What causes an engine surge during fuel injection?
In combination with the camshaft position sensor (CMP), the CKP signals are used by the ECU to manage fuel injection and spark delivery. A faulty CKP (or CKP circuit) can easily cause an intermittent misfire, which naturally results in what the driver may perceive as a surging effect.
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 causes an engine surge when the ECU is off?
If closed TPS voltage changes, the ECU may assume that your foot is on the throttle, causing a richer fuel mixture to be delivered. This can also be caused by a faulty TPS, or even a poor ground. With the engine off, check TPS voltage with the accelerator pedal relaxed. Then work the pedal a few times and see if the voltage changes.
What causes an engine to idle up and down?
A malfunctioning MAF sensor can cause a wild up/down engine idle speed (say, 0-2,000 rpm). This might be caused by a loose harness connection or by a damaged or contaminated sensing wire. The MAF sensor measures the amount of air flowing through the throttle valve.
What are the symptoms of a rough idle engine?
It is possible for you to test the EGR valve at home, using a hand held vacuum pump. Other symptoms: An EGR stuck open may include a rough idle, rough performance at low engine speeds, stalling at idle, increase in fuel consumption, fuel odors, and possibly a check engine light on. 4. MAF Sensor
Why is my engine surging at low rpm?
The fuel pressure regulator may be operating at, low pressure. Check fuel pressure with a fuel pressure gauge. Replace fuel pressure regulator. Your ignition timing may be set incorrectly. Check and adjust, ignition timing. Ignition system problem causing a, weak spark.
What causes the engine to surging while cruising?
A vacuum leak in a MAP system can cause engine surging while cruising. Oxidation of gasoline after spending some time in storage is a natural process. Gasoline will react with oxygen to produce carbon dioxide, water and contaminants like nitric oxides and loose carbon molecules, losing its potency.
Why is the EGR valve open at idle?
It is when the valve remains open when engine idle suffers. Sometimes, the engine may stall at idle because of the lean of the air-fuel mixture. It is possible for you to test the EGR valve at home, using a hand held vacuum pump.