Vac line attached to nothing

[GLet71]

I'm thinking this is the EGR, but correct me if I'm wrong. One line going in from exhaust manifold(?), and then a line coming out the bottom of the diaphragm into no man's land near the passenger wheel well. I can't seem to see where it goes according to the label on the underside of my hood.

[andrewrenow]

Yes I believe that's the egr valve. I dont know anything about vac lines but I know people have posted pics of the setup if that will help you out.

[ARCHINSTL]

There is a large diameter line at the bottom of the charcoal canister which disappears into the "frame member" on the passenger side.
There is also a tube from the diaphragm to the bottom of the EGR valve itself - look at pages EC-26 plus in the FSM.
Tom M.

[dlb]

glet, check this vacuum diagram. it's for canadian T4's so it should help you out with vac stuff. i printed it out large to have on hand while routing vacuum stuff, very useful. right click, save image, then print, i think.

https://tercel4wd.com/forums/viewtopic.php? ... 810#p55103

yes, that is the egr. it has several vac lines on it; one on the face of the saucer and two attached to the base. the saucer face line goes to a steel line a few inches toward the front of the car. of the two base-mounted lines, one goes to the port on the bottom of the egr vacuum modulator and the other goes to the MC valve which is mounted on the inner passenger fender. the MC valve looks kind of like an hour glass, if that helps.

as tom mentioned, the charcoal canister has a line out the bottom that sits in the frame but the charcoal canister should not be attached to the egr at all.

it's funny, looking at the vac diagram now, it doesn't show the vac lines attached to the egr base. maybe because they are the big fat ones, they don't count them. weird. anyway, they're there.

[GLet71]

Ahh, yes David, that is what I'm talking about. There is no indication of a line out either in the FSM or on the label located on the underside of my hood. That is why I have been so confused. I didn't, however, notice two lines coming out the bottom. I will have to take another look when I get the chance. If it is as you mention, I know where they are supposed to lead. If not, I will take some video to get a close up of the issue. Thanks for the help guys!

[GLet71]

Finally had a minute to work on the car today, and David had it right in that my line was meant to be connected to the MC valve. Funny, there was a professional looking red rubber cap over the nipple on the MC. Is there a reason why it would have been capped off like that? I removed the cap, and connected the egr line anyways. I then performed the MC valve test as stated in the FSM; vacuum works when disconnected (albeit only a slight tug), but it is difficult to tell if air is sucking through the bottom of the MC valve when I reconnect the vac line.

Bottom line question: Does this emission equation even matter?

[dlb]

someone probably disconnected that while testing something else and forgot to hook it back up, or they had a plug in the hose that fell out. i found the easiest way to test it connected is to pop it out of that clip and hold the bottom close to some exposed skin (arm, cheek, whatever) with one hand while i open and release the throttle with the other hand. when the throttle closes, you can feel it suck down. it actually attached itself to me last time. i was worried for a second.

this part of the system is definitely not a huge deal but so many of the emissions components are interconnected that i prefer to keep as many connected and functional as possible.

[GLet71]

Thanks David, I never thought to increase rpm's to increase vacuum. I'll have to check that one out!

[dlb]

yeah, i believe it only sucks a metered amount of air through the bottom of the valve on sudden deceleration so you have to open the throttle and then suddenly release it. should be a good hard suck (har har) for a second or two following the closing of the throttle.