New answers tagged

0

Fuel, Air and spark in the right amounts and at the right times are what makes an engine purr. In your car there is an engine computer that controls these things (unless you are talking pre 1983 or so...) Generally problems involving fuel will set an OnBoard Diagnostics (OBD) code. Air issues are not all that common, and generally come from a totally ...


3

Those are the remnants of gasoline When you let gasoline evaporate it leaves behind various elements within the gas that can't dissipate through evaporation. These remnants can clog various galley's in your carburetor as well as clog jets. Even if you are soaking your carburetor you will still want to physically clean out the jets and use compressed air ...


7

Gasoline is a pretty toxic liquid. And it evaporates pretty easily. The Carbon Cannister is a system to help keep toxic fumes from gasoline out of the environment. So here's how it works. You fill your car up with gasoline at the gas station. You add a gas cap to seal off the tank. Cool, no evil fumes can evaporate from your gas tank and contaminate ...


-1

I use 94 octane ethanol free fuel. It supposedly has a shelf life of 2 years. Not going to test that though!


2

Surely there is a far simpler answer to this. Fuel in injected on the "suck" stroke, when the piston crown is traveling down the bore, thus effectively creating negative pressure in the combustion chamber. There is therefore no pressure to be pushed back into the injector. Yes the fuel is at a serious pressure, yes the injector is effectively a one-way ...


8

In cylinder pressure is in the 200 psi range. GDI fuel pressure is varied from 500 up to around 3000 psi. This alone is enough to keep fuel blow-back to a minimum. Carefully engineered injector pintle shape also helps. This is no different than port injectors. What is unusual is how the pintle is moved in a GDI injector. In the most successful designs the ...


8

I will try to answer this as best as possible. There are a few factors that come into play here (Mainly the manufacturer of said engine). Direct injection petrol engines work much like a diesel. You have a low pressure fuel pump that resides in the fuel tank itself, and a super high pressure pump that sits near the fuel rail that delivers fuel to the ...


3

Best to check the intake valve seals. If the shim is too large it won't allow the valve to seat properly, allowing pressure to be pushed back into the carb.


1

You could use a float from a motorcycle You can get these used from various motorcycles for very cheap. From there you can use a propane torch to unweld them from their hangar and braze them onto your float arm. The fuel will never degrade one and there are plenty of them around for a very low cost.


1

I've successfully used ping-pong balls in the past, on gasoline and diesel vehicles.


1

Cork will be porous so probably not a wise choice. If you have a rare car and can't find an appropriate scrap vehicle (which would be my first choice) then a ping pong ball firmly secured to the sender are will be very effective.


0

You probably allready thought of this but have you concidered getting one from a scrapped car? i use parts from the car dump all the time and i rarely have issues. Sometimes you might even get it for free concidering the guys working at the scrapyard are usually nice guys :)


2

Dirt in the tank could definitely be the cause of the burned pin because the burned pin suggests that the pump was drawing a larger than normal current from that wire. The pump having to contend with dirt in the tank could mean it was having to work significantly harder than when pumping clean fuel which would be a very good reason for it to draw excessive ...


1

i have a 2007 hyundai accent that is having the same problem and it would stall all the time and i had to let it sit for a while before it would start. i ask around and a friend told me to check the map sensor. so i got a new one and put it in and had no more problems with the car stalling. so check that and see if that helps


1

The 97 Mercury Tracer doesn't use a Fuel Rail Pressure sensor and any reading you're getting from your OBD2 application is false. If you believe that the fuel pressure is low, hook up a fuel pressure gauge and verify before replacing anything. Refer to Brian Knoblauch's answer for potential causes.


6

Voltage drop the ground side pin 4 with the car running. I'd suspect a poor ground is the cause. You can also scope the power side by removing the fuse and putting a wire loop in place. Connect a low amp probe. Since the fuse is rated @ 20A you should expect to see 8-10A if it's drawing more amps than that suspect a short to ground or a bad ground or ...


1

What you are seeing is the use of fit type to form a positive seal. Older vehicles used harder materials (not to be mistaken for toughness or strength) for most parts. As a result it was possible to use an interference fit or a transition fit to form a seal. Attached is an image explaining this. Essentially, the fit is literally to tight for any fluid to ...


1

The clatter usually associated with diesel motors is a result of the much higher forces of combustion in a diesel motor which at or about TDC (top dead center) "slaps" the moving assembly. Some of the newer motors are much quieter by virtue of having a pilot injection as well as (in the case of piezo injectors) up to 7 injection events per combustion cycle.


