This leads to wonky fuel delivery and it can cause rough idle in your car. Most modern internal combustion engines run smoothly if they have an air-to-fuel ratio close to 14.7:1. If the Fuel Pump does not supply fuel precisely, this ratio is unbalanced, and the vehicle experiences rough idle. This can lead to as much as a 15% reduction in engine efficiency, affecting performance at all RPMs, but usually most perceptibly at idle.
Most of the time, a rough idle happens when the Fuel Pump can not keep the pressure. For instance, most gasoline engines need a minimum of 40 PSI fuel pressure. It runs at that pressure until pump wear, clogs, or electrical problems cause the pressure to drop, which results in engine misfires, hesitation, or inconsistent RPMs. In cold weather these symptoms become more evident, as fuel systems are needing more energy to maintain flow-rates.
This is a common problem auto shops deal with in high-mileage vehicles. A 2022 industry report indicated that more than one in every five vehicles complained about a rough idle and had a fuel system-related problem, causing the Fuel Pump to be found in 12% of all cases. One notable case of a defective Fuel Pump leading to mass inconvenience occurred in 2020, when a popular automaker issued a recall impacting over 1.5 million cars that suffered from widespread engine idling problems and unexpected stalls.
In such cases, repairing or replacing a defect Fuel Pump can fix rough idle and may also prevent wrecking your engine. Fuel Pump parts alone can cost on average between $300 and $700, depending on the vehicle model and labor rates. This is a far cry from the consequences of secondary damages starting from burnt valves, clogged injectors etc which can run into repair bills of over $2,000.
Rough idling isn’t just a nuisance; it’s a symptom of something that can potentially become a safety risk or cause a breakdown if not addressed. As carmaker and engineer Carroll Shelby once said, “The driver’s best tool is the machine’s reliability.” By keeping your Fuel Pump working properly and addressing problems quickly, you can keep your engine running and save money on long-term repairs.
Mechanics commonly know that a Fuel Pump is failing when a fuel pressure gauge indicates a performance problem. An ideal pressure reading will be exactly in the specs mentioned in your vehicle’s service manual. If the pressure varies a lot at idle, you need a new pump. Good suppliers such as Fuel Pump provide options for maintaining steady engine performance. Regular maintenance of the Fuel Pump can help you in keeping your vehicle fine-tuned and away from the challenges of a rough start.