AMC Eagle Den Forum

The Shop => Under the Hood & HVAC => Topic started by: SpectreMkVIII on December 16, 2024, 04:14:01 PM

Title: Redo Vacuum Lines From Scratch?
Post by: SpectreMkVIII on December 16, 2024, 04:14:01 PM
Hi all, long time reader and first time poster. I have a bit of an interesting situation. A few years ago I bought a 1984 Limited Wagon as a project and I've been doing work on it every so often. The previous owner seems to have removed every single piece of vacuum equipment from this thing, from the lines to the evap canister to the EGR valve. They also replaced the Carter BBL with a Holley 2300. I've been trying to buy new bits and pieces when I can find them so I have a small collection of random bits and pieces along with what was put in a box and left in the back. How should I start putting everything back together? I have the TSMs, I have the Chilton's guide, but whenever I consult the diagrams I have no real idea what should go where, or what I should even do first. Any help would be appreciated.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: 89 MJ on December 16, 2024, 05:28:17 PM
What part of the vacuum system do you want to start with? 4wd, engine stuff, etc?
Title: Re: Redo Vacuum Lines From Scratch?
Post by: Ludworks on December 16, 2024, 05:35:33 PM
Hi Spectre, welcome to the forum.

So the vacuum system on an Eagle is best looked at in chunks. There's a separate system for EGR, Evap, 4wd, heater controls, etc. They overlap quite a bit, but tracing out the lines that are specific to whatever system you're trying to rebuild can help you ignore the clutter.

How familiar are you with the stuff you want to work on? I recommend you do some research on the general mechanisms of EGR and Evap before you try and tackle them. Understanding how a vapor canister is supposed to work is more important than exactly replicating what the factory did.

You'll need to have all of the various bits and pieces of each system before assembling. The EGR valve, the EGR CTO, and the EGR TVS will all need to be in hand and in good working order before you run any EGR lines. From there you can either try and replicate the factory location for each component or, for components that don't need to be directly bolted to the engine, locate a good location on the firewall or fender and temporarily attach them there. Next route vacuum lines from one component to the next following the diagram. It should quickly become obvious if you need to move any components. Once the lines are attached try running the engine and see how it responds. If all is well you can consider attaching things permanently.

Build each system out separately as much as possible. Vacuum tubing is cheap so buy a roll of whatever sizes you need and don't be afraid to cut and redo lines as necessary. As long as you don't lay anything on the exhaust manifold you'll probably be just fine. The factory routing is not always the best, so don't be afraid to deviate and switch things up.

Oh and be aware that the diagrams differ depending on year, state, etc. Probably best if you pick the simplest one and start there. I'd recommend starting with the Evap system. It's probably the easiest to get your head around and you really can't hurt too much. Make sure you get a correct fuel tank cap if yours has been changed out though.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: rmick on December 16, 2024, 10:22:40 PM
Eaglepedia has the diagrams broke down in sections. Pick one and start from there. http://amceaglesden.com/guide/Diagram_Section
Title: Re: Redo Vacuum Lines From Scratch?
Post by: SpectreMkVIII on December 17, 2024, 12:13:10 PM
Hi all, thanks for the responses. I suppose I should start with identifying what I have so I know what I can do with it all. When I first tried taking a crack at this stuff last year I bought an EGR Valve and an Evap Can along with a few rolls of different sized line. Ideally I'd like to have the essentials up and working, stuff like the brake booster and the 4WD actuator but I'm trying to start with the EGR system since it's a small loop. However, I don't believe I have the TVS. I took a few photos of what is in the car at present that I didn't throw in myself, the only think I can somewhat positively identify is the CTO. I'm not sure what the second port on the intake manifold is, nor what the doohickey that was loose in the back is. Also, what's the significance of the fuel filler cap?
Title: Re: Redo Vacuum Lines From Scratch?
Post by: Ludworks on December 17, 2024, 01:06:26 PM
The parts catalog should be a great help in identifying what you have: https://amceaglesden.com/guide/1984_-_1988_Factory_Parts_Catalog

Based on your first post I thought you meant the car was running and driving, in which case I thought that the PO may have replaced the non-vented gas cap with a vented one, since they junked the entire Evap system. However it doesn't sound like that's the case here.

Considering your situation, have you thought about doing a 4.0 head swap or an aftermarket TBI system?

