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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58
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9answers
24k 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 ...
56
votes
9answers
38k 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 ...
38
votes
5answers
100k 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 ...
21
votes
8answers
60k 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 ...
16
votes
5answers
43k 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 ...
13
votes
6answers
21k views

How to properly dispose of old fuel?

I have some old 2 stroke mixed gas I need to get rid of. This could also apply to old fuel removed from a sitting car or any vehicle for that matter. What is the proper way to dispose of this? Are ...
13
votes
1answer
155 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 ...
12
votes
9answers
11k views

Diesel vs Petrol motorcars. Pro's and cons?

I realize this may be a silly question to those of you on here who are proper petrol-heads and this may even be a repeat question, but I could not find anything on it on here, so here goes: What are ...
12
votes
5answers
516 views

How exactly does running fuel-lean increase the temperature of ignition?

I learned in this question that running an engine fuel-lean will increase the temperature of ignition, among other things such as causing problems with the catalytic converter. I have no idea how or ...
12
votes
1answer
3k 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 ...
11
votes
2answers
6k views

I accidentally fueled my car with E10 (10% ethanol). What should I do next?

So I have a 2000 Honda Civic LX that is around 130k miles now. In Las Vegas, I put E10 (I hadn't known what it was before this...), and had to get it fixed. The engine light had started blinking and ...
11
votes
6answers
12k 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 ...
11
votes
4answers
4k 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 ...
11
votes
3answers
8k views

Is high octane fuel a requirement for high-compression engines?

I own and use a 2005 Chrysler Crossfire SRT-6 as my daily commuter vehicle. I'm not interested in trying to eek out a few extra miles on a tank, I want to keep the vehicle and its engine running as ...
11
votes
4answers
3k views

Gasoline is dripping out of a rubber tube outputting on the bottom of my motorcycle - is this normal, or is it a problem?

What bike? A BMW 650, 1996 model. What's the problem? I noticed a slow, but steady, drip of gasoline from one of two rubber tubes that output to the bottom of the bike. I think the other rubber ...
10
votes
13answers
60k 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 ...
10
votes
3answers
17k 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 ...
10
votes
1answer
94 views

Why do diesel fuel lines have to be bled?

Background I've had a couple of situations with diesels. One in particular where I swapped a Ford F350 Powerstroke 7.8 transmission. When I was done. The truck wouldn't start. It was a painful ...
9
votes
4answers
1k views

How critical is it to match the stock fuel pressure regulator pressure when replacing it?

My fuel pressure regulator needs replacing, however the original part from the manufacturer is outrageously expensive. While looking for less financially painful alternatives I've seen much cheaper ...
9
votes
2answers
90k views

What happens if you put the wrong kind of gas in your car?

I (like most people) just use regular unleaded gas in my car and always have. But once I accidentally put in the premium kind, mixing it with the unleaded that was already there, and I thought for ...
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 ...
9
votes
1answer
195 views

2001 Infiniti QX4 rough idle - leaking fuel damper vacuum port

I have a bit of an involved problem, so I’ll break it down a bit and try to provide as much detail as possible. My main problem: I have a rough idle on my 2001 Infiniti QX4. It’s not extremely ...
8
votes
5answers
8k 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 ...
8
votes
5answers
11k 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 ...
8
votes
1answer
752 views

how can I measure the amount of fuel injected into a diesel engine in real time in a purely mechanic pre-OBD vehicle?

This is a Mercedes-Benz 308D van, year 1992, model 602.316. Pre-OBD, no electronics of any sort, everything is purely mechanical. I would like to retrofit a system which would measure the precise ...
8
votes
2answers
59 views

Ford Expedition Eddie Bauer 4.6 V8 2003 automatic rpm goes high

When driving, sometimes when I want stop the vehicle, I go to press the brakes, but that time engine rpm goes high, keeping brakes pressed hard, after 5 second engine becomes normal. It goes high when ...
8
votes
3answers
20k 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
0answers
80 views

Leaking Fuel Injector Seal

I recently had to remove the fuel injectors and fuel rail to clean out the EGR ports on my Honda Accord. The EGR port was all clogged up with carbon build up. I replaced all the old o-rings, cushion ...
8
votes
0answers
64 views

Sharp whining noise coming from rear of the car

In my Toyota Vitz 2007, I hear a sharp whining noise coming from the rear of the vehicle. This noise does not always happen. When the vehicle is started, the noise is not there. But after driving for ...
7
votes
2answers
462 views

Why is the effect of a bad fuel pump more noticable at higher speeds?

