What causes a car to stall only at idle?
Often, engines that stall only at idle do so because they’re getting either too much air, or not enough fuel. Leaking vacuum lines and intake induction parts are the classic suspects, but these days you have to account for exhaust gas recirculation valves stuck in the open position, and idle air control valves doing the same.
Why is idle speed not coming back up?
If the ISC system is working correctly, the PCM should adjust idle speed to keep the engine from lugging down when the A/C compressor engages. If idle speed drops down and does not come back up, the ISC system is not responding the way it should.
Can a stalling engine be intermittent driveability?
Intermittent driveability problems of any kind are always a challenge to diagnose. When a customer brings you a vehicle and complains of a stalling problem, you may not have much to go on other than their description of what’s happening and when it happens.
What should the fuel pressure be at idle?
Fuel pressure should be within specifications when the key is on, then drop 4 to 6 psi once the engine starts and is idling. Note: Some vehicle manufacturers list pressure specifications for both KOEO and idle, while others only list a fuel pressure specification for one or the other.
What causes an engine to stall at idle?
If the ISC valve is gummed up with fuel varnish or dirt, it may stick, preventing the engine from maintaining the proper idle speed when the throttle closes. A faulty idle speed control circuit may also allow the engine to stall when idling if it fails to compensate for idle loads placed on the engine by the charging system or A/C compressor.
If the ISC system is working correctly, the PCM should adjust idle speed to keep the engine from lugging down when the A/C compressor engages. If idle speed drops down and does not come back up, the ISC system is not responding the way it should.
Intermittent driveability problems of any kind are always a challenge to diagnose. When a customer brings you a vehicle and complains of a stalling problem, you may not have much to go on other than their description of what’s happening and when it happens.
Fuel pressure should be within specifications when the key is on, then drop 4 to 6 psi once the engine starts and is idling. Note: Some vehicle manufacturers list pressure specifications for both KOEO and idle, while others only list a fuel pressure specification for one or the other.
When does the idle air control valve stall?
However, when the engine RPM drops below the normal range of 800 RPM (for most cars), it is more than likely that you are dealing with an IAC valve problem. In cases where this valve is clogged or is nearing its replacement age, your vehicle will stall instead of idling after the release of the throttle.
What to do if your car rough Idles?
In cases where this valve is clogged or is nearing its replacement age, your vehicle will stall instead of idling after the release of the throttle. If you’d like assistance with this issue, a certified YourMechanic technician can come to your location to help inspect your vehicle’s rough idle or replace the IAC valve for you.
What causes a car to stall at idle?
The way diesel engines produce power is different from gasoline engines. Every time the injectors push fuel and air into the chamber, the spark plugs deliver the electrical current. This keeps the engine running. If you have a weak or poor quality spark plug, then it is possible that it will lead to car stalling.
What to do if your car won’t idle?
The Fix: Set idle speed to specs. There may be some type of ignition problem. The Fix: Check and replace distributor cap, rotor, ignition wires, and spark plugs. There may be a fault in the computerized engine control system. The Fix: Bring your car to your mechanic or dealership to check the engine control system with a scan tool.
What to do if your Harley Davidson engine stalls?
Mist the intake flanges with brake cleaner. If your bike’s idle drops, or the engine stalls, you have an intake leak. If this is the case, replace the intake seals along with the front & rear intake flanges. If the bike passes the intake test; have the dealer or your mechanic scan the m/c for possible codes.
Why does my bike stall after a ride?
The bike starts fine when cold and runs perfect through all RPM ranges. After riding a while and it is hot it will stall at idle but starts back up with no problem. It just will not idle. It will also return to normal and idle fine after stopping for lunch. It sometimes is fine for the rest of the ride. Any Ideas? Check for trouble codes.