I hate to have this be my first post, but I desperately need this truck running. (needs smog in CA so I can register it)

I've had the truck for years, just sitting in my yard. I finally decided it's time to get it back on the road after all these years, and realized it didn't have any of the smog parts.

I went and bought a smog pump, egr, and a few other parts and pieces.

The truck has a bunch of vacuum hoses plugged/capped, and I have no idea what goes where anymore. There is no more diagram under my hood, and the valve cover sticker is long gone.

I don't necessarily need an exact map, but something similar would be of much help. Tell me what you need from me, so I can help you help me. =p

I've been searching for weeks for a diagram, and checked out/bought a couple books. I haven't been able to find a factory service manual for my truck as of yet, but am still looking.

Any help is very much appreciated.

 

Welcome to FTE. The EGR valve connects to ported vacuum through a ported vacuum switch in the thermostat housing (or nearby). There is a connection for ported vacuum on the front of the carburetor underneath the fuel bowl near the driver side idle mixture screw; there is also one under the choke housing on the passenger side. Vacuum goes from here to the ported vacuum switch, it doesn't matter which port in the switch. The other port on the switch goes to the EGR valve. If this truck hasn't ran in years, you probably need to replace the switch as well as they often fail closed and rarely stand the test of time.

The smog pump is belt driven; it's only vacuum connection is the bypass valve which prevents air from entering the exhaust stream on decelleration. There is only one port on this valve and it connects directly to manifold vacuum.

Other common vacuum connections. If you have power brakes, manifold vacuum connects to the booster. Manifold vacuum runs to the PCV valve. Manifold vacuum also runs to the heater controls and often a vacuum reservoir (through a check valve) which looks like a coffee can under the hood. The warm-air bypass system on the air cleaner sources manifold vacuum as well. Lastly, you'll have a vacuum advance on the distributor that runs to ported vacuum which I expalined above.

Lastly, if this is a truck that has to pass smog and it has sat for several years, you will surely want to rebuild the carburetor.

 

Thank you for that. It should help quite a bit. I'll give it a shot. If anyone has a diagram for a visual reference I would appreciate it.

 

Take a look at the quick diagram I made, I hope it helps you. It is a fairly common setup. The only thing I left off was the warm-air bypass for the air cleaner. Also I have the PCV valve going underneath the carburetor, that is because many EGR spacer plates include a 3/8" manifold vacuum port for the PCV valve but you can get it anywhere that sources manifold vacuum.

 

You are my hero.

I'll give it a shot and let you know how it goes.