How to Repair Engine Surging Problems

An engine or motor surge is caused by an imbalance in the computer system which cannot be corrected within the parameters of the vehicle's operating program, in other words there is a mechanical problem. In the guide below we show you the most popular issues and how to fix them, EV's also have surging issues which we address in this guide.

Let's Jump In!

Anytime you have an issue like engine surging it is best to gather the trouble codes even if you don't have a check engine light on, this can help point us in the right direction or area that is causing the problem, the check engine light may not be on if there is a soft code.
read trouble codes

The mass air flow sensor (MAF) or manifold absolute pressure sensor (MAP) is used to send feedback data to the computer to help make timing and fuel adjustments. When these sensors go bad they can omit false information causing the computer to make incorrect adjustments which produce an engine surge. Sometimes you can clean the MAF which can help but we have found replacing the mass air flow sensor is best. This problem does not cause a trouble code because the sensor is still within its parameters, the value the sensor is outputting is just not correct for the engine's speed. This can be confirmed by reading the value using a scanner and then installing a new sensor and recording the difference to confirm the issue.
new maf sensor

The computer system is designed to work with specific vacuum values and when there is a vacuum leak the computer makes adjustments accordingly, which can produce a noticeable surge. Most of the time you can find this issue with a visual inspection, but if not there are two main methods which involve a smoke machine or the cheaper alternative, carburetor cleaner.
vacuum leak

An engine's fuel supply system is designed to operate at a specific pressure, when a fuel pump starts to age this pressure can decrease causing the pressure to fluctuate, as the computer tries to compensate, causing the engine to surge. A simple fuel pump pressure test can determine if this is the problem and if the fuel pump needs to be replaced.
fuel pressure test kit

The accelerator pedal position sensor is used to inform the computer on the intentional vehicle speed desired by the driver. When the sensor wears out due to normal usage it can vary the input to the computer for both EV's and gasoline vehicles alike. To confirm this issue a scanner is needed to monitor the input and look for fluctuations to confirm the issue and replace the sensor.

An EV's battery pack is made up of many low voltage cells connected in series, when one of these cells shorts out internally the output voltage of the battery pack will fluctuate affecting the motor speed. A scanner capable of monitoring the main battery pack voltage output is needed to find this problem and if found the battery pack will need to be replaced.


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