Fuel system covers the components of a car responsible for fuel delivery; tanks, pumps, filters, pipes. Questions on carburettors and injection systems have individual tags

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63
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9answers
26k views

What are the benefits of premium (high octane) petrol?

Here in the UK it's common for petrol (gas) stations to offer both regular and "premium" unleaded petrol. The premium stuff is (naturally) more expensive, and I've often wondered what the actual ...
15
votes
4answers
56k views

Symptoms of Lean or Rich carb settings on a motorcycle

I have a 1981 Yamaha XS650. I recently put in K&N stock replacement filter (ie, they are in the airbox and conform to the size of the original), however they may be leading to a leaner mixture ...
13
votes
1answer
4k views

how to optimize fuel consumption by changing the rear differential ratio?

Is it possible to improve the fuel consumption (decrease it) in my van by changing the rear differential ratio? I would like to optimize it for low-speed driving about 40 km/h (25 mph). Is it true ...
23
votes
8answers
63k views

Will higher octane fuel improve gas mileage?

I've heard from some people that high octane fuel will increase gas mileage. Around here, we have the basic unleaded(87), mid-grade(89), and premium(93 or 91). I've been using the basic 87 unleaded ...
41
votes
5answers
112k views

How long does it take for gas to go bad?

Approximately how long does it take for unleaded gasoline in the tank and fuel lines to become unusable in a car that is not being used? What causes this, and what can be done to prevent or remedy ...
17
votes
1answer
533 views

LTFT and STFT values are off and don't make sense

Car is a 2015 BMW M5 and it has an aftermarket CAI and a catback (slip on) exhaust. No other performance mods or tunes. About 6-7 months ago, I bought a Kiwi OBD-II reader, simply out of curiosity ...
62
votes
9answers
41k views

Does the amount of fuel in the tank matter?

As long as there is some fuel in the tank, does the fuel level matter? In other words, is it advisable to make sure the tank is mostly full most of the time, or is this just silly? In other words, are ...
13
votes
6answers
13k views

How to improve fuel economy in high-mileage car?

I'm driving an 2003 Acura TL 3.2 with 177K miles on it. I bought the car with 110K miles on it. It seems to me that the car is not getting the same fuel economy that it did when I acquired it. I ...
4
votes
8answers
16k views

When given a choice between octane 89 and 93, which should I choose?

I just recently got a 2005 Volvo S40 with a turbo engine; I want to take good care of it, so naturally, when the instruction manual recommends 91 octane fuel but says it takes a minimum of 87, I have ...
12
votes
2answers
158 views

Motorcycle Four Body Carburetor Synchronization Balancing

I would like to adjust four-body carbs by myself, in order to avoid spent money every time. What are the basic rules, tools and secrets of synchronizing multiple carburetor bodies?
6
votes
3answers
29k views

Are fuel system cleaners (like Gumout) worth using regularly?

Are fuel system cleaners (like Gumout) worth using regularly?
12
votes
4answers
5k views

Difference between high octane and low octane?

What is the difference between high octane and low octane fuel? I'm not asking if one is better than the other for my vehicle, specifically, but rather what occurs differently both scientifically and ...
7
votes
3answers
3k views

Cleaning fuel injectors?

I took my car (2006 Honda Civic) to firestone to get an oil change and they told me I should get the fuel injectors cleaned. I was in an Advanced Discount Auto Parts store the other day and I noticed ...
2
votes
0answers
2k views

Fuel Consumption and other Fuel related data from basic OBD-II parameters [duplicate]

I want to know how can i obtain the values of Fuel Consumption, Fuel Economy and other fuel related information from basic OBD-II parameters like Vehicle Speed, RPM, TPS etc. I have noticed that not ...
10
votes
6answers
10k views

Why does a diesel sound like that?

My car is in the shop for a repair, and they gave me a loaner. It's a Chevy Cruze Diesel. Sitting on the driveway, my wife said, "It sounds like a truck". It does. So what exactly it is about ...
6
votes
0answers
60 views

1993 Merc 300SE always stalling soon after startup, fuel pressure tests > 50psi

From the moment car starts to the moment engine stalls, which is about 40 - 60 seconds, fuel pressure is always above 50 psi. Can I safely conclude stalling is not caused by fuel system problems? I ...
6
votes
4answers
2k views

Does the tachometer provide any indication of fuel usage?

So, I'm driving along on the highway with the A/C blasting when I notice the price of gas. It makes me think, "what can I do to increase my fuel efficiency?" Some of the tips I've heard have included ...
4
votes
3answers
33k views

What would cause a car to lose power a few seconds after starting, then run normally?

