Why your Engine Stalls
A damaged part, a failing-or bad-electronic component, or something as simple as a system requiring maintenance can cause anengine to stall. But, if you don't know how to troubleshoot for engine performance problems, you can easily spend a lot of money-and time-just swapping components, trying to fix the problem unsuccessfully. And end up frustrated. Yet, even if you don't have much experience fixing cars, a simple strategy will increase your chances of repairing your engine.Looking for vacuum leaksVacuum leaks can easily stall an engine, says James E. Duffy in Modern Automotive Technology. A leak may come from a deteriorated, damaged or disconnected vacuum hose. Open the hood and closely examine every vacuum hose connected to the engine andthrottle body. Look for a cracked, torn, loose or disconnected hose.If your engine can run at idle, start it and listen for a hissing sound to locate its source. Use a piece of rubber hose for best results. Put one hose end against your ear and move the other end along the various vacuum hoses and around the intake manifold to check for gasket leaks as well. When you hear a loud hissing sound, you've found the leak.Systems in need of maintenanceOften, a neglected system may cause a stalling problem. Pay particular attention to the air intake and fuel systems. Have you changed the air or fuel filter within the past twelve months? If not, you may have a restricted or clogged element.You may become aware of this type of problem when driving at highway speeds. As the engine demand for air and fuel increases, a partially clogged air or fuel system will fail to satisfy the demand, causing engine performance problems, even stalling.Check your car owner's or service manual for the air and fuel filters service interval. If the change is overdue, it won't hurt replacing them. This may fix your problem.Clogged systemsRestricted air passages in the throttle body or idle air control (IAC) system, and bad or failing electronic components can also stall an otherwise healthy engine. Over time, sludge builds up-and starts to clog-air passages around the throttle body's plate and the IAC solenoid. When the problem becomes severe, you'll notice a rough idle, or the engine will simply stall soon after starting.Is there too much buildup around the throttle body or IAC system? Apply some intake and/or carburetor cleaner. Follow the directions on the product's package to clean those systems in your vehicle.Bad electrical componentsYour car computer uses the idle air control solenoid-and other engine sensors-to manage engine rpm during the warm up period. They can become a problem as well. When the IAC solenoid can't respond, or a sensor fails to send the correct information to the computer, the engine may stall. Usually, bad electrical/electronic components will trigger the check engine light on your dashboard. Don't ignore it!Connect a scan reader to the data link connector of yourcar's computerand follow your tool manufacturer instructions to retrieve any trouble codes stored in the computer's memory. If you don't have a reader or scan tool, one of your local auto parts store may retrieve these codes for you and tell you in which system lays the problem. Some auto part stores provide this service for free.Whenever you need to find out why your engine stalls, try following a simple strategy first. That and some help from your service or repair manual-if necessary-can help you inspect and repair your stalling engine. Start with the most simple (a vacuum hose problem) or logical step (a system in need of maintenance or a triggered check engine light). In many cases, this strategy will help you solve your problem-and save you a lot of trouble and money. You'll be glad you tried it out.
