Strong vacuum line not connected, where's it go?
Thread Starter
|
Tuned
Joined: Aug 2004
Posts: 311
Likes: 4
From: Omaha, NE
Strong vacuum line not connected, where's it go?
Have a 87 4.9l with EFI, under the hood there is a vacuum line about 3/4" or so with a very strong pull. Feels like a shop vac. It looks as if it is supposed to be plugged into the air box since there is a hole about the same size that was plugged (it was just rammed in the opening of the box when I bought it). Hose has a redish plastic tip/inset on the end, perhaps where it went into the box.
Also have a larger hose, about the size of a radiator hose with very little, if any pull.
Both worry me greatly, little one because of such a strong pull, and the big one for its size.
I have the Chilton's (1987 E-150), but the vacuum diagram is for the carb version and I know very little so it's still not a whole lot of help.
I know it's vague, but any info is appreciated. Thanks.
Also have a larger hose, about the size of a radiator hose with very little, if any pull.
Both worry me greatly, little one because of such a strong pull, and the big one for its size.
I have the Chilton's (1987 E-150), but the vacuum diagram is for the carb version and I know very little so it's still not a whole lot of help.
I know it's vague, but any info is appreciated. Thanks.
Postmaster
Joined: May 2002
Posts: 3,241
Likes: 3
From: Broken Arrow, OK
The one by the airbox goes into the airbox and should have a small foam filter on it that's about 1.5"x3". It has vacuum because it is the crankcase vent that feeds the PCV system.
Where's the larger hose at?
Where's the larger hose at?
Thread Starter
|
Tuned
Joined: Aug 2004
Posts: 311
Likes: 4
From: Omaha, NE
Line with the foam filter is a different one, that's on the back side of the airbox, this string one looks like it might go on the front. Unless there are supposed to be two little filters, and the one was discarded when they plugged the hole?
Not quite sure where the big one goes. It is hanging around by the radiator and the airbox, damn vans. I think it snakes down to a metal pipe (almost copper in color) near the intake manifold, but the metal pipe isn't hooked up to anything. Haven't been down to mess with it in a few days, will check and get back to you. There is a smaller pipe that looks near identical, except it has a smaller diameter, and that one is hooked up.
Sorry for the vague descriptions and uncertainty. Will double check everything. Hard to tell what is EFI, and what was the propane stuff that was installed (for a novice).
Not quite sure where the big one goes. It is hanging around by the radiator and the airbox, damn vans. I think it snakes down to a metal pipe (almost copper in color) near the intake manifold, but the metal pipe isn't hooked up to anything. Haven't been down to mess with it in a few days, will check and get back to you. There is a smaller pipe that looks near identical, except it has a smaller diameter, and that one is hooked up.
Sorry for the vague descriptions and uncertainty. Will double check everything. Hard to tell what is EFI, and what was the propane stuff that was installed (for a novice).
Laughing Gas
Joined: Dec 2005
Posts: 904
Likes: 115
From: Laurel, MS
Hard to say without seeing it, but what you're describing sounds an aweful lot like the AIR tube the goes to the rear catalytic converter.... not really sure where they're mounted on a van though... opposite side on my '91 pickup. As for the small vacuum line, the air tube has a switch on it that is vacuum controlled... maybe it's supposed to go there.
Posting Guru
Joined: Dec 2004
Posts: 1,159
Likes: 0
From: Connecticut
Thread
Thread Starter
Forum
Replies
Last Post
xjcamaro89
2004 - 2008 F150
463
Feb 13, 2026 05:07 AM
mudinford
Modular V8 (4.6L, 5.4L)
38
Dec 26, 2015 12:02 PM
tommythomasson
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
7
Nov 21, 2007 07:37 PM
