The Starter That Turns in a Vacuum



– The problem of a starter running in a vacuum

– Causes of a starter running in a vacuum

– What to do when the starter runs in a vacuum

– Starter Repair and cost

In this post, you’ll learn about the starter motor that turns in a vacuum. You turn the key or push the start button on your car, and the engine won’t start, but you hear the starter motor running. What’s going on?

Idling starter problem

Despite your insistence on turning the key all the way around or pressing the engine start button, nothing happens! You can still hear the starter motor turning, but it seems to be turning in a vacuum. This tells you the engine itself has not failed. Now you need to find out what’s causing the problem.

Causes of astarter running in a vacuum

Does Your Car Starter Unit Need Repairs

The causes of the problem can be diverse. As always in mechanical matters, think of the simplest possibilities first:

– The starter motor is running too slowly because of a weak battery.

– The electrical polarity is reversed because the power and ground cables were connected to the battery on the wrong terminals.

– gas is not getting into the gas injection system or carburetor.

– There is an ignition failure.

Then there are more complex causes that require specific mechanical intervention:

– The pinion gear is dirty, or its teeth are worn or broken.

– The starter ring gear teeth are worn or broken.

– Worn or broken flywheel gear teeth.

– The starter motor clutch is slipping.

What should I do if the starter motor spins in a vacuum?


If the starter motor is running too slowly to start the car’s engine, the battery is nearly discharged. If you have the opportunity, you can remedy the problem in one of the following ways:

  • Connect your car’s battery to another battery in good condition or another car’s battery (engine running) via jumper cables. Be careful not to make a mistake in polarity by connecting the red cable (positive) to the 2 positive terminals of the batteries indicated by a “+” and the 2 black cables to the negative terminals marked by a “-“. Wait 2 or 3 minutes for the defective battery to be slightly recharged before attempting to restart your car.
  • Replace the discharged battery in your car with a new one. Suppose you have replaced the battery incorrectly (the + and – poles mentioned above). You may have connected the positive cable to the negative terminal and the negative cable to the positive terminal. In this case, reverse the connection of your cables so that they are connected to the correct terminals.

Warning: before buying a new battery, make sure that the poles of the new battery are the same as the old one. Depending on the application of each car, the battery poles are not necessarily in the same place. Take your vehicle registration document with you to have the serial number; the seller will then provide you with a suitable model. Each model corresponds to specific motorization.

  • Gas may not be reaching the injection system or your engine’s carburetor. The first way to be sure is to turn on the ignition without starting the engine. If you can hear the sound of the electric gas pump, it is working. You may then be facing an injection failure. In this case, all you have to do is have your vehicle towed to a garage for a confirmed diagnosis.

If you have an older vehicle equipped with a carburetor and powered by a mechanical gas pump, and there is a small gas filter between the pump and the carburetor, proceed as follows:

– assisted by another person turning the ignition key, see if the gas filter fills or not;

– If there is no gas filter, disconnect the gas filler hose from the carburetor, ask the person next to you to turn the key, and check that gas is flowing through the hose. As soon as you see gas coming out, ask your companion to stop turning the key immediately to avoid getting gasoline everywhere.

Important: in the case of an ignition failure, there is no way to verify its origin if you are not yourself an electronics expert and equipped with the necessary equipment to check its operation. Towing to a specialist is then required.

Repair and cost of the starter motor that runs in a vacuum

starter motor

In situations requiring major mechanical work, for which you will have to take the car to a mechanic, there are two options

– the starter motor can be replaced outright;

– disassembling it, analyzing the condition of its components, and replacing the defective ones.

In both cases, the mechanic will provide an estimate of the cost.

Please note: the starter price ranges from $80 to $170, excluding assembly…

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