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There is a vacuum canister to the right of that line that just sits inside the fender. Hard to see but there is a nipple that hose attaches to. That canister is a vital part of engine performance.
There is a vacuum canister to the right of that line that just sits inside the fender. Hard to see but there is a nipple that hose attaches to. That canister is a vital part of engine performance.
Hmm, seems to be running OK, what should I be looking for, what happens if that is disconnected?
Do you have a picture of the thing, I could not see in there because the view is blocked by the fuse box, and I couldn’t feel anything when I felt around. Where do I look?
I just took a picture of mine, the nipple sits immediately behind that big bolt. You should be able to feel it with your finger.
I'll make a correction on that canister being vital for engine performance, more like that vacuum canister is a needed vacuum supply to operate your inside climate control, (floor, defrost, vents selectors) it also is used to run the 4WD vacuum system.
I believe the canister is more for the HVAC operation more than it is for engine performance. Don't get wrong, a giant vacuum leak like that could certainly cause engine running issues lol, but completely bypassing that vacuum canister would not change the running of the engine at all.
That canister holds vacuum for the HVAC system so that when you pull out into traffic and have to get onto the throttle and vacuum drops in the intake of the engine, the HVAC control systems still have vacuum for a little while and don't loose their function, since all the actuators (minus the defrost one I think, it's an electric actuator) are vacuum controlled. The 3-way split those lines are connected to has a built in one-way valve so that when vacuum goes away in the intake, the valve snaps shut and holds vacuum in the canister and the HVAC system.
For a short time I drove around my fathers 94 Sonoma. He had bypassed the canister for the same reason, rotting lines, instead of just replacing the lines. Everything functioned like it should, engine ran great and heat and AC both worked. But under long periods of acceleration and with the heat or AC blowing out of the vents, the actuators in the dash for the HVAC system would loose vacuum and flip out. Basically the air would stop blowing from the vents and switch off. Drove me nuts...
I just took a picture of mine, the nipple sits immediately behind that big bolt. You should be able to feel it with your finger.
I'll make a correction on that canister being vital for engine performance, more like that vacuum canister is a needed vacuum supply to operate your inside climate control, (floor, defrost, vents selectors) it also is used to run the 4WD vacuum system.
Thanks I got it fixed now. The end of the old tube actually rotten off on the nipple so I had to try and prey it off with my finger nail, I eventually got enough of it that I was able to get the new one on. The new one was about an inch too short though, I measured the new one from the old one without realizing that the end was still on the nipple; I managed to make it work though, but the new one is stretched tight and just barely on the T junction, but it seems to be holding. I couldn’t hear or feel any vacuum leaks. While I was messing with it though that big tube at the top snapped off, the end of that one was dry rotted as well. There was enough play in it though to reattach the unbroken piece. So it’s a good thing I noticed this.
08-31-2019 | 03:51 PM
Mystery vacuum line
I got it fixed now. The end of the old tube actually rotten off on the nipple so I had to try and prey it off with my finger nail, I eventually got enough of it that I was able to get the new one on. The new one was about an inch too short though, I measured the new one from the old one without realizing that the end was still on the nipple; I managed to make it work though, but the new one is stretched tight and just barely on the T junction, but it seems to be holding. I couldn’t hear or feel any vacuum leaks. While I was messing with it though that big tube at the top snapped off, the end of that one was dry rotted as well. There was enough play in it though to reattach the unbroken piece. So it’s a good thing I noticed this.
