What am I missing here?
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Posting Guru
Joined: Sep 2009
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From: Suburbs of Chicago
What am I missing here?
Hey all,
I'm fairly certain I have a vacuum leak, and I was getting around to replacing all the lines when I noticed this on the passenger side rear of the engine:
It looks like something is definitely missing from that port marked "A". I'm not sure what exactly the line goes to.
I know I am also missing the heater control box, does that have any vacuum lines running to it that this could go to?
Stalling every time I hit the brakes is getting old so I'd like to figure this out ASAFP.
I'm fairly certain I have a vacuum leak, and I was getting around to replacing all the lines when I noticed this on the passenger side rear of the engine:
It looks like something is definitely missing from that port marked "A". I'm not sure what exactly the line goes to.
I know I am also missing the heater control box, does that have any vacuum lines running to it that this could go to?
Stalling every time I hit the brakes is getting old so I'd like to figure this out ASAFP.
Fleet Owner
Joined: Dec 2009
Posts: 20,678
Likes: 83
From: NorCal
Mikeo0o0o0... Help me Obi-Wan.....
What is the purpose of the plug on the firewall? I have the same unconnected plug on my rig and haven't been able to understand its purpose. I've reviewed the wiring diagram with no success. My rig is a 73 F100 4x4 w/o AC.... thanks in advance.
What is the purpose of the plug on the firewall? I have the same unconnected plug on my rig and haven't been able to understand its purpose. I've reviewed the wiring diagram with no success. My rig is a 73 F100 4x4 w/o AC.... thanks in advance.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Based on its location, the two-connector pigtail is most likely the hot-in-RUN signal for the idle stop solenoid, and the stator signal for the electric choke assist. It's hard to make out the colors to be sure.
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Mikeo0o0o0... Help me Obi-Wan.....
What is the purpose of the plug on the firewall? I have the same unconnected plug on my rig and haven't been able to understand its purpose. I've reviewed the wiring diagram with no success. My rig is a 73 F100 4x4 w/o AC.... thanks in advance.
What is the purpose of the plug on the firewall? I have the same unconnected plug on my rig and haven't been able to understand its purpose. I've reviewed the wiring diagram with no success. My rig is a 73 F100 4x4 w/o AC.... thanks in advance.
I don't think its the idle stop solenoid as fmc400 suggested though. Mine has one and that wire uses a single bullet connector, plus its on the drivers side of the engine.
I'll do some research and let you know if I come up with anything.
Here's a picture of the firewall, you can see there isn't any plug in my harness.
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Mikeo0o0o0... Help me Obi-Wan.....
What is the purpose of the plug on the firewall? I have the same unconnected plug on my rig and haven't been able to understand its purpose. I've reviewed the wiring diagram with no success. My rig is a 73 F100 4x4 w/o AC.... thanks in advance.
What is the purpose of the plug on the firewall? I have the same unconnected plug on my rig and haven't been able to understand its purpose. I've reviewed the wiring diagram with no success. My rig is a 73 F100 4x4 w/o AC.... thanks in advance.
The reason I ask about the change is because on '73's the wiring for the automatic choke is entirely within the alternator wiring harness. After looking at my '75 I think fmc400 IS correct. One of the two wires in the plug is white with a black trace. This is the wiring color code for the automatic choke. On my '75 the choke is disconnected and there is no sign of the wire that hooks to the choke housing so logically, it used to plug into that unused plug.
The other wire is light blue with no trace. I don't know what this goes to but at least you're half way there.
Fleet Owner
Joined: Dec 2009
Posts: 20,678
Likes: 83
From: NorCal
FMC400 and Mikeo0o0o0... You guys rock. I appreciate your taking the time to help me out.
YES, my cab is from a 73 2WD on a 74/75 4x4 frame...more like a 74 cuz I haven't found any PN codes later than D4xx.
YES, my cab is from a 73 2WD on a 74/75 4x4 frame...more like a 74 cuz I haven't found any PN codes later than D4xx.
