Posts Tagged: hunting idle
How does an idle air control valve work
What is an idle air control valve Many people are confused about how idle air control valves work. An idle air control valve literally bypasses air around a closed throttle plate so the engine can get air at idle. Because it bypasses air, it’s also called an air bypass valve. Back in the days of carburetors, idle speed was adjusted by way of an idle speed screw. In fact, on many carburetors there were two idle speed adjustment screws; one for hot idle and another for cold. Turning the screw … Read More
Bad idle air control valve
Bad idle air control valve symptoms Idle speed goes up and down or high idle First off, this is a fairly common problem for all makes and models. Sometimes the problem is caused by a gummed up or sticking idle air control valve (IAC) or a dirty mass airflow sensor (MAF). But it can also be caused by a vacuum leak. How an idle air control valve works If you’re familiar with older carbureted cars you remember that you turned a screw to set the idle speed. The screw turned … Read More