grumpyvette
retired mech engineer
locating those intake manifold or other vacuum leaks
yeah the way I find vacuum leaks on carb OR MPFI intake manifolds is clean and easy with no mess. get a propane torch,or you can use your oxy-acetolene welding torch if you have one, (DON,T TURN THE OXY tank/or valve ON)
(DONT LIGHT IT) just SLIGHTLY open the valve so its allowing gas to flow at a low voluum,start the engine and let it idle at the lowest speed you can then place the tip of the UNLIT torch at any suspected vacuum leak and listen for the rpms to increase and watch the tach, gas flowing into a vacuum leak will increase engine speed.
look for loose or missing vacuum hoses, cracked or broken power brake connections, emmisions system hoses that are loose, vacuum connections to the trans or ignition, loose connectors missing or loose bolts cracked hoses missing assessory connections etc.
yeah the way I find vacuum leaks on carb OR MPFI intake manifolds is clean and easy with no mess. get a propane torch,or you can use your oxy-acetolene welding torch if you have one, (DON,T TURN THE OXY tank/or valve ON)
(DONT LIGHT IT) just SLIGHTLY open the valve so its allowing gas to flow at a low voluum,start the engine and let it idle at the lowest speed you can then place the tip of the UNLIT torch at any suspected vacuum leak and listen for the rpms to increase and watch the tach, gas flowing into a vacuum leak will increase engine speed.
look for loose or missing vacuum hoses, cracked or broken power brake connections, emmisions system hoses that are loose, vacuum connections to the trans or ignition, loose connectors missing or loose bolts cracked hoses missing assessory connections etc.