Can spark plugs cause idle surge?
3. 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 causes a car to have an idle surge?
Air Supply A clogged or obstructed air filter can cause surging at idle, and foreign objects can enter the filter housing at any time. Any debris in the filter or housing might restrict air flow to the engine enough to affect idle speeds. Fuel filters can become restricted and deny proper delivery at idle speeds.
What causes the engine to surge at low speeds?
Idle Speed Control Issues On some models, a faulty or fouled idle speed control (ISC) motor [or idle air control (IAC) motor] may cause the engine to surge at idle or at low speeds. A common problem is carbon buildup. It prevents air to bypass the throttle plate as commanded by the car’s computer.
Can a vacuum leak cause an idle surge?
Idle solenoids or controls should be adjusted to specifications after vacuum leaks are repaired. Ignition system problems can contribute to idle surge. Ignition timing and the condition of spark plugs and related components should be be checked before seeking professional assistance.
What happens when engine idle speed is above programmed range?
When the engine idle speed is either above or below the programmed range, the ECU prompts the ISC to either increase or decrease bypass airflow. Naturally, as the IAC prompts the throttle plate to open, engine speed increases. The IAC features a plunger mechanism that may be stuck/sticking.
What would cause the engine to surge at idle?
The Causes of an Idle Surge Air Supply. A clogged or obstructed air filter can cause surging at idle, and foreign objects can enter the filter housing at any time. Fuel Supply. Fuel filters can become restricted and deny proper delivery at idle speeds. Vacuum. Any extra air entering the intake manifold will lean the mixture at idle and surging will result. Engine Issues.
Why does the engine surge at idle?
An idle surge can be caused by multiple phenomena. 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.
When is idle it surges?
Cold weather can cause your generator to surge at idle sometimes for 10 minutes or more until things really start warming up. When the temperature is cold, gasoline does not vaporize quickly at all and you may need to leave your unit on half-choke for a long time until it reaches that point.
Is low idle bad?
A compression check is highly recommended to ensure you’re not messing with a hurt motor. Low compression will cause a bad or low idle. In most cases, it is intake vacuum leaks that is the most likely source of the problems.