Why does my car rev high when I first turn it on?
Common causes of high RPM excursion at start-up are typically: large vacuum leak, throttle plate stuck open, cruise control stepper motor stuck in one position; faulty throttle position sensor, and/or faulty idle air control motor or solenoid.
Why does my car take a second to turn over?
A: Possible causes: a marginal battery, a poor connection in the starting circuit or starter, a charging-system problem, or the battery is being drained while the car’s parked. If the slow cranking occurs after driving (engine hot), it’s likely a faulty starter or poor charging.
When does an over rev occur in a car?
An over rev is exactly what is says it is. It is one or many engine revolutions over or above the maximum number of engine revolutions per minute the engine manufacturer has deemed safe. They typically occur in cars that have manual transmissions on down shifts when the road speed and gear tooth ratio are not in sync.
What does an over rev mean in software?
In some software applications, over-revs are classed as numbers or letters. This is to determine the limit or revolution the engine runs at and the number of times the engine ran at that speed. This tells the person reviewing the software just how bad the engine condition could be.
When do you start the car, the engine revs?
Car engine revs way up immediately upon starting engine. Q: Car engine revs way up immediately upon starting engine. When starting the engine, it sounds like you have your foot pressed to the floor on the gas pedal as soon as you start it, without even having your foot on the gas.
What are the signs of an over rev?
On the upwards stroke, the same happens to the lower bearing shells. Inspection of the shells often show the telltale signs of an over rev. Wear patterns on certain areas of the bearing along with length dimension changes will be noticeable. Often on the back side of the bearing shells, wear patterns will show.
Can bad spark plugs cause engine surging?
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.
Can a bad alternator cause engine surge?
So, for the archives, a bad or dead alternator can also definately cause idle surge.
Why is my engine surging?
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.
Can a bad alternator cause a rough idle?
Rough Running Drops in electrical output from a failing alternator can cause these systems to malfunction, leading to a poorly running engine. Symptoms will be rough idle, misfires, poor acceleration, hesitation and stalling.
What does it mean when your car is surging?
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. Misfiring happens when one of the cylinders of an engine’s combustion cycle fails. Since an engine has four cylinders, the car would still run if one cylinder fails.
How to troubleshoot a surge caused by car air?
Set the recirculation switch to off, so that outside air is coming in and drive the car with a temperature gauge in the dashboard vent. If the air conditioning is not performing well, the engine might be surging because the system is undercharged or overcharged. If it is overcharged, the load imposed by the compressor will be excessive.
What should I do if my engine is surging?
There may be a fault in the computerized engine control system. Check engine control systems with a scan tool. Have a mechanic test the circuits and repair or replace components as required, since this is generally not a DIY job. The fuel filter may be partially clogged. This is an easy fix! The fix: Replace the fuel filter.
Why is the engine surging when I idle the car?
My car has an automatic transmission. 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). Check the IAC and see if it’s working. Remove the vacuum line to the valve and see if the engine runs smooth. If the engine runs smooth, then the IAC needs to be replaced.