I recently acquired a $300 1978 F-100 Ranger XLT with the 400 ci engine (a/c, cruise control). Due to massive fouling of the fuel system I have had to remove,clean and/or rebuild the tank,lines fuel pump and carb(2150) most of the vacuum lines were gone when I got the truck and now I am down to getting everything hooked up again.


I have some questions

1) all the lines going to and from the evaporative cannister are rotted out and unusable will it hurt to just plug the tank vent line and the carb bowl vent?

2) there is a large silver colored diaphram type device that is hooked into the intake below the carb in the rear of the engine it is sticking out over the oil pressure sender the line to it has been plugged.
What is it and where do I hook it to?

3)on the choke heater there is a line going down to the exhaust crossover then back out to a line that has a vacuum hose on it but It is not connected anywhere.
Where does that hook ?

4) on the pass front lower part of the carb is a plugged vacuum line What is it supposed to hook to?

5) there is a vacuum connection thing that sits almost on top of the thermostat what is it and where to hook it it has two connection points?

6)for now at least where is the distributor vacuum advance supposed to hook up to?


I have a vacuum diagram that is supposed to be this truck but it has a lot of stuff that is not on the truck and isn't very clear on the connections around the carb.


BTW I have really been trying to read as much as possible on this site and have learned much just by reading dag nabbed vacuum lines just kicking my hiney tho

 

Vacuum Advance line goes to a ported spot on the bottom of the carb

Click the photo of my truck and then scroll to the bottom of the page.
You will see a link to Vacuum diagrams.

Dennis

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the links on your page just lead me to autozone error messages......

What is a ported vacuum connection is that the lower pass side front one

 

Yes it is !
Ported Vacuum is a term used for Vacuum appearing when the engine demands it(Like, at the bottom right hand port of carburetor)

Full Vacuum(non-Ported) would be from the intake manifold.
(Like at the back where the Brake booster & Transmission vacuum line hooks up)


I'll check the link.

Meanwhile try this one.

http://www1.autozone.com/servlet/UiBroker?ForwardPage=/az/repair_info/repair_guide/repair_guide.jsp


Dennis

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When you get to the broken kink error message just hit the submit button. The links have been moved. Go to the vehicle repair info, then to your model, and into the emissions controls. There is a huge LONG list of vacuum diagrams. There is a whole lot of other info there so the long route could be educational.

Or you can follow this new link direct:
[link:www1.autozone.com/servlet/UiBroker?ForwardPage=az/cds/en_us/0900823d/80/0c/e6/05/0900823d800ce605.jsp|Vacuum diagrams]

There are a lot of other components in your vacuum system that operate the EGR etc that you may have to get from the Junkyard.

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[updated:LAST EDITED ON 01-Jan-03 AT 07:57 PM (EST)]I can tell you what little I know. I went to the link on autozone, and it's good they have the diagrams, but it would be nice to know what the abbreviations stand for, and what their purpose is.

1) all the lines going to and from the evaporative cannister are rotted out and unusable will it hurt to just plug the tank vent line and the carb bowl vent?

......you can't plug the vent to the fuel tank. The cap is non-vented, and air has to be allowed into the tank when fuel is taken out by the fuel pump. I also wouldn't plug the vent on the carb. In my experience, it makes it hard to start in hot summer weather.

2) there is a large silver colored diaphram type device that is hooked into the intake below the carb in the rear of the engine it is sticking out over the oil pressure sender the line to it has been plugged.
What is it and where do I hook it to?

.......this is the egr valve. It should be hooked up to avoid pinging with an original carb. Problem is how? Looking at the diagrams, there must be 10 different ways. Mine on my 351w is hooked like this: The line comes from the egr valve, and has a little check valve looking thing in the line. I don't know if this is the "vres" thing or not. It then goes to a thermal vacuum switch mounted in the intake manifold coolant passage. This blocks egr operation till the engine warms up. From the temp switch, the line then goes to the ported vacuum source on the front driver's side of the carb.

3)on the choke heater there is a line going down to the exhaust crossover then back out to a line that has a vacuum hose on it but It is not connected anywhere.
Where does that hook ?

