t100 project

I been chasing issue after issue on my son's 94 4 runner with v6, 5sp, 4wd. At first the 4wd didn't work. Someplace said a hose was disconnected and now it works. The problem is that I can't find any diagrams of how the lines come out of the vacuum reservoir that is in the right fender. I felt around on it and can only find one nipple coming off of it, but there are two hoses coming out of the right fender. One isn't connected (the left one) to anything, it just dead ends. Then the blue filter isn't connected on one end. Is there something that shows this hookup and/or routing. All the threads I look up don't have his exact setup as far as the vacuum hoses go. How can there be only one nipple on the vacuum reservoir?

scope103

Try this:

There is only one nipple on the reservoir, because it is a reservoir. Nothing goes "through" it; air is sucked out ("storing" vacuum), and the reservoir keeps vacuum on the line to the VSVs.

The blue side of the check valve connects to the vacuum "filter" screwed into the plenum, via a vacuum line labelled #*. Hey! That's the label on your unconnected mystery line coming out of the fender pass-through! If you pull that line off the pass-through you'll notice that the "nipple" is solid; no vacuum can go through it.

If you have cruise control, the #* line shares one of the nipples on the vacuum filter with the cruise control. What hook-ups do you have there?

You might want to inspect the check valve to see if it works. That could explain why someone was fooling around with the vacuum lines.

t100 project

The cruise is electric, works and has no nipple on it anywhere, nor that filter. I noticed that some other rigs had that on the pics they showed of their vacuum line setups. That's why I have so much trouble with the lines as I haven't seen one that looks just like this one.

Why would that line go in the fender and be capped? Wouldn't it have been easier for Toyota to just cap whatever it goes too? I'll have to go out and look, but I think it goes to one of the vss's.

https://www.yotatech.com/members/t10...131219-003.jpg

scope103

Here's a drawing of the vacuum "filter." Even though yours is a '95, I'm pretty sure you have one. (I think this drawing is for a 2wd, as it does not show the blue/white check valve. The check valve shown is orange/black and is for the PAIR.)

The line that goes to the "solid" nipple on the fender just isn't supposed to be there (Toyota, apparently, did not design that nipple to be used at all). You need a vacuum supply to your 4wd VSVs, and it should be labelled #*. The label isn't important, you just need vacuum through the check valve, and the place it's supposed to come from is the vacuum filter.

t100 project

I'll have to double check, but the line that goes in the fender is not on a nipple, it just is an unconnected line that is not plugged. It just goes into the grommet and is open on the end. I have the orange valve and its connected to the vacuum filter in your diagram.

The blue filter is unconnected on the blue end so there doesn't seem to be a source of vacuum for the reservoir, but the 4wd works. When my son gets home I'll have to get some more pictures. It just seems that there is a line or tee missing for the end of the blue filter to hook to. I've looked everywhere for an unused nipple, but can't find one.

t100 project

Here's the setup. The blue filter isn't hooked to anything and I think it was on the left nipple in fender that didn't go anywhere. What was this blue filter thing for? I can't find any unused nipple anywhere and where would the one going into the fender hook to? The other line in the fender comes from the the vacuum canister to the VSS.

rworegon

That should have another vacuum line attached to it. Look back at the parts diagram picture earlier in the thread.

t100 project

If you look at the bottom picture there is no line with a vacuum source except the vacuum reservoir (the lines t'd off the vss for 4wd come from the canister). The bottom hoses off the vss go down to the actuator on the front axle.

That diagram shows a vacuum source from the filter going to a double T that goes to the top of the vss and reservoir. I have no open nipples on the filter, so should I T into one of those lines with the blue filter and put a double T to the vss and reservoir? I just don't understand in that bottom picture where the reservoir or the vss for 4wd are getting a vacuum from.

scope103

This is what it should look like:

The "extra" nipple on the pass through, as I said, is not used. The check valve is connected to the Tee between the pass through and the two VSVs.

Your picture is hard to follow, but it looks like you HAVE the tee there. Where does it go to? I'm guessing that the line from the vacuum filter that is supposed to be connected to the blue-side of the check valve was disconnected and re-connected at the Tee. Bypassing the check valve. The good news is that whoever did this didn't throw the check valve away, but stuck the loose end of the white-side hose to the unused pass-through nipple just so it wouldn't flop around.

What does that do? It gives you vacuum to the reservoir and the VSVs, but that vacuum disappears with full-throttle. The reservoir is supposed to hold the vacuum when the engine is producing enough, but without the check valve the vacuum will just bleed away.

So, you pull the #* line off the Tee, connect it to the blue side of the check valve, and connect the white side of the check valve to the Tee.

Of course, somebody thought that didn't work. So you need to do ordinary diagnosis. With the engine running, is there vacuum on the #* line? With the check valve connected, is there vacuum through to the white side? And so on.

t100 project

Thanks, that's exactly what I needed. One last question. Never mind. I just figured it out. The line that comes off the T at the fender by passed the blue filter. Many thanks, this was exactly what I was looking for. I should have had a cup of coffee before I posted this.

KidSheleen

I know that I am waking up a very, very old thread, but your diagrams really, really helped me out. I had somebody replace the valve cover gaskets and the camshaft seals. When they put things together, they really screwed things up. CEL code 71 and no 4 WD. The vacuum sticker under the hood of my 1994 T100 does not show how the ADD vacuum is attached to the plenum air filter. Your diagram really helped. Now I have 4 WD. It will take a longer trip to see if the CEL 71 has gone away (hopefully). At least I can get 4 WD. My plenum air filter has all three ports unblocked, so I was able to attach the ADD vacuum line to one of the ports on the three port plenum air filter. Thanks, and I have saved your diagram to my computer (and printed it out).
Sorry again for waking up an old thread, but I need to give you the proper kudos.

Mark