How many capped vacuum plug on your vacuum manifold

[vq5speed]

I did a bunch of work on my X this weekend. Changed my Rocker Arms and pushrods. Changed my exhause manifold gaskets. Switched out Evap core and Condenser. Added Auxiliary tranny cooler with fan. I put everyting back together only to find I have one of my vacuum ports left unused on the manifold. I searched everywhere cannot find what is not hooked up. Ones accounted for vacuum to my brake booster, fuel valve,kickdown cable,transmission. 2 on my air cleaner box,one on that A/C capsule thingy that controls the air duct flaps. What else is there. The vacuum under the throttle body is hooked up what am I missing? I always had 2 capped on that manifold. Since I cannot find what is missing I just capped it for now. the motor seems to run fine can't figure out what vacuum is not hooked up.

 

[Bobmbx]

If you're lucky, there's a vacuum hose map on the cowling near the hood latch. If not, you can google for your specific year/engine.

 

[coco944x4s]

Cruise control?

 

[vq5speed]

Where is that located exactly Is that a big round thing near the drivers fender..

 

[Maniak]

Where is that located exactlym Is that a big round thing near the drivers fender..

The vacuum canister with a cable coming out of it on the driver side fender.

also, I don't think I've ever seen an explorer (1st gen) that didn't have at least 2 of those ports just capped off.

~Mark

 

[vq5speed]

ok that's hooked up the cruise control..

What I have kinda mixed up is that 3 way T on the drivers side a small line is coming out of a wire harness down by the Code connector. It goes into the T where one line goes into that A/C capsule shaped thing. The the other line goes to the vacuum manifold? The 2 that go into the Airbox one line drops down below the battery somewhere. The other one where does it come from?. Then the fuel valve that line goes right to the vacuum manifold right?

 

[Maniak]

I found this old post that may help.. it's a little old though (only 14 years )

http://www.explorerforum.com/forums/showpost.php?p=75818&postcount=8

There is 1 that goes "to" the airbox and then one that goes from the airbox down under the battery to the thermactor valve. That is what pre-heats the air into the engine when it is really cold (take hot air from around the exhaust manifold)

Also, that thread/link above is for a 1992. You will also have one for the heater control bypass valve (the one you called the a/c capsule). At least I'm thinking that is what you are talking about BUT the 1991 didn't come with a heater control bypass valve but someone could add it.. If so, the vacuum line for that should be coming from inside the vehicle. I can't think of anything else that you would consider an a/c capsule.

So, for your 1991, make sure the following things have vacuum lines, which port they go to doesn't really matter.. Some might even T into a single line at the octopus.

• FPR
• Brake Booster
• cruise control
• transmission (goes to a metal line that runs down to the automatic trans)
• vacuum canister (small cylinder thing by the heater-a/c box) - Is this what you meant by the a/c capsule?
• Thermactor valve (that isn't the right name, but it is the fitting "on" the air box)

Any other ports on the vacuum octopus/tree should be capped off.

There is also a vacuum line on the bottom of the throttle body but that does NOT get vacuum from the octopus. That one runs to the evap purge solenoid which goes to the charcoal canister.

 

[vq5speed]

The one going "to" the air box is coming from where?

 

[Maniak]

The one going "to" the air box is coming from where?

Eventually, it comes from the octopus BUT I think that is one of the ones that has a T in the line so a single line may be feeding that and something else.

The reason I'm not positive is I have replace all my lines with new rubber lines AND all that mattered was that I got vacuum to each pieces, so that is what I did.. I don't think I have any T's in my lines, each one is a home run to the octopus.

~Mark

 

[vq5speed]

Sorry for my chicken scratch writing..

 

[Maniak]

The line going into the harness (on the left of the drawings) should be going into the truck to run the blend door. In your drawing there is no vacuum source to that circuit. That source should be on the vacuum tree/octopus.

So, you need something in between your 2 drawings.. According to your drawings you are missing a vacuum source..

Don't spend too much time trying to get it to look "stock", just make sure each things gets a vacuum source. You are already almost there.

