for it says: Fuel consumption (economy) - combined 7.9 l/100 km. How is this calculated and under what driving conditions?
10
votes
2answers
2k views

How does ambient temperature affect engine efficiency and fuel consumption?

I remember from my physics class that the ideal-gas Carnot engine is more efficient if the temperature difference between the heat source and the thermostat ("heat recipient") is larger ...
2
votes
1answer
380 views

Changed O2 Sensor and my mileage went down

I changed the O2 sensor on my 97 Mazda 323 BA 1.8L BP DOCH Lantis and my mileage actually went down. The car had the original sensor in it, with about 200,000 kilometers on it and I replaced it with ...
-1
votes
2answers
1k views

Why are American cars less efficient compared to european European/Japan cars [closed]

A normal average European car has a engine with less than a 2.0 liter engine which consumes 1 litre of fuel in 18-22 km. A normal average American car has a engine at least a 2.5 liter engine and ...
4
votes
2answers
751 views

How much improvement from replacing an O2 sensor?

I'm currently getting about 19.6 mpg city in my 97 Mazda Lantis 323 / Protege 1.8L. According to fuelly a car like this should be getting around 26 mpg. The car has about 127k miles on it, and I ...
11
votes
8answers
33k views

What can cause a car to consume more fuel?

All over my long driver career, I had 4 cars (5 years). I always compare my fuel consumption with other people who have the same car. 3 times out of 4, I found out that my cars were consuming more ...
10
votes
13answers
59k views

Is the ECON button just a placebo?

I recently bought a Honda Civic that had this in the car: I have no idea what it does, and how it's supposed to help. Even Honda's website is ambiguous, just using a lot of fuzzy words to describe ...
2
votes
1answer
226 views

Automatic Throttle Body and TPS on a Manual

This is in continuation to my question Fast Idle and High Fuel Consumption. I just bought a Manual 97 Mazda Lantis 323 1.8L DOHC 16 Valve BP ( apparently called a Protege in the US ) which has a fast ...