Title: Re: Redo Vacuum Lines From Scratch?
Post by: SpectreMkVIII on December 17, 2024, 01:42:48 PM
The car was in fact running and driving when I got it, my dad drove it home. I blew the clutch while I was learning to drive manual and it sat for a bit until I replaced it. I think the PO mentioned doing the head swap before I bought the car as well. The issues at the time were the reverse lights not working (fixed when I had to drop the transmission for the clutch plate change) and the 4WD system not working, which is probably due to the fact that there is no vacuum system anymore. I'm also worried about the brake booster since I'm led to believe that that also relies on vacuum to function.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: 89 MJ on December 17, 2024, 01:47:55 PM
You are correct, both the power brakes and the 4wd are vacuum operated. The brake booster has a large rubber hose going from the intake manifold to the passenger side of the booster, next to the master cylinder. If that is there, your power brakes should be working (unless your booster is bad, but let's assume its working fine for now)
Title: Re: Redo Vacuum Lines From Scratch?
Post by: SpectreMkVIII on December 17, 2024, 02:02:59 PM
I'm assuming this is the hose you're talking about, it ends in a junction block just below the carburetor. However, the other end of the junction block is capped off. Should that connect to anything, or is it fine? I can't seem to find anything about it in the diagrams or the TSM.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: 89 MJ on December 17, 2024, 03:09:26 PM
Quote from: SpectreMkVIII on December 17, 2024, 02:02:59 PM
I'm assuming this is the hose you're talking about, it ends in a junction block just below the carburetor. However, the other end of the junction block is capped off. Should that connect to anything, or is it fine? I can't seem to find anything about it in the diagrams or the TSM.

I believe that piece goes into the intake manifold and that's where the vacuum comes from. I think having the other end capped is fine for now.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: SpectreMkVIII on December 17, 2024, 04:30:58 PM
Alright cool, less work for me. The plan currently then is to cut a hole in my air cleaner to fit a TVS since it doesn't have one in it and connect that loop up. I'll spend some time thinking about what I can do for the 4WD system.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: MIPS on December 18, 2024, 02:59:11 PM
So going from your first set of photos, the black two-port fitting in the manifold jacket is the ECR CTO. I believe starting in 1983 they got rid of the dual-action CTO valve which did cold spark delay (I believe it was integrated into the computer along with electronic spark retard?) and the EGR and you got that much more simplified valve. The TVS should be the blue plastic thingamajig on the back of the air cleaner with two ports. Seeing how you don't have the original air cleaner you neither have the TVS AND I've yet to find the cross-referencing Ford part (it is a Ford part originally.
In a pinch you can drive without the TVS, however the EGR will then operate unnecessarily when it's cold outside.

The single post brass fitting at the back of the manifold is your Early Fuel Evaporation switch. There's a relay in the engine bay somewhere that would be turned on/off with this and turned the heating element under the carburetor on/off.

The brass fitting at the front of the manifold with the wires clipped off flush was the coolant temperature switch for the computer. Those at least you can still buy over the counter at AutoZone.

The brake booster has only one place on the engine it will go and as you can see that's in the correct place.

I made a video a number of years back that's somewhat of a crash course on the vacuum routing and visually shows where most of the lines should go. It's different before and after 1982 but a lot of the components are still there.

https://youtu.be/hen6KRTwric

Redoing the 4WD and AC vacuum lines, those are the fun ones. SelectDrive used rigid plastic lines with rubber end fittings. The fittings are mostly Ford parts but the lines you'll have to be creative because they were thin and small so they routed easily. Same with the A/C vacuum lines which I'm guessing PO didn't pull the controls out of the dash to delete the lines and you will find three small hoses running the the blend controls that are clipped and pushed under the dash. Both also need vacuum canisters (and check valves?) which would of been bolted to the firewall or down by the brake proportioning valve.

Edited:
A vented gas cap won't cause EVAP performance or vacuum issues but you'll get that gas smell on hot days. A new sealed cap is $15 anyways so if you are going to fix the EVAP system it doesn't hurt to replace the gas cap.
Watch out for the check valve hiding in the fuel return hose up by the carburetor! Once the EVAP is pressurizing the tank again if that check valve is missing the carb will chronically flood. There's also a pinhole restrictor in the port running to the charcoal canister from the fuel tank vapor line. PO may of already tossed the hose with it stuck in there.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: Ludworks on December 18, 2024, 05:24:50 PM
MIPS, I didn't know that was your video! Awesome job man. You explained everything really well.

Spectre, what's your goal for the car? Are you trying to take it back to stock?
Title: Re: Redo Vacuum Lines From Scratch?
Post by: SpectreMkVIII on December 18, 2024, 08:03:38 PM
Thanks for the video link MIPS, I'll watch it soon! The current update is pretty simple, I cut a hole in my air cleaner and threw in the TVS I pulled out of a Jeep air cleaner (My other project car is a '56 CJ-5, I got a '75 CJ for parts) and got the EGR loop hooked up. It'd be kind of neat to get it back to being a fully stock system but with the amount of parts I'm missing I don't think it's feasible. The current priority is going to be getting 4WD operational and to figure out to to fix the vacuum advance since that had a line connected to the CTO for some reason (my guess is that I was not paying attention to the routing diagrams when I first started this whole ordeal). The diagram under the hood wants it to be connected to some unlabelled mystery port and the vacuum switch assembly which has been deleted by the PO.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: MIPS on December 19, 2024, 11:14:24 AM
Quote from: SpectreMkVIII on December 18, 2024, 08:03:38 PM
and to figure out to to fix the vacuum advance since that had a line connected to the CTO for some reason (my guess is that I was not paying attention to the routing diagrams when I first started this whole ordeal)

