About gasoline, diesel and other fuels.

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46
votes
8answers
10k 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 ...
42
votes
9answers
6k 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 ...
34
votes
7answers
3k views

What to check when buying a used car?

I'm looking to buy a used car. What do you think I should check (mechanically) before buying it (especially if it's diesel)?
33
votes
5answers
33k 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 ...
19
votes
8answers
27k 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 ...
10
votes
6answers
7k 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 ...
9
votes
7answers
8k 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 ...
9
votes
5answers
5k 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 ...
9
votes
3answers
7k 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
1answer
2k 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 ...
8
votes
5answers
4k views

Is it normal for the oil to be dark in color right after an “oil change” in a 10-year old diesel car?

I took my 2002 Jetta TDI wagon to a neighborhood shop about 10 miles, 24 hours ago. They supposedly changed the oil, but the color is very dark, almost black. Definitely not light-colored/transparent. ...
8
votes
2answers
16k views

How to test for defective glow plugs?

On a diesel engine, how can I know which glow plugs are defective, and can I change these only?
7
votes
3answers
2k 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
1answer
548 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 ...
6
votes
2answers
11k 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 ...
6
votes
4answers
1k 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 ...
6
votes
3answers
3k 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 ...
6
votes
2answers
3k views

Why do head gaskets fail in diesel engines?

I'm considering the purchase of a 2001 VW Golf TDI "mechanic's special", so named because it apparently has a failed head gasket (white smoke). I'm not a mechanic but I'm fairly handy with tools and ...
6
votes
3answers
17k views

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

Are fuel system cleaners (like Gumout) worth using regularly?
6
votes
2answers
3k 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 ...
6
votes
1answer
200 views

Re-programming injection pump on French Ford Focus TDCi

I replaced the engine on my 2003 Ford Focus (French TDCi) and I plugged it to clear the error codes. Now it starts ok but stops after 10 minutes. I read that when a new injection pump is installed, ...
6
votes
2answers
999 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 ...
6
votes
1answer
633 views

BMW 530xd e60 2008 diesel engine turns but won't start

I have a problem with my BMW, just bought it, previous owner hasn't been facing such problems. When the engine is cold for e.g.: after night. Outside temperature is about -4 to +1 degree, engine won't ...
5
votes
2answers
1k 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?
5
votes
4answers
780 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 ...
5
votes
5answers
15k views

Racing Fuel (100 Octane Rating) - Better than Premium?

Earlier today while driving out East on Long Island I stopped to fill my tank with gas, and at the station, all the pumps had the usual Regular, Mid, Premium on one pump, but on the 2nd pump which ...
5
votes
4answers
228 views

Is it even possible to buy gasoline anymore that does not contain ethanol in the US?

I can't remember the last time I went to a gas station and it didn't have a notice that the gas contained some quantity of ethanol. As I understand it, ethanol is harder on my engine than regular ...
5
votes
1answer
2k 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 ...
5
votes
3answers
139 views

I'm looking to buy a new car and I'm wondering what does more damage on a car: time or miles?

So the title is pretty self explanatory. I'm looking at getting a minivan, and there is a 2011 model with 50k miles, and a 2008 model with like 30k miles. What's better? Is it better to have ...
5
votes
2answers
235 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 ...
5
votes
6answers
2k views

what can be the reason my old diesel Mercedes won't start?

The vehicle is a Mercedes-Benz T1 model 308D. The engine is an old Mercedes-Benz OM601.940 4-cylinder indirect injection 58 kW (79 hp) 2299 dm3 diesel engine from year 1992. It's not a turbodiesel! - ...
5
votes
2answers
1k 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 ...
5
votes
2answers
416 views

What does this device on a 1985 Mercury Lynx/Ford Export Diesel do?

I have a 1985 Mercury Lynx (Ford Escort) Diesel 4 cylinder. The device shown in the pictures -- below the starter -- has a hose connecting it to the radiator. There is another hose that is ...
5
votes
2answers
307 views

1993 Jeep stalls on acceleration, floods, hard to start

My 1993 Jeep Wrangler has about 200,000 miles, in good shape. It usually starts right up, but it's started intermittently flooding, so that I have to crank and crank with the accelerator all the way ...
5
votes
2answers
138 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
1answer
93 views

'83 Mercedes 300TD will not start when warm

The car runs great when first started, great pickup, etc. However, if I stop and shut off the engine, it will not start back up. At times I can pump the accelerator 5 or 6 times and then it will start ...
5
votes
3answers
113 views

Is the fuel in my engine under pressure?

I have a 2008 Seat Leon FR TDi and need to change one of the fuel pipe (which has become torn slightly). The hose is ~ £50 + VAT so I am keen to do it correctly. Can anyone advise if the fuel in my ...
4
votes
4answers
803 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
999 views

What kind of engine oil to run a Diesel?

I got an 1987 Toyota Land Cruiser with a 2H diesel engine. I never changed oil on a diesel engine prior to this truck, so I'm a little confused. Toyota Factory Shop Manual recommend API CC oil type, ...
4
votes
7answers
5k 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 ...
4
votes
2answers
148 views

Proper fuel for motorcycles?

I've heard that regular petrol (92 octane ULP) from some fuel companies is not good for motorbikes as it is intended for cars only. Is this just an old wives tale?
4
votes
1answer
942 views

Is there a standard for how much fuel is left in the tank when the meter reads empty?

I know this question is very similar, but I am specifically talking about the fuel gauge and not an indicator light. Almost every car I've owned could run for quite a while with the fuel gauge reading ...
4
votes
2answers
561 views

Add 2 stroke oil to a 4 stroke petrol engine during burn-in period

I'm planning to get a new petrol (gasoline) car soon. A friend of mine, who worked as a motorbike mechanic when he was young, told me he puts a small quantity (125 ml / 4 oz) of 2 stroke oil in the ...
4
votes
2answers
3k views

Why does my engine perform poorly and get bad gas mileage after using fuel injector cleaner?

At the advice of someone at a local auto parts shop, I poured a bottle of fuel injector cleaner into my gas tank. This happened around the same time that I had a brake job done and rotated my tires. ...
4
votes
2answers
422 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 ...
4
votes
2answers
119 views

Can I use a CNC machine or waterjet to make an adapter plate to adapt a 5 speed transmission to a rare, obsolete engine?

I am the sad, proud owner of a Nissan SD33T (Diesel), mated to a 4 speed T-19. The power this engine outputs (101HP, 160#/TQ stock) means it struggles on the highway, and I don't want to sacrifice my ...
4
votes
2answers
55 views

Why can't I fill my gas tank in one go?

For the past couple of months, I've been having trouble filling my gas tank. I have a 2003 Hyundai Elantra, which has a 55-liter tank (approximately 14.5 US gallons). When I buy gas, the pump clicks ...
4
votes
1answer
326 views

2008 Ford Mondeo 2.0 TDCI cranks but won´t start

Ok, so I´m having this problem with a 2008 Ford Mondeo mk4 with a 2.0 TDci engine code AZBA, same one Peugeot uses in other cars such as the 407. Car was having trouble a few days back to start ...
4
votes
2answers
3k 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 ...
4
votes
2answers
763 views

2010 Toyota Corolla - pumping gas - the gas pump kicks off constantally

In another forum someone said "Screen down the fillneck may be partialy plugged up with matter." Is this something a neophyte can change or fix himself, or should I take it to an auto shop? How can I ...