........mine's not like that, but the ones I've seen hook the line back up to the carb. This spot on the carb just has a hole leading to the top of the carb inlet. This is a controlled vacuum leak, and they want the air sucked in to be clean. The air flows through the line, gets heated by the exhaust, then flows into the choke housing where it warms the choke coil.

4) on the pass front lower part of the carb is a plugged vacuum line What is it supposed to hook to?

.....I have one pointing toward the fender in that location(side of the carb). It goes to the distributor. I have a large one in the front lower middle of the carb. It goes to the canister and the PCV valve. The one on the front drivers side goes to the egr system.

5) there is a vacuum connection thing that sits almost on top of the thermostat what is it and where to hook it it has two connection points?

......I think this is the thermal vacuum switch for the egr.

6)for now at least where is the distributor vacuum advance supposed to hook up to?

...... Mine hooks to the passenger side vacuum port(has the long nipple).


This emissions stuff still grips me. The government has all these regulations to force car makers and owners to put all this emission stuff on their engines, but offer no help or resources to figure out what's going on and how to keep the systems working. Then they wonder why everybody takes all this stuff off all the time.

 

Thanks for the good info again franklin2!

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I have the abbreviation definitions if anyone wants them.

Dennis

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Dennis, I would like them. I looked in some of my factory manuals and could not find them. Maybe we can start figuring some of this stuff out ourselves.

 

Haynes sells an "Emissions" book. It cover general material, but it does have the abbreviations and definitions. The book helped me finally get my canister plumbed correctly...as well as SMOG my 300 from scratch.

 

Thank you for this very informitive post. between this and the diagrams I have and whats on autozone I believe I may be able to get most of this stuff hooked up. I prolly will have to get even more hose but I think I can do this now. Be trained as a US Navy steam plant mechanic I can work on and understand most anything mechanical and electrical stuff comes pretty easy. Usually with references available It is pretty easy to work on cars if I have the correct tools on hand but vacuum circuits kick my hiney even if I have the origina diagrams that are supposed to come with the auto.

And why is it that the vacuum diagrams are never exactly specific to the auto I am working on.

 

It gets more involved.

Can you say " Calibration Code " ?

Now everybody usually " snickers when I post this kind of stuff" but, Your calibration code number is 8-62J-RO
That's the diagram you need.


Dennis

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[updated:LAST EDITED ON 02-Jan-03 AT 06:01 PM (EST)]Many thanks to those who helped me figure out the vacuum hoses. My truck now runs. A little history here, A former co-worker has had this truck sittin in his yard not running for about 9-12 months. I finally asked about the truck and he offered to sell it to me for $300. It is a 1978 F100 Ranger XLT with loads of options, Now in my lifetime I have owned 4 trucks all fords (of course) and all from 71-75 and never had one that refused to run. In fact I never had to do more than routine maintenance. I have spent the last 2 weeks fighting this truck trying to get it running finally I gave up and just started at the tank and worked my way all the way to the carb cleaning the fuel system including acid cleaning the tank new fuel pump and now 3 fuel filters (the oem filter, a inline on the pump suction and a inline at the tank) during this cleaning I found two complete blockages in the fuel line and removed over a half-buckets worth of trash from the fuel lines and tank. with a little help from you guys here I finally got the vacuum lines hooked, primed the carb and turned the key to hear a sweet noise of combustion even better it kept running when I let go of the key. Now all I have to do is fixed all the minor electrical problems and tighten all the loose bolts ...(front bumper is barely bolted on) then I can ride in true style.


WOOO HAAAA I just took her out for a spin..........she still needs a little tweaking but WOW has she got some low end torque sounds like I got something loose on the front of the engine so I got go through all that stuff and see what all the noise is about at first I thought it was the valves but now I dont think so. running about 15-20 psi oil pressure at cruising speed it looks like so I think I am ok there but the transmission is not shifting very smooth doesnt want to hit fourth (auto) acts like it is trying to stay in passing gear and it will go ahead and shift if i let all the way off the pedal and drop to idle..........so I reckon I will just check the books and probably check out the modulator also.........