How do I fix a vacum leak on 2002 nissam sentra gxe
You have to find the leak and seal it up, hey. It may help to picture where vacuum originates in the engine: As the pistons move down in the cylinders they pull air in from the intake manifold. This creates a pressure drop in the intake, a vacuum that is maintained as the engine is running. New air that is pulled into the intake is measured by the Mass Air Flow sensor mounted in the big boot between the air filter and the intake. If extra air is pulled into the intake manifold from a vacuum leak, uncalibrated air, the computer can figure it out from the oxygen sensors reading in the exhaust-mixture is too lean, so the computer will try to compensate by delivering more fuel, but can't deliver enough, mix is still too lean, so computer sets a code for the vacuum leak.
The intake will have a few vacuum taps with hoses running to engine or car controls that require vacuum to operate. If one of the hoses comes off or has a leak, that is extra air into the intake. Your power brake booster has a large vacuum tap. That may be the problem. With the engine running, pull off that line and plug it, and see if engine speed changes. If the idle drops that may be your leak-a failed power brake booster.
If nothing yet, keep engine running and spray some starting fluid around the mounting area of the intake manifold (maybe the intake gasket has failed and sprung a leak) and listen for a change in engine pitch or speed. The fluid may get sucked into the intake and cause speed to change. If it does, you would need to remove the intake manifold and fit a new manifold gasket.
Also check the big boot from the air filter to the throttle body for tears or loose fit. Good luck, Rev!
Nov 30, 2012 |
Cars & Trucks