Using drawing 2 as your guide, You just need to get a vacuum source to that circuit you have on the left of drawing 2 WITHOUT disconnecting anything else. You could just add another T to do that so you can get that left circuit connected to the tree without leaving the airbox connection open.

~Mark

 

[vq5speed]

Took your advice and hooked new lines up so each thing gets its own vacuum source. I may of had something not hooked up before I worked on it. I'm thinking I never had a vacuum line going to my fuel valve before I took it apart.Any ways here is a new picture of what I have it now. The a/c capsule thing only has 1 vacuum nipple no elec plug or any other nipple coming out. So what does it do?? some kind of vacuum reservoir?

This is what I call the Capsule. It only has one nipple for vacuum what does it do??

 

[Maniak]

Took your advice and hooked new lines up so each thing gets its own vacuum source. I may of had something not hooked up before I worked on it. I'm thinking I never had a vacuum line going to my fuel valve before I took it apart.Any ways here is a new picture of what I have it now. The a/c capsule thing only has 1 vacuum nipple no elec plug or any other nipple coming out. So what does it do?? some kind of vacuum reservoir?

<snipped pic>

This is what I call the Capsule. It only has one nipple for vacuum what does it do??

So, close, but you have the idea..

The capsule thing (as you call it) is a vacuum reservoir. It doesn't "do" anything other than hold vacuum.

This is where you need to make a change. The vacuum reservoir is used to help keep vacuum available for use by the blend door. That is the door in the dash that moves with the a/c controls.

So, What you need to do is take the vacuum line that runs to inside the vehicle (it appears to be the top on in the pic I snipped out, running into a wire harness) and connect it to the capped T you have @ the canister (capsule).

Once you do that cap off the open port you just made at the vacuum tree.

That should be the last thing you have to modify to get everything working..

BTW, if you really didn't have vacuum running to your FPR you have been running with higher fuel pressure. That means you gas mileage "may" go up a little now that you have vacuum going to the FPR.

Oh yea.. Just so you know, since you have a 1991 you have what looks like a MAP (manifold absolute pressure) sensor. It is actually a BAP sensor.. You can see it in the pic I snipped. It is on the firewall, has an electrical connector and what looks like a vacuum port on it with some white plastic around it. That white plastic is supposed to make it so you don't hook anything to it. It is using it to know the barometric pressure to help figure out the mixture. I'm just letting you know since I've seen some with that plastic broken off and then someone hooked a vacuum hose to it thinking it was supposed to have it.

~Mark

 

[vq5speed]

Ok did one more change I decided that line going into the harness to keep it "T'd" with the capsule thingy. I don't know what that a/c capsule does but I think it needs to be "T" with the line going into the harness. So now I only have 1 capped vacuum source on the tree now everything else has its own vacuum source. So there is nothing else missing is there?

 

[Maniak]

I think you understand it now.. You fixed it by doing what I said to do, before you saw my post..

Yes, cap off any open ports on the vacuum tree now that everything is connected, you won't use them all.

~Mark

 

[vq5speed]

Yeah I think I was always missing the vac going to the fuel valve. I notice that valve when I tearing it apart and remember saying to myself oh crap I didn't know that was tucked down there and saw no vacuum was attached. So that's what gave me a open nipple cause I rehooked it up putting it back together.

 

[vq5speed]

BTW, if you really didn't have vacuum running to your FPR you have been running with higher fuel pressure. That means you gas mileage "may" go up a little now that you have vacuum going to the FPR.

Oh yea.. Just so you know, since you have a 1991 you have what looks like a MAP (manifold absolute pressure) sensor. It is actually a BAP sensor.. You can see it in the pic I snipped. It is on the firewall, has an electrical connector and what looks like a vacuum port on it with some white plastic around it. That white plastic is supposed to make it so you don't hook anything to it. It is using it to know the barometric pressure to help figure out the mixture. I'm just letting you know since I've seen some with that plastic broken off and then someone hooked a vacuum hose to it thinking it was supposed to have it.

~Mark

I hope my gas mileage gets better now lol..

Are you talking about this thing is a BAP sensor

 

[Maniak]

I hope my gas mileage gets better now lol..

Are you talking about this thing is a BAP sensor
<image snipped>

Yup, That's it.

~Mark