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My Car Keeps Cutting Out

P { margin-bottom: 0.25cm; line-height: 120%; } My Car Drives and Then Cuts Out. It Restarts After a Couple Of Minutes
Your car starts and drives okay and then suddenly, it splutters and slows down and then picks up speed again. Or it slows down, splutters and then dies. The fault is erratic: some days the car drives perfectly at all speeds and other times, the symptoms reappear. There's no warning lights on the dashboard. Sound familiar?

It could be caused by a sensor failure, yes, but the symptoms are also classic signs of :
1. A partial vacuum in the fuel tank
2. Blocked fuel filter
3. A failing fuel pump.

Partial Vacuum
Fuel tanks are vented to atmosphere. Air should be able to get into the tank. To achieve this the tank has a small tube which probably appears somewhere underneath the car in the vicinity of one of the rear wheels, or the fuel filler cap itself has a small vent hole in it.

If that vent tube becomes blocked by debris thrown up by the wheels or the vent in the filler cap becomes blocked, a partial vacuum builds up inside the tank. As the fuel level drops the vacuum 'holds it up' and restricts fuel flow to the engine.

A quick check is, when the car begins to splutter and die, is to quickly remove the fuel cap. If you hear air rushing into the tank you know that there was a partial vacuum inside.

Fuel Filter
A blocked fuel filter causes the same symptoms. However, you won't hear air rushing into the fuel tank when the filler cap is removed. There's no way of dealing with a fuel filter other than by replacing it with a new one.

A lot of fuel filter problems are caused by corrosion - that's corrosion from the tank and filler pipe itself. It blocks the fuel supply. It mainly applies to older cars but as the fuel filter is a service item it makes sense to change it every couple of years anyway.

Failing Fuel Pump

The most classic symptom of all.

In tank fuel pump -it lifts the fuel

The way to test a fuel pump is by disconnecting the fuel line that runs into the engine bay. Get somebody to turn the ignition on for you - and fuel should literally spurt out. Not trickle or dribble .. it should spurt out.


inline fuel pump pushes the fuel. Usually this type of pump is fitted underneath the vehicle or in the engine compartment

However, herein lies a problem. Fuel pumps that are nearing the end of their lifespan still work - it's those erratic moments when they stop pumping your car splutters and slows down. An erratic, failing fuel pump can still throw fuel out of a disconnected fuel line. You're no further forward.

Other than pressure testing the fuel supply a workshop can not do much else that you can not do. They certainly won't remove the fuel pump from the tank and test it. They would simply replace it. You would have to do the same if you suspected the fuel pump was failing and causing the problems.

Usually, the fuel pump is situated in the fuel tank. Access is via an inspection cover that is screwed to the top and accessible from inside the car (usually).
Some vehicles have two fuel pumps. There is the pump in the tank which lifts the fuel into the fuel line. The second fuel pump - either fitted underneath the vehicle or in the engine bay - pushes the fuel up to the injectors.

The in-tank fuel pump is accessed from within the vehicle
In such twin-fuel pump systems it is usually the in-tank lifter pump that fails, simply because it is the one that does the hard work.


Mechanical Fuel Pump
There's still a lot of mechanical fuel pumps around,admittedly on older vehicles. They're bolted onto the side of the engine block and driven by a cam - the arm on the fuel pump is spring loaded. The cam causes the arm to operate, moving a diaphragm inside the pump which shoves fuel up to the engine.

The two main faults associated with the mechanical fuel pump: the diaphragm splits and perishes due to age. It becomes incapable of pumping fuel (replacement diaphragms are still available).

That spring loaded arm wears a groove in the cam and it- the arm - no longer has the 'reach' and full range of movement. A get-you-home fix is to remove the gasket so that the arm can reach further into the block. And that's all it is - a get you home fix.

It's actually easier to fit and adapt an electric fuel pump than it is to replace the worn cam that drives the mechanical fuel pump's arm.

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acts like its running out of fuel


p { margin-bottom: 0.25cm; line-height: 120%; } My Car Drives and Then Cuts Out. It Restarts After a Couple Of Minutes
Your car starts and drives okay and then suddenly, it splutters and slows down and then picks up speed again. Or it slows down, splutters and then dies. The fault is erratic: some days the car drives perfectly at all speeds and other times, the symptoms reappear. There's no warning lights on the dashboard. Sound familiar?

It could be caused by a sensor failure, yes, but the symptoms are also classic signs of :
1. A partial vacuum in the fuel tank
2. Blocked fuel filter
3. A failing fuel pump.

Partial Vacuum
Fuel tanks are vented to atmosphere. Air should be able to get into the tank. To achieve this the tank has a small tube which probably appears somewhere underneath the car in the vicinity of one of the rear wheels, or the fuel filler cap itself has a small vent hole in it.

If that vent tube becomes blocked by debris thrown up by the wheels or the vent in the filler cap becomes blocked, a partial vacuum builds up inside the tank. As the fuel level drops the vacuum 'holds it up' and restricts fuel flow to the engine.

A quick check is, when the car begins to splutter and die, is to quickly remove the fuel cap. If you hear air rushing into the tank you know that there was a partial vacuum inside.

Fuel Filter
A blocked fuel filter causes the same symptoms. However, you won't hear air rushing into the fuel tank when the filler cap is removed. There's no way of dealing with a fuel filter other than by replacing it with a new one.

A lot of fuel filter problems are caused by corrosion - that's corrosion from the tank and filler pipe itself. It blocks the fuel supply. It mainly applies to older cars but as the fuel filter is a service item it makes sense to change it every couple of years anyway.

Failing Fuel Pump

The most classic symptom of all.

The way to test a fuel pump is by disconnecting the fuel line that runs into the engine bay. Get somebody to turn the ignition on for you - and fuel should literally spurt out. Not trickle or dribble .. it should spurt out.

However, herein lies a problem. Fuel pumps that are nearing the end of their lifespan still work - it's those erratic moments when they stop pumping your car splutters and slows down. An erratic, failing fuel pump can still throw fuel out of a disconnected fuel line. You're no further forward.

Other than pressure testing the fuel supply a workshop can not do much else that you can not do. They certainly won't remove the fuel pump from the tank and test it. They would simply replace it. You would have to do the same if you suspected the fuel pump was failing and causing the problems.

Usually, the fuel pump is situated in the fuel tank. Access is via an inspection cover that is screwed to the top and accesible from inside the car (usually).
Some vehicles have two fuel pumps. There is the pump in the tank which lifts the fuel into the fuel line. The second fuel pump - either fitted underneath the vehicle or in the engine bay - pushes the fuel up to the injectors.

In such twin-fuel pump systems it is usually the in-tank lifter pump that fails, simply because it is the one that does the hard work.

Oct 15, 2015 | 2003 Dodge Caravan

1 Answer

1997 Trans am Cuts off then restarts shut down later


I have experienced a car with a heat sensitive crankshaft sensor so I would opt for that as my first choice. I doubt the fuel pressure regulator would cause your problem but it could be the fuel pump or water or dirt in the fuel tank.

Nov 07, 2017 | 1995 Pontiac Firebird

1 Answer

Engine cuts out and will not start again


As with any no start issue, you will need to find out if you are dealing with a no spark or no fuel problem to proceed.

Aug 17, 2012 | 1995 Volkswagen Golf

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