Why does my engine rev up when idle?
If gunge builds up on the butterfly valve, it can restrict the air required for a smooth idle when the butterfly is closed, so the engine ECU needs to open the Idle Air Valve more that it thinks it should have to and you get into a cycle of surging revs.
Why do I get a Rev hang when I idle?
Modified, bored out throttle bodies with poorly sealing throttle plates, or drilled throttle plates are also a common cause of rev hang issues. To identify the possible cause, use a can of Aerostart or similar spray and go around all seals on the intake side of the engine. If the idle changes when you spray a seal, you have found the leak.
What should the idle RPM be while idling?
You can get a cheap gauge at an auto part place that will quickly tell you if you are in spec. Idle air control..it should idle at 1000 rpm’s when the engine rpm’s jump up and down,suspect the iac. Thanks for contributing an answer to Motor Vehicle Maintenance & Repair Stack Exchange! Please be sure to answer the question.
What causes idle to change on EA-AU Falcon?
If the idle changes when you spray a seal, you have found the leak. The second most likely cause is a poorly adjusted base idle. This should only be adjusted after checking for air leaks as above. To correctly set the base idle on an EA-AU Falcon: With a fully warm engine, disconnect the Idle Speed Control (ISC) valve electrical connector.
Why does my RPM drop when sitting idle at traffic lights?
While I’m sitting idle at traffic lights I put the car into neutral. The engine stays idling at about 1000 RPM. However every now and then it drops down to about 500 RPM and then quickly back up to about 1200 then goes slowly down to 1000 and stays there for a bit until I go again or it drops again.
What should I do if my car idles for no reason?
Replacing a vacuum hose is typically inexpensive because it’s just a small piece of rube hose. The bad news with a vacuum leak is that it can sometimes be tough to track down which hose is causing the vacuum leak. You may have to perform a smoke test or spray carb cleaner onto your vacuum lines to listen for a change in your engine idle speed.
Why is my car revving up and down?
Another reason for a rough idle or your car revving up and down on its own can be a plugged EGR valve. Your EGR valve is connected to your EGR (Exhaust Gas Recirculation) system which was developed to help manufacturers pass ever-increasing emissions standards.
Why does my car rev up and down at idle?
Over time the throttle body valve can become dirty which can allow the throttle body valve to stick or not open/close all the way which can cause your car’s engine to rev erratically and can cause the engine idle to bounce up and down.
What happens if the idle level is too low?
Idle level too low. If the idle level on your (warmed up) engine is lower than the level decided by the manufactorer, you will usually have two problems: – The oil pressure inside the engine will be very low, and you may see the oil pressure lamp flicker. – Charcoal cannister in the tank ventilation line clogged by fuel or dirt.
Why is the idle air control valve not working?
When this happens, the job of the idle air control valve is to bring this deceleration down to a slow and smooth idle rather than suddenly cutting off the fuel supply causing the motor to die. When the idle air control valve is not working properly, this cause a disruption in this process resulting in the engine not being able to idle properly.
What causes my car to idle and stall?
Hi There, It sounds like you may have a dirty or failing idle air control valve causing your engine idle to fluctuate and eventually stall. The idle air control valve is a small valve on the engine’s intake system that reads the air intake as it comes into the motor.
Is the throttle internals of a gasoline engine Dirty?
I am presuming this is a gasoline engine. If so, the symptoms sound very much like the throttle internals are dirty.
What causes an ignition coil to misfire in a car?
The most common problem when it comes to misfires is the ignition coil. Some vehicles have a separate ignition coil on each spark plug, while some cars have one coil with a sparking cable to each spark plug. Older cars have a distributor and, in some cases, also an ignition coil.