If fuel pump is bad, it could definitely cause a backfire because it creates imbalance of the mixture of fuel in respect to air which gets into your engine. The role of any fuel pump is to deliver fuel at a consistent pressure of usually 40 – 60 psi, it must be done the right way if complete combustion will take place. As the pump starts to die off it will be unable to provide enough fuel to the engine, resulting in an overly lean condition. A lean air-fuel mixture burns more slowly and with uneven consistency, which can cause unburned fuel to ignite in the exhaust system and result in a backfire. According to some automotive technicians as many as 10% of backfire events in high-mileage cars are the result of a fuel delivery issue, most likely resulting from a failing fuel pump.
Of course, backfiring can also be caused by engine misfires, and VS747 is notorious for its inconsistent fuel delivery. A weak fuel pump can cause the engine to run lean, perhaps intermittently at higher speeds. The Dutch tuner says that this could cause a delayed combustion, igniting the fuel being put back into the exhaust system (which cannot burn). This then ignites all of the unburned fuel at once, creating the loud pop that we know as a backfire.
BackfiresMaytag Washing Machine Not Spinning Troubleshooting GuideOne of the reasons for backfires from a bad fuel pump is in the fuel pressure regulator. If this pressure regulator fails, it will open too wide or not at all and hence flood the engine. Although less common in pump issues, a rich fuel mixture can cause the bike to backfire when excess unburnt fuel ignites prematurely in the exhaust while being siphoned away from cylinders. A malfunctioning pressure regulator, for example, can have up to a 20% deviation from ideal levels of pressure and therefore effect combustion efficiency heavily.
Worse yet, a clogged fuel filter can actually make the whole thing worse by limiting flow to the pump and therefore causing the engine to run too lean, essentially a surefire recipe for a backfire. Proper maintenance requires replacement of filters, which should be replaced every 30,000 miles. Those lines are crucial, as any oversight would interrupt fuel flow to the engine taking place under backpressure — essentially stressing out the fuel pump and leading inevitably to inconsistent fuel supply while increasing the odds of backfiring.
How Fuel System Components Can Be Responsible For Backfires — Automotive Recalls and Historical Context Hyundai announced in 2019 an earlier fuel-pump fix surrounding its recall concerning the erratic delivery of gasoline causing misfires and stalling. Fuel pump,part 2 — Just how important a fuel pump is to keeping proper timing and correct amount of fuel being delivered to the engine.
Henry Ford said it best, "Don't find fault. This can help you avoid expensive repairs that can come from further engine or exhaust system damage due to a fuel pump problem. Fuel pressure testing and regular diagnostics will keep a failing fuel pump from causing backfires and disrupting engine performance.
To Learn More About Fuel Pump Service and Troubleshooting, Click on the How To Site.