There are several diagrams around here, or there were for a while. I rebuilt my whole emission control system, for an 87, so yours should be identical. I deviate just a bit from factory fresh, but in an attempt to make it easier.
Start by looking at the front of the carb:
1. On the left-hand side about halfway up is the ported vacuum nipple.
2. On the right-hand side, on the base, is the EGR nipple. This is originally capped. It is a second, slightly different ported vacuum source.
On the back, looking from the front of the car:
3. PCV vent nipple, it is larger then the others.
4. Pull-off nipple. This only goes to your vacuum pull-off on the carb. Don't attach anything else here.
5. Accessory nipple, full manifold under the carb. This is for your air-cleaner.
On the intake manifold itself:
6. At the very back, one or more nipples screwed in. These are for vacuum-powered accessories like Cruise, 4wd, heater valve.
7. Large nipple on the side below the carb for the Brake Booster.
8. Small nipple below the carb for the full manifold emissions system parts.
Port #1 (ported) goes across the engine to the 10/4 switches. It should go to the "natural" colored one. There is no delay valve in the line, but a reverse delay valve (White/Color) will delay the MCU from retarding timing at idle a few seconds. If your engine stalls coming to a stop or parking, this will help. I have a White/Gold (15 second) valve there.
The line splits and also routes through the plastic thermostatic switch in the side of the air cleaner and goes to the top port on the canister. This purges the vapors when the air cleaner is warm. It is not necessary to also use the CTO switch, as the PCV valve offsets any air bleed from the canister. A forward (Black/Color) delay valve in this line is possible, but not necessary. It connects to the top stacked port on the canister.
Port #2 (EGR) I route this down to the single CTO switch, center port. Plug the EGR into the open hot port (outside, I believe). Use a forward delay valve (Black/Color) here to delay EGR activation a few seconds on acceleration. Orange, Purple, or Gray are good choices, in increasing order.
Port #3 (PCV) This port goes to your PCV valve, and has a "T" in it for one of the ports on the evap canister. Usually the bottom of the two stacked ports on one side. If this port on the canister flows when all other ports are disconnected, the evap canister is bad.
Port #5 (Air cleaner) This port goes to a "Y" or "T" and supplies the two doors on the air cleaner. One side goes through a delay valve or a check valve and opens the back vacuum motor when the engine runs. The delay valve should be the longest reverse delay you have on hand, but a check valve will work too.
The other side of the split goes through the thermostatic valve on the bottom of the air cleaner and to the front motor on the snorkel to switch between the stove and cold air. There is no valve on this line, the thermostatic switch is calibrated for the whole works.
Port #6 (ACC) Route all your accessories through here. Check valves and tanks as appropriate.
Port #8 (Emissions) This line goes across the engine to a "Y" or "T" split by the 10/2 switches. It goes to the green colored switch and the distributor. The switch side goes through a small vacuum canister about the size of a film canister then a purple/black delay valve. The other side goes straight to your distributer.
The purple/black valve is the generic distributer delay valve available for almost any car. It is a 4 second forward delay valve that keeps the advance from coming in right away. Jeeps from 74-80 used a red and blue delay valve on EGR, which you can order. Blue side goes to the valve and the red side goes to the CTO.
The purple/black valve can be added in before the distributer if you get detonation when you lift the accelerator suddenly.
I hope this helps.
Topic: Emmissions Question (Read 22743 times)