AMC Eagle Den Forum

The Mighty 258 => Emissions/Vacuum Systems => Topic started by: DaemonForce on May 04, 2013, 08:43:53 PM

Title: Another idenitfy this thingy
Post by: DaemonForce on May 04, 2013, 08:43:53 PM
Vacuum ball removed for this purpose.

What is the set of inlets that go underneath the vacuum ball and what are they for?

(http://img855.imageshack.us/img855/2133/dscf4391n.jpg)

I notice they seem to be some kind of ported vacuum with a delay when there's a drop in pressure. It's between the driver side fender and the frame so it's not like I can just get to it and see for myself. Any ideas?
Title: Re: Another idenitfy this thingy
Post by: BenM on May 04, 2013, 09:12:38 PM
I think that's the mysterious 4wd vacuum canister they hid in the fender.
Title: Re: Another idenitfy this thingy
Post by: DaemonForce on May 04, 2013, 11:00:16 PM
I do believe you may be on to something. It definitely has the properties of a vacuum cannister as you see in the picture I can just port my manifold vacuum to it without a cap and the engine runs perfectly fine. So lets see...I have a stealth 4WD vacuum, vacuum ball, vacuum cannister on the passenger side right above the cruise motor...How much reserve vacuum is the Eagle supposed to have and why do I need so many?! O_o
Title: Re: Another idenitfy this thingy
Post by: BenM on May 05, 2013, 07:21:19 PM
They wanted you to have plenty, I guess.

Chrysler hid one in the front bumper of the Cherokee. I know of at least one that was broken off its mount causing all sorts of problems for the engine and hvac.

They eliminated that one in later years and it shared with other items. You should see if it holds vacuum, or at the least cap off it's supply so you don't have a vacuum leak.
Title: Re: Another idenitfy this thingy
Post by: DaemonForce on May 05, 2013, 09:04:31 PM
This is very interesting because I use manifold vacuum on my 4WD reserve cannister and I just use the one right above that plumbing because it's convenient. They all work perfectly fine. I just thought it was a little weird that right under a vacuum ball is a stealth vacuum cannister. Apparently Chrysler wasn't the only company that went nuts with these things.
Title: Re: Another idenitfy this thingy
Post by: BenM on May 06, 2013, 10:28:24 AM
You ought to see a car with door locks and a trunk release powered by vacuum in addition to all the heater motors and emissions equipment.

I think the extra tank was added with stop-and-shift due to all the extra lines and second motor.
Title: Re: Another idenitfy this thingy
Post by: carnuck on May 06, 2013, 03:15:37 PM
Quote from: BenM on May 05, 2013, 07:21:19 PM
They wanted you to have plenty, I guess.

Chrysler hid one in the front bumper of the Cherokee. I know of at least one that was broken off its mount causing all sorts of problems for the engine and hvac.

They eliminated that one in later years and it shared with other items. You should see if it holds vacuum, or at the least cap off it's supply so you don't have a vacuum leak.

Actually, AMC stuck them in the right front corner of the bumper on XJs (Chrysler didn't take over till after the end of '87 model year and broke their contract by killing the Eagle line in '88 and selling the Eagle name after a lawsuit forced them too IIRC)

Even my '84-'86 XJs had the vacuum foot ball in the bumper and even the slightest love tap seemed to crush them and cause running issues. I moved mine under the hood and my Eagle wagon even has one under the battery box on the frame!
Title: Re: Another idenitfy this thingy
Post by: captspillane on May 10, 2013, 03:41:27 PM
The other side of that hole has two tubes that run up to a canister.

You need to plug one side if you have the other side still connected, otherwise it is just one big vacuum leak.
Title: Re: Another idenitfy this thingy
Post by: DaemonForce on May 10, 2013, 07:43:05 PM
Wherever that goes, it doesn't appear to be an issue even with the main manifold vacuum line hooked into it without a cap but it's not a problem anyway. That picture isn't an accurate representation as to how my Eagle's vacuum is setup. The thing I posted in the other thread gives you a better idea what it looks like because I don't have any delay valves, CTO, feedback systems or thermal switches. All of that is going to be scrapped in a few months anyway. I need to build a new 258 motor and at least I'll be dropping the entire vacuum diagram for more modern devices.