6

Yes, running low on fuel can damage your fuel pump, but as IHaveNoIdeaWhatImDoing mentioned in the comments below, modern fuel tanks are sophisticated enough to prevent fuel pump starvation until the tank is almost complete empty. Either way, damage to the pump can occur because fuel acts as a coolant for the electric motor. When there is no more fuel the ...


4

It is because the fuel lubricates and cools the pump. If you leave the tank run dry, the fuel pump will turn dry, which will overheat it and may cause the electric motor to fail or otherwise to reduce its service life. The same principle applies to the water pump when it is electrically driven, like in the Toyota Prius. When burping those kind of systems, ...


10

Carburetor Circuits Will Still Pull Fuel from the System If the engine is running on a carbureted vehicle, off throttle or not, it will consume fuel. Throttle Settings There are three basic circuits in a most carburetors that provide fuel to the ICE. Idle Circuit - effects fuel metering at low RPM conditions where the throttle plate is closed. Secondary ...


14

At a base level, carburetors meter the amount of fuel they let into the engine by the amount of air that is moving through them. Vacuum is created by the piston moving in the engine and creating an open space. As the piston moves down, it creates an empty volume which pulls in air through the only opening it can find, which is the passageway through the ...


15

Carburettors are very crude in comparison to EFI systems, and so the amount of fuel entering the engine is simply a factor of the amount of air going in, which is controlled by the position of the butterfly (and hence by the throttle position). At a completely closed throttle, there will therefore still be some fuel getting in, enough to keep the engine ...


9

The gas gauge measures the level in the tank by a float lever, not by pressure. So this doesn't affect your gas gauge. The overpressure in your tank is completely normal. Gas has a relatively high vapor pressure, which means it tends to vaporize easily and even builds up a pressure when enclosed in a tank. Modern cars have to avoid the emission of fuel ...


4

The first part of your question has already been asked here - Why is there a hissing noise when I open my petrol cap? It is normal for a fuel tank to do this. This will not cause your fuel gauge to show full all the time. Your fuel level sensor is probably faulty.


2

Kind of a long shot, but I had this problem with an old Nova, turning right. That was due to loose screws in the carb. It might have been the mounts to the intake manifold; but, my vague memory is of tightening screws on the topside. It was a long time ago.


4

My theory is you have a stuck float in your carburetor. This is causing the fuel bowl not to fill completely. When you go around the corner, the main jets are without fuel (sucking air) and this kills engine power. Getting the carb rebuilt (or at least looked at) will probably solve the issue. You may also try using a plastic handled screwdriver and using ...


4

The gas gauge is just an indicator and each vehicle is going to be different. I know the older Datsun Z cars had two gas gauges, one was the main one which showed the volume of gas down to 1/4 tank, while the secondary one showed from 1/4 down to empty. The secondary gas gauge was very accurate to give the driver a true indication of how much fuel was in the ...


-4

This is a really easy question. A vehicle coasting down a hill with with a manual transmission in neutral with the clutch press and held to the floor will burn less fuel than coasting in any gear. WHY: because an automatic transmission in neutral has a lag on the engine. The Manual transmission in neutral with the clutch press does not have a lag on the ...


4

TL;DR: On my experience - Long hills on gear, short slopes in the city - on the neutral (not breaking the limits of speed and sanity). On my petrol powered '97 MMC Galant i've got a custom made trip computer for counting fuel consumption, that is hooked up directly to the fuel injector wires. Here's my observations: when coasting downhill at 4-th gear (i've ...


9

As Steve Matthews noted, modern cars will not use fuel while coasting downhill in gear. This is called Deceleration Fuel Cut-Off and uses various sensors to determine the engine load (i.e. the car is driving the engine) and whether the throttle is at idle (i.e. the driver's foot is off the pedal). The engine computer will then stop injecting fuel. Generally ...


5

Technically speaking, coasting in neutral may save you some gas, because mechanical losses in the engine at ~3000RPM are greater than the power needed it run it idle at ~500RPM. Coasting in gear won't consume any gas, but it will slow you down faster, requiring you to reaccelerate earlier than you'd have to when coasting in neutral. However, if you're in ...


9

If you're looking at just the fuel consumption whilst going downhill, then yes, as Steve Matthews said you'll use less fuel if you're in gear and foot off the throttle - likely no fuel at all. But you also need to consider after the hill - if you don't brake and allow the car to freely accelerate down the hill, you'll then have considerably more speed than ...


35

If the car is equipped with a modern fuel injection system, it will likely use less if left in gear and allowed to run against the transmission with no throttle as modern fuel injection systems can and do shut down the injectors completely thus use no fuel whatsoever. If the engine is at idle in neutral, the ECU will have to use a small amount of fuel to ...



Top 50 recent answers are included