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Posting Guru
Joined: Sep 2009
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From: Suburbs of Chicago
Are you sure? Not trying to be a pain in the ***, but according to this thread it could either be a vacuum delay valve, something to the tank, go to the carb spacer, something for the emission vacuum control, or God knows what.
There is no vacuum line running to my load control valve on my carb, either. Is it from this?
There is no vacuum line running to my load control valve on my carb, either. Is it from this?
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Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Are you sure? Not trying to be a pain in the ***, but according to this thread it could either be a vacuum delay valve, something to the tank, go to the carb spacer, something for the emission vacuum control, or God knows what.
There is no vacuum line running to my load control valve on my carb, either. Is it from this?
There is no vacuum line running to my load control valve on my carb, either. Is it from this?
In the link you provided, look at the second illustration (green). Item #11 is the part you are questioning. I know its hard to read but in the parts list that accompanies the drawing it shows item #11 as vacuum amplifier, biased.
Again, hard to see, but there are only two lines going to that side of the amplifier.
I am going to see if I can find a clearer diagram for you, if I'm lucky a full vacuum hose diagram.
I'll let you know if I come up with something.
Here's an illustration from the Ford Master Parts Catalog, its not all that clear either but you can see that there are only two lines to the vacuum amplifier. I'd like to come up with the vacuum diagram specific to your truck.
Click on the .pdf link to view.
Last edited by mikeo0o0o0; Sep 24, 2010 at 08:46 PM. Reason: additional info
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Here's a little more info. The part in question is Ford basic p/n 9E451, Amplifier assy. (exhaust gas recirculation vacuum).
Check this old thread, look in particular at the #5 post. In the illustration the port in question is listed as "vent".
https://www.ford-trucks.com/forums/6...-question.html
Check this old thread, look in particular at the #5 post. In the illustration the port in question is listed as "vent".
https://www.ford-trucks.com/forums/6...-question.html
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Mikeo0o0o0... Help me Obi-Wan.....
What is the purpose of the plug on the firewall? I have the same unconnected plug on my rig and haven't been able to understand its purpose. I've reviewed the wiring diagram with no success. My rig is a 73 F100 4x4 w/o AC.... thanks in advance.
What is the purpose of the plug on the firewall? I have the same unconnected plug on my rig and haven't been able to understand its purpose. I've reviewed the wiring diagram with no success. My rig is a 73 F100 4x4 w/o AC.... thanks in advance.
. The plug is for the automatic choke (white wire w/ black trace) and carburetor throttle emissions solenoid (blue wire w/ no trace). Found a wiring diagram that had the plug (C-406).
Thread Starter
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Posting Guru
Joined: Sep 2009
Posts: 1,159
Likes: 1
From: Suburbs of Chicago
You're not being a pain in the ***. You have something you don't understand and are asking for help, no problem.
In the link you provided, look at the second illustration (green). Item #11 is the part you are questioning. I know its hard to read but in the parts list that accompanies the drawing it shows item #11 as vacuum amplifier, biased.
Again, hard to see, but there are only two lines going to that side of the amplifier.
I am going to see if I can find a clearer diagram for you, if I'm lucky a full vacuum hose diagram.
I'll let you know if I come up with something.
Here's an illustration from the Ford Master Parts Catalog, its not all that clear either but you can see that there are only two lines to the vacuum amplifier. I'd like to come up with the vacuum diagram specific to your truck.
Click on the .pdf link to view.
In the link you provided, look at the second illustration (green). Item #11 is the part you are questioning. I know its hard to read but in the parts list that accompanies the drawing it shows item #11 as vacuum amplifier, biased.
Again, hard to see, but there are only two lines going to that side of the amplifier.
I am going to see if I can find a clearer diagram for you, if I'm lucky a full vacuum hose diagram.
I'll let you know if I come up with something.
Here's an illustration from the Ford Master Parts Catalog, its not all that clear either but you can see that there are only two lines to the vacuum amplifier. I'd like to come up with the vacuum diagram specific to your truck.
Click on the .pdf link to view.