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I know there are tons of questions on these, still sure what I am looking at.
Initially didn't see this unconnected port on the tree. I've found what I think is the correct diagram. Should this be the routing, and what does the end connection say/mean? Hope y'all in the northeast enjoy the storm, and/or make it through OK.
Thanks in advance, OB
Ok on the real picture are you pointing to the hose going to the base of the carb or the nipple on the vacuum tree?
I think the vac tree, but the drawing does not show the "open" port on the tree right?
You should not have and open vacuum ports! All should be sealed/capped.
Now your truck may have say 6 ports on the vac tree but may only use 3 ports. The other 3 ports would be sealed/capped.
Now did you put the blue arrows on the drawing? If so what are you trying to say?
I see it starting at a vacuum source/vacuum tree. The vac line goes to a "T" the black thing and then going to 2 valves.
I cant read what the 2 valves feed EGR? and Air ???? ?
Dave ----
Hey Fuzzface, thanks for the quick reply. i'm trying to see where that exposed nipple in the photo routes too. I Think the blue arrows point to where this line should start and end, but can't read the label/acronym on the schematic. That's why I put ??? next to it. Hopefully someone has a better resolution version or knows from experience. I couldn't find another open vacuum port anywhere else that looked lonely lol.
It runs OK with this open, and quite well when I capped it,(almost 12mpg around our rural area). I want to see if I can get it running better, especially before things heat up this summer.
Well if you don't see any hoses that might have fallen off cap it off.
As for if that open port should go to something you will need to do a little home work.
Before you start your home work remember what I said of "your tree may have 6 ports but you may only need to use 3 so 3 are not used...read capped.
Did you say you still have the hose routing sticker under the hood?
If so go by that for your truck as they do change from truck to truck.
This link may help also 300 Six - ???Gary's Garagemahal
as it has some routing stickers.
Dave ----
edit: Looking over the drawing it lists a "throttle body" (TB) but your picture shows a carb.
I see TB and think EFI (Electronic fuel Injection) so that drawing may not be the best to go by fro your carbed truck as some of the things listed may not be used on a carb motor.
Osagebow, as you know, your 1984 4.9L is computer controlled with regard to carburetor and timing. If something is amiss, the computer will lock the timing @ static [10 BTDC] and put the carburetor in its richest mode, so gas mileage will suffer as well as overall performance. It looks to me that the choke's hot air tube is not connected to the exhaust manifold. Is that correct?
By the way, when checking on the port with the missing cap, look in line with it and closer to the engine there may likely be another port. It should have a rubber cap which after all these years, may be missing or cracked. Ask me how I know?
I agree - if there is no errant hose then cap the fitting off. As Dave said, not all ports were connected. Ford seems to have used vacuum trees that had enough ports for the worst case, and capped those not used.
Ok I bet I knocked a cap off when I reconnected that thin metal line with the cloth insulation to the manifold (JB weld as per someone old thread). The large manifold intake shroud is gone, so there is nothing to connect the 2" wide or so line next to the air intake.
1986F150six- I have a good mech I'll have him check the timing. She'll do 65 at 2600 rpm with the low 4 speed granny.
Thank you guys - fixin' to play in the snow. we have two dead trees leaning over down the road, hoping this wet snow takes one or both down and I get some free wood.
The line that goes from the manifold tree with the blue arrow, goes over on the red line to two vacuum reservoirs. Or a reservoir with two parts to it. I am not familiar with something like that to serve the egr solenoid and the "Air" whatever it is. That would have to be the smog pump wouldn't it?
Here's a 84 4.9 diagram that I found. Seems to be more reasonable than yours, this one has the air cleaner lines on it, and has 3 solenoid valves. How many valves does yours have on it?
Thanks for the info guys. Capped 2 unused lines on that tree, another was hiding under there. Truck ran noticeably smoother, but at a higher idle, about 1200 when hot. Should I walk that down a bit?
Can't see the pic there Franklin, but am I looking for a vacuum reservoir? Another post used that as a synonym. If so, I think only 1, this guy: yep, that top line broke as soon as I looked at it wrong.
I don't have the coffee can i see discussed in many 4.9 threads
Last edited by Osagebow; Mar 13, 2017 at 09:42 PM.
Reason: Pic
Yes, you should get the idle down to about 600 or so. And the thing in the pic is the vapor canister. It stores gas fumes from the tank and carb until the engine starts, and then they get sucked in and burned.
Your sticker is the same diagram I tried to post. That diagram looks a lot better. You might want to get a piece of paper and draw the sticker out to make it nicer to see and work with, and to save it. Stuff like that is what you are going to have to do if you are serious about keeping this thing running.
Here's a link to that diagram I posted. See if it will work by clicking on it. The place I got it from may not allow the forum software to go get it. It may not allow you guys to go in directly either, but try it.
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