Connections for vacuum line to distributor - Cars & Trucks

If your 1991 Chevy's 4.3 Vortec engine has spark and fuel, but still fails to ignite, there are several possible reasons to consider. Timing: Make sure the burn time is set correctly. Incorrect timing can prevent the engine from starting. Double-check the timing marks to make sure they align properly. Compression: Make sure the engine has adequate compression. If the pressure is low in one or more cylinders, starting problems may occur. A compression test will help determine this. Fuel Delivery: Even though you said it has gas, pay close attention to the fuel delivery system. Make sure the fuel pump is working properly, the fuel filter is clean, and the fuel lines are not clogged or leaking. Air intake: Inspect air intake for blockages or leaks. A clogged air filter or leaking intake manifold gasket can affect engine performance. Vacuum leaks: Check the vacuum lines and connections for leaks. A vacuum leak can cause an uneven mixture of air and fuel and cause starting problems. Sensors: The engine relies on sensors to send information to the computer unit (ECU). Defective sensors such as the crankshaft position sensor or camshaft position sensor can prevent the engine from stalling. Wiring and connections: Ensure all electrical connections are secure and non-corrosive. Damaged wiring or loose connections can block signals to engine parts. ECU/PCM: The engine's computer (ECU/PCM) can be faulty, preventing proper signals from reaching the engine components. Distributor cap and rotor: If your engine uses a distributor, inspect the distributor cap and rotor for any signs of wear or damage.

If no vacuum on the line at the distributor, it will not advance but will start and run. Check connection of said vacuum line at the carburetor base is connected and no cracks in line.

blow into one end of the check valve and if air passes through then the end at your mouth will go to the distributor.

One line will go to the vacuum advance on the distributor and the other will go to the egr valve ...

You'll need to run ignition power to the new distributor. And you'll need to run a vacuum hose off the carb for the distributor vacuum advance. Really, very little of the original wiring will work. You'll need to connect the fuel pump to the vehicle fuel line.

Depending on your carb, distributor and transmission, you have from zero to two vacuum hoses. If you have an Autostick transmission, there's a vacuum hose running from a port in the intake manifold to the control valve on the left side wall of the engine bay. (Hint: if you've got a car that came with Autostick and that someone's converted to manual transmission, the bracket for the control valve is the perfect place for your coil.) Most people don't have this transmission even if their car came with it--it's only a three-speed and it's hard to find parts for it, so most of those cars have been converted to manual transmission. The other hose you might have is for your distributor. The port is on the left side of the carb, and a hose runs between it and the metal vacuum advance can on the side of the distributor. If you have a 009 distributor or an aftermarket distributor like an MSD you don't have the vacuum advance can; if you have an aftermarket carb like a Weber you don't have the port. Therefore...you probably don't have any vacuum lines on your engine.

if only one vacuum line then? the vacuum line goes from the vacuum advance on the side of the dizzy, to the carburettor, just around the throttle linkage if i recall. hope this helps.

You might have a small leak in your vacuum system, check all of the hoses and plugged vacuum connections. Check your plugs and wires, distributor cap and rotor. Sometimes a crack in the distributor cap will cause carbon to build up. Since carbon is an electrical conductor it might be jumping from one cylinder to another that is not in line with the firing order.

Get a tee fitting for the size of the vaccum line and connect the advanced line into an existing line from the carb. Worked for me on one of my old cars.

try checking these things out:
chec the wire connections at the distributor, coil, altenator
check your fuel pressure
check for vacuum leaks on all lines and at the throttle body and the intake manifold
also check your distributor cap to see if it has a crack in it