I can answer that (and it's in the video as well for reference)
Hot or cold, the earlier Eagles used a dual-mode CTO (the plumbing is independent from the EGR vacuum but both valves share the same port on the manifold coolant channel) to add or remove a delay pod in the vacuum routing to the advance canister. Never tried with it completely removed (later CeC's don't use it) but I know (and it's written on this forum somewhere) that if you get it plumbed backwards you get a cold engine that's very prone to stalling out on acceleration and a hot engine that's more likely to knock.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: vangremlin on December 19, 2024, 07:08:46 PM
You can also lock it into 4WD without the vacuum system being operational.  Let us know if you're interested and we can walk you through it.  Good luck!
Title: Re: Redo Vacuum Lines From Scratch?
Post by: SpectreMkVIII on December 19, 2024, 08:32:00 PM
Permanent 4WD does sound like the simpler and more practical option, I would be interested in giving it a shot. What does it entail? Anything special?
Title: Re: Redo Vacuum Lines From Scratch?
Post by: MIPS on December 20, 2024, 12:14:58 AM
I find with mine there's the additional driveline noise but also against the numbers that running with/without 4WD full-time doesn't notably affect MPG the engine needs a bit more throttle to accelerate.

Eagles with the front axle disconnect have a bit more vacuum routing than later models with just the actuator at the transfer case. Vacuum is ONLY needed to shift in/out and doesn't need to be present to keep it engaged/disengaged.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: vangremlin on December 20, 2024, 11:30:20 AM
Quote from: SpectreMkVIII on December 19, 2024, 08:32:00 PM
Permanent 4WD does sound like the simpler and more practical option, I would be interested in giving it a shot. What does it entail? Anything special?

Shifting the transfer case is easy, you just use a 9/16 or 5/8 wrench (I can't remember which) and using the shift lever on the case move it forward into 4WD.  You can use some bailing wiring or zip ties to hold it there so it doesn't slip into false neutral. 

For the front axle, you can go the more permanent route and open up the little case on the passenger side axle and slip a hose clamp over the shaft inside to hold it engaged.  Here is a how to:

https://amceaglesden.com/guide/Front_Axle_Lock

Or I think you could run a vacuum hose directly to just to the front axle shifter and I think that should lock the front axle so it's 4WD capable.

Sorry if I'm not very good with the terminology and I may not be totally correct on some minor details but those are the basics.  If I have any wrong Den members, please help me out!

Good luck!
Title: Re: Redo Vacuum Lines From Scratch?
Post by: SpectreMkVIII on December 20, 2024, 05:12:43 PM
I read through the axle lock process, seems simple enough. Unfortunately it will have to wait since I just got some snow up where I am so I'll have to wait for it to settle down a bit before I decide to slide under the car and bash my knuckles against cold metal. That leaves the distributor advance, which no longer has a home. Thoughts?
Title: Re: Redo Vacuum Lines From Scratch?
Post by: 89 MJ on December 20, 2024, 06:08:13 PM
Quote from: SpectreMkVIII on December 20, 2024, 05:12:43 PM
I read through the axle lock process, seems simple enough. Unfortunately it will have to wait since I just got some snow up where I am so I'll have to wait for it to settle down a bit before I decide to slide under the car and bash my knuckles against cold metal. That leaves the distributor advance, which no longer has a home. Thoughts?
That will have to be plugged in on the carburetor somewhere above the throttle blades. Anywhere below the throttle blades will not have vacuum at WOT.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: SpectreMkVIII on December 20, 2024, 06:34:20 PM
Got it, I'll see what I can find. My 2300 doesn't seem to have that many vacuum ports on it
Title: Re: Redo Vacuum Lines From Scratch?
Post by: SpectreMkVIII on December 20, 2024, 07:44:19 PM
So, PO put a Holley 2300 on this thing, list number R1929-S. This thing came off of a 50-60s Ford V8 and has a grand total of 2 vacuum ports on it, the lower one connected to the PCV and the other is what I connected to the EGR loop. Should I tee off the EGR line and hook in the advance to it?
Title: Re: Redo Vacuum Lines From Scratch?
Post by: 89 MJ on December 20, 2024, 07:50:31 PM
I'm thinking that I would move the EGR vacuum port to the intake manifold (actually I'd get rid of the EGR, but you might want or need to keep the EGR) and plug the vacuum advance vacuum line to the spot on the carb.
Title: Re: Redo Vacuum Lines From Scratch?
Post by: SpectreMkVIII on December 20, 2024, 08:00:26 PM
And undo all of my hard (not at all) work so far? Kidding, of course. I can do without the EGR stuff, I'm sure it'll be fine.Thanks everyone for the help so far!