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Missing Vacuum Lines

Old Mar 24, 2021 | 10:28 AM
  #1  
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Stephen Comer
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Missing Vacuum Lines

2 days ago I purchased a truck for a father / daughter project. I'm excited for this forum and appreciate the years of experience and knowledge you all bring to the table.
1978 F150
351
Manual Transmission
4x4

The truck won't idle. Once it's up and running it's ok... not the best, but runs. Once you stop, it dies if you don't feather the gas. I'm starting with vacuum hoses that are missing. Can anyone connect the dots for me on these missing hoses? Or, if you can post a picture of your engine with the correct hoses, I can figure it out from there. Thank you!!!




 
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Old Mar 24, 2021 | 11:28 AM
  #2  
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#1 Not sure

#2 Opens/closes the flap in the air cleaner. When the truck is cold it’s shut and gets hot air from around the exhaust manifold. When it’s warm it opens and draws cool air in. I think it should be connected to the temp switch I talk about in #3.

#3 is a temperature activated switch. When the engine reaches temp, that switch should allow vacuum from manifold to open the EGR valve (#5).

#4 is a vacuum canister. I’m pretty sure it provided a “reserve of vacuum” if you will.

#5 Is the EGR valve. It circulates some exhaust into the intake to re-burn it for emissions reasons.
 
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Old Mar 24, 2021 | 01:40 PM
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Is the decal on the drivers side valve cover? if so that will give you the emissions calibration number. With that we can give you the vaccum diagram for your specific motor set up.
also https://www.ford-trucks.com/forums/9...am-needed.html
 
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Old Mar 24, 2021 | 04:19 PM
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Ya the vacuum lines are a mess. But it is really simple and nothin like the later trucks.

If you are not in a region that requires under hood or tailpipe inspections you can remove most of it. Let us know if you need to keep the emissions equipment or not.

Right off I can see that the Distributor vacuum line is not hooked up to the correct spot. (See below circled in red where the distributor should be hooked too) '

Start with that. And we can move on once we know if you have to keep the emissions stuff or it can go away.

Then we can get to diagnostics and tuning and sorting the rest of the mess out.



 
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