AMC Eagle Den Forum

The Mighty 258 => Emissions/Vacuum Systems => Topic started by: DaemonForce on May 04, 2013, 11:10:45 PM

Title: What all is wrong with this?
Post by: DaemonForce on May 04, 2013, 11:10:45 PM
Besides my PCV inlet mocking me as an outlet, what is functionally WRONG with this diagram?

(http://img32.imageshack.us/img32/2200/83mod1.png)
Title: Re: What all is wrong with this?
Post by: BenM on May 05, 2013, 07:53:22 PM
There should be two lines going to where the "???" is. The top one goes through a delay valve and a thermal switch to the emissions port on the carb, the capped one. It should only have vacuum with a warm engine after a slight delay when that port opens; the emissions port is a ported vacuum source.

The top port on the canister should hold vacuum, it opens a port and it has a rubber diaphragm that sometimes goes bad. Just that part is available if it doesn't hold vacuum.

The bottom port goes to the capped T for the brake booster or tees into the PCV line. It should only flow when the top valve is open. The line has a restricter in it, usually pressed into the canister opening.

You can use the same feed for the canister to run your EGR valve, splitting it after the delay valve, but I like to use two different valves so they don't come in at the same time.

You also need manifold vacuum and a storage tank for the heater controls.
Title: Re: What all is wrong with this?
Post by: DaemonForce on May 05, 2013, 09:00:41 PM
These are some very good points. Thing is, I don't have a THERMAC, so there are no switches. I'm also having issue with a dead spot in acceleration caused by my aftermarket air cleaner(I'm not kidding). There has never been a CTO installed and I always found that to be a little weird. I'm not sure how to plumb the EGR without one either. Should I just splice it with ported vacuum on the carb and the ??? on the charcoal cannister? :-\
Title: Re: What all is wrong with this?
Post by: BenM on May 06, 2013, 11:10:08 AM
Prior to the aluminum intake AMC mounted them into the water jacket in the block. There are two plugs on the driver's side that will take a CTO valve.

I would try to put a CTO on. The simple two/three port switches are about $20, or I bet someone here has a few laying around. It's supposed to open around 160. Just bypass the CTO for now, it's a cold driveability item. You may find you don't need delay valves either.

The emissions port is on the front of the carb at the base on the left as you face forward. (So it's on the right as you're looking at it standing in front of the car.) It's designed for controlling the EGR and canister. Start by just hooking them to that and see if you get any surging when you ease off the throttle as you reach cruising speed.

If they're working properly, they only function at light throttle/light load and turn off as soon as you hit the gas or lift off.

I've always been a fan of stock air cleaners, but I drive all winter. I've seen guys cut out the hole in the bottom and just rivet and caulk the bottom of an aftermarket air cleaner to it to get the hole size right. It works for a long time.

Oh, and I was reminded writing this, use a purple/black delay valve. (http://en.wikipedia.org/wiki/Vacuum_delay_valve) on the distributor. AMC seems to have them listed on everything, I think to deal with sudden throttle closure causing the timing to advance. It should say "dist" on the side that goes to the distributor, and there were many variations of it.
Title: Re: What all is wrong with this?
Post by: carnuck on May 06, 2013, 03:10:22 PM
The motors with a factory tin valvecover had the one piece intake/exhaust (siamesed together with bolts under the carb) and the CTO was on the block below.