If an engine is not getting enough fuel (this is called “running lean”), due to fuel pressure (regulated by the fuel pump and regulator), restricted fuel injectors, a vacuum leak or really anything that throws off the fuel mixture going in to the engine, this can cause the surge.
What does engine surging mean?
Engine surging is different from a difficult start or a no-start problem. “Surging” does not refer to a knocking engine or one that idles rough or stalls. Engine surging is when an engine starts easily and accelerates smoothly, however after a few minutes at a steady speed, it either surges in speed or misfires.
Can bad spark plugs cause surging?
Surging and Lagging
Another good indication that your spark plugs are dirty or worn is if your vehicle experiences surges of speed, resulting in a jerking acceleration. These surges occur because your spark plugs are not igniting the fuel in your engine at the proper rate, resulting in an uneven speed.
What does engine surging feel like?
You may notice the tachometer fluctuating, for example, from 1500 to 2000 rpm. At the same time, you may feel a soft and rhythmic jerking motion. The problem may come from a faulty sensor or system that is making the computer deliver too much or too little fuel, and then try to correct the fault by over-compensating.
How do you fix a surging idle?
The cure for this condition is to clean the valve with some aerosol throttle cleaner or engine top cleaner. Here’s how to clean the IAC valve: Disconnect the air intake ductwork from the throttle body. Start the engine, then increase and hold the idle speed to 1,000 to 1,500 rpm.
Can a bad O2 sensor cause surging?
While you’re cruising down the road, O2 sensor hunting will manifest as a constant surging. This surging can be extremely disconcerting if you happen to be prone to motion sickness, since the constant acceleration and deceleration feels something like riding a boat through heavy seas.
What causes surging in a small engine?
This vent is just large enough to allow air into the tank, creating enough backpressure to aid in fuel delivery to the carburetor. … Surging is also caused by water that got into the fuel. A mower left in a heavy rain or condensation on a hot summer day can choke the engine.
Why are my rpms surging?
Hi there. For the engine surging making the rpm’s go up and down could be caused by a defective or stuck idle air control valve (IAC). … To calibrate the throttle pedal position sensor, turn on the key with the engine off and push the gas pedal to the floor slowly. Hold the pedal on the floor and turn off the key.
Can a bad fuel filter cause surging?
A badly clogged fuel filter will reduce fuel pressure enough that the ECM must open the fuel injectors more to maintain the same amount of flow. … Fuel injectors contain very fine mesh filters, which can just as easily clog and cause the same sort of surging.
Can a bad fuel pump cause surging?
Irregular resistance inside the fuel pump motor may cause vehicle surging, and indicates a fuel pump in need of repair. Surging feels like the gas pedal has been used. However, it occurs at a random, consistent speed. If this happens often, it may be because of problems within the fuel pump.
What is engine surge or hesitation?
Hesitation Definition – An engine hesitation is an interruption of continuous power during acceleration. When a engine is hesitating it will cause the car to lunge or surge which will cause a sudden jerk as the car slows down.
What is a surging transmission?
A surging transmission, a transmission that causes a vehicle to lurch forward and then fall backward during normal operation, is often the result of a low transmission fluid level. The surging and erratic transmission movements are caused by insufficient fluid force during all ranges of transmission operation.
Is it normal for RPM to fluctuate?
For the engine surging making the rpm’s go up and down could be caused by a defective or stuck idle air control valve (IAC). Check the IAC and see if it’s working. Remove the vacuum line to the valve and see if the engine runs smooth.
What causes RPM to fluctuate while idling?
Why does my engine’s RPM seem to fluctuate (runs rough)?
Engine hunting and surging at idle is usually caused by a fuel delivery, air leak, or governor system problem. Cleaning/overhauling the carburettor, adjustment of the governor, and/or changing the air filer may be required.
What can cause erratic idle?
Erratic engine idle can be caused by various factors, but the most common and likely cause is a dirty or malfunctioning Mass Air Flow (MAF) sensor. This is a device found in fuel-injected cars and measures air flow so that the appropriate amount of fuel can be injected.
What causes rough idle and hesitation?
Rough idling can also be caused by clogged filters. … Bad spark plugs, bad spark plug wires and a bad distributor cap are other common causes of rough idling. These items are all important parts of what keeps a vehicle running. Spark plugs provide the spark that ignites the air and fuel mixture within the cylinders.