What happens when an ignition module goes bad?
Overheating. Ignition modules that are overheating will soon completely cease to function and in the meantime can cause cause electrical shorts, engine stuttering, lower gas mileage, power loss, stalling, and gasoline odors in the exhaust. You can test for overheating while the car still runs.
What causes an engine to stall while idling?
This can upset the air/fuel mixture causing idle, stalling and hesitation problems. Cleaning the airflow sensor wire with aerosol electronics cleaner; can often restore normal operation and cure the problem. If the engine stalls while idling or driving, the engine may be running out of fuel.
Is there check engine light for intermittent stalling?
Many times, there will be no check engine light and no fault codes to give you a clue as to what might be causing the engine to stall. So the trick to diagnosing an intermittent stalling problem is to catch the vehicle when it’s acting up — and that rarely happens when you have the vehicle in your shop.
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 causes intermittent stalling in a car engine?
More Causes. One of the more unusual causes of intermittent stalling we’ve heard about is a defective vehicle speed sensor. When the vehicle stops moving, the PCM may not engage the idle speed motor (carbureted engines) or idle air bypass motor (fuel injected engines) so the engine will idle normally.
Why does my PCM stall when I Turn on the engine?
The MAP sensor senses intake vacuum, which the PCM uses to estimate load so it can adjust the air/fuel mixture accordingly. If the MAP sensor isn’t reading right, the PCM will receive bad information and possibly add or subtract more fuel than it should causing the engine to stall.
What causes a car to stall after replacing the relay?
Replacing the relay usually cures the problem. Another cause of stalling that is often overlooked is bad gas. Moisture sometimes finds its way into underground fuel tanks, and engines don’t run very well on water. Sometimes alcohol additives may not be properly mixed, or may separate from the gasoline in the presence of water.
Why does the engine stall when the a / C is on?
Normally, the PCM should increase the idle speed to compensate for the added load on the engine when the A/C is on. But if the A/C signal fails to reach the PCM because of a communications glitch between the A/C module and PCM, the PCM may fail to increase idle speed causing the engine to lug or stall.