I get that the main effect of a bad fuel pump is that the engine will cut out at higher speeds, and that this is often not easily noticeable until that happens because there are little or no prior ...
7
votes
4answers
2k views

Subsitute for Leaded Gas

I have an old '73 240-Z that I am fixing up in class. Once I get it running, will I need to add something to the gas? I know that old cars ran on leaded fuel, the lead lubricating the parts as it ...
7
votes
3answers
1k views

What is the Fuel Tank Ventilation Valve?

Asking this for a friend. Their mechanic says the fuel tank ventilation valve is broken. What is the fuel tank ventilation valve? What does it do? Is it an important part? If yes, Why? EDIT: In ...
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 ...
7
votes
3answers
805 views

Is it okay to run aviation fuel (100 low-lead) in a dirt bike?

I'm wondering if it will be okay to run 100 octane low-lead aviation fuel in my 2007 RM250 motocross bike (two-stroke). Half of the people I've asked say yes, while the other half say no. Will it be ...
7
votes
1answer
43 views

Suzuki 2004 sv650s wiring

I got a 2004 sv650s Suzuki when I turn the key on the fuel pump does not come on and the CHECK light comes on on the dash. All the lights come on and the starter button does not work.All the fuses are ...
7
votes
2answers
7k views

Test Gasoline for Water Content

I live in a small town, and the Gas station there has a bad reputation for gas quality. With rumors like peoples gas tanks freezing solid and such. Is there a quick, safe, cheap way to test for ...
7
votes
1answer
391 views

Does the air screw only affect the pilot jet?

I have a 2 stroke motorcycle, it's Kawasaki KR150. When I try to do some jetting on its carburetor (it's Keihin PWL26), I saw that there's an air screw. So now I've been wondering about this air ...
7
votes
1answer
29 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
3answers
9k views

What happens when you run out of fuel?

My question is specific to diesel or gasoline (petrol) engines. Many people told me that it is very bad to run out of diesel since it can damage the engine and it's difficult to re-engage it ...
7
votes
2answers
7k views

Power loss in truck - triage options?

I've asked at least one question about my specific situation earlier, but at this point, I'm looking for information on how to operate in triage mode, my primary goal is to get my truck working well ...
7
votes
0answers
41 views

Ford Tractor 5600

This is a older tractor. My question relates to the fuel system. The older fuel injectors don't have any external seals? All of them seat and 3 don't leak but one does. I was looking for a seal but ...
6
votes
3answers
28k views

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

Are fuel system cleaners (like Gumout) worth using regularly?
6
votes
4answers
991 views

How to tune the ECU / fuel trim in a custom-built engine

I have a Gen VI 454 in my Suburban that needs some work. I'm thinking about turning it into a 496 stroker. Once I find a list of mechanical components (crank, cam, pistons, heads... everything) that ...
6
votes
1answer
331 views

Why are V engines less smooth?

I'm learning how to ride a motorcycle on a Suzuki Gladius SFV650, with a V-twin engine. But I also had the chance to ride a Kawasaki ER-5, which has a parallel twin engine (550cc). I've noticed that ...
6
votes
4answers
27k views

Diesel Engine difficult to start

I have a diesel powered Audi A4 B7 (2006) 2.0TDi (the 170BHP variety) with a manual gearbox, which I've owned for around 18 months. The car has just short of 100k miles and has a full dealer service ...
6
votes
2answers
4k views

Car is sluggish, jerking and idles rough.

I have a VW Polo Classic, 1.6L. Just recently it started to be slightly jerky when in idle and whilst driving. There is also a loss of power, a strong fuel smell, and sounding slightly like a VW ...
6
votes
3answers
1k views

Motorcycle with EFI not starting well

I have a 2012 Kawasaki W800. On cold mornings it is difficult to start - it turns over quite a few times before it catches. This is compared to my old carburettor bike which started instantly with the ...
6
votes
1answer
43 views

2000 Celica engine dies or shakes when I pump gas

I have a 2000 Toyota Celica. At first it used to slip gears and then I had a mechanic check it out. He said its a solenoid in the transmission which he changed. The car sputters sometimes when at ...
6
votes
1answer
33 views

2010 dodge ram 1500 reg./E-85

I let my wife put gas in the car and she thought it was E-85. But she put eco-diesel gas (only) 5.00 dollars worth so my guess maybe 2 gallons now my truck smokes a lot and wants to shut off. I bought ...
5
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 ...