I start my 2003 Honda Civic each morning and drive to work. A few hundred feet down the road, the engine will sometimes behave as though it is running out of gas and lose power momentarily. It ...
17
votes
5answers
49k views

Why should the fuel petcock valve be turned to “Off” position when not using the vehicle?

It’s mentioned in the user manual of my motorbike, that when not using the vehicle, I should turn the petrol tap (the one that has three positions “On”, “Off” and “Reserve”) to “Off” position. I don’t ...
8
votes
3answers
22k views

Can I use lower octane fuel at high elevation?

Here in Colorado, gas stations sell "regular" gasoline which is rated at 85 octane ((M+R)/2). In most of the rest of the US, 87 octane is the lowest grade available. (As noted previously, higher ...
8
votes
5answers
13k views

Doing my own fuel induction service - how to, and how difficult?

I was recommended to get a fuel induction service for a 2002 V4 Camry, and am considering doing it MYSELF. The reasons for considering this are: My car idles a bit rough, especially when the AC is ...
4
votes
2answers
160 views

Intermittent stall at idle

I have a 98 Saturn sw2 with a recent problem. Two times now it has stalled while idling and when it doesn't stall it floats near 500 rpms (Usually 750 - 950). The first time, it would start and just ...
2
votes
3answers
5k views

Slow acceleration, high fuel consumption after spark plug change

I have a 2000 Ford Ranger 4.0 L V6 4x4 model. I recently was having some problems with the truck idling too low when cold and I decided to change the spark plugs. I put in 4 out of the 6 new plugs and ...
10
votes
3answers
18k views

How do I safely siphon gas from a tank?

Our 2003 Windstar was recently totaled in an accident (everybody's ok). This happened the day after we filled the tank. Before we hand over the car to the insurance, we'd like to get the fuel out of ...
9
votes
3answers
1k views

What are the causes of fluctuating intake manifold vacuum

I have a 2005 Honda CBR600 F4i which suffers from occasional hesitation at low rpm when accelerating. I also get occasional fault codes from the ECU indicating a vacuum leak. Today I connected a ...
7
votes
1answer
58 views

Vespa PX 150 Fuel and Carbon issue

I am using Vespa PX 150.It is using Contact Point system. The issue is it is consuming fuel more than average and the plug is full of carbon after approx 50 Km.The engine not start unless I clean the ...
7
votes
2answers
304 views

What are all the different types of fluid in a car and a short summary of their use?

A fluid is defined as anything that flows, hence for our purposes a gas or a liquid. I know that there is fuel, engine oil, engine coolant and brake fluid. Also air is normally taken in through a ...
7
votes
1answer
546 views

Why is there a hissing noise when I open my petrol cap?

When I fill up with fuel, there is often a loud hissing noise, as if you are opening a bottle of fizzy drink or something whenever I unscrew the petrol cap. It also seems like there are vapours ...
5
votes
1answer
5k views

What is seafoam? What does it do? How do you use it?

Mech's seem to get a real rubbery one about Seafoam. Is it just fuel additive, like something similar to Lucas Oil? Do I just pour it into my gas tank as a gas treatment? What will it do/help ...
5
votes
3answers
4k views

Car stalls when braking (VW Mk1 Golf)

I have bought a Mk1 Cabriolet that has been sitting for over a year. I am trying to get it road worthy. So far so good, but I am having an issue with the engine and braking: The engine stalls when I ...
5
votes
2answers
620 views

Does the a gasoline or diesel engine supply fuel at high speeds when not pressing the pedal and more

Let say I directly connect a small engine to my bicycle, and that I'm superman who can overcome any force. Then I start cycling (using my legs...) - the engine starts to rotate, even though I haven't ...
5
votes
2answers
2k views

How to know how much fuel is left when the light turns on

In general, where can one find information about the quantity of fuel that is left in the vehicle's tank when the warning light turns on? More specifically, in a Suzuki Swift GLX (auto) 2010 model?
2
votes
3answers
594 views

Is Petrol usage Proportional to Gas Pedal position

I was wondering about this the other day. Is the petrol usage in the car only influenced by the position of the gas pedal? So for example if I take my foot of the gas and coast for 30 seconds, would ...
2
votes
1answer
479 views

Kawasaki ZZR600 Model D3 - where is the fuel filter?

I've been looking for the location of the fuel filter. At first I thought it might not have one, and only the Model E ZZR's have one, because there seems to be no explicit mention of it or diagram in ...
2
votes
1answer
617 views

Can I use ethanol instead of petrol in my car?

I have a 2001 Ford Focus (EU/UK spec) and I'm planning a road trip to Europe. My research shows that they serve up something called E85 at their petrol pumps in addition to petrol and diesel. I've ...