Help With Vacuum Connections & Carburator

[Machman]

Hi Guys;

My car has a 302 & I was having a problem with the car stalling after deceleration,

If careful when first starting it I can get it to idle but the first time I press the pedal & increase the rpms (which is does fine) it will die when I take my foot off the pedal

I thought it was the dashpot as it was disassembled and in a box so I put it back together and installed & adjusted it on the carb but problem still persisted

I took the air cleaner off to have a look for vacuum leaks on hoses and saw lots of lines dissconnected?

Thank you in advance to all who reply

 

[RacerX]

That's the egress plate. A torn diaphragm wont cause a vacuum leak, it just wont pull the valve open when it should. Pull the Carb and plate and check underneath for rot eating thru it. They usually have rot thru the sides and leak after all these years.

 

[c9zx]

It sounds like it is an Exhaust Gas Recirculation (EGR) plate and valve to me. The diaphragm being torn will cause a vacuum leak if it is connected to an engine vacuum source. Is the whole engine from a newer vehicle?

 

[Machman]

Thank you for the reply

 

[Machman]

Hi Guys as I do not know if any of the vacuum lines are connected properly so below is a list of how things are connected.

Can anyone let me know if they are properly connected as I have no clue and am sure the motor will run fine once they are sorted out.

Vacuum connections on 302 Motor

Rear of manifold has 2 seperate NON electrical units screwed into it that have connectionss to attach vacuum hoses to

UNIT 1 has the ability to connect 4 vacuum lines to it

one connection is not connected to anything and blocked off with a stopper

one connection has a vacuum line that goes to the distributor

one connection has a vacuum line that goes to a pipe that goes below the firewall and under the car. (possibly to auto trans but I am not sure???)

Unit 2 has the ability to connect 2 vacuum lines to it

both connections were not connected to anything and left open to the air, I noticed this today and got a vacuum hose to connect them together so thery are not venting to the air or causing a leak.but I have no idea what would have originally gone to them.

Distributor has 2 vacuum lines going to it

one connection was mentioned above and connects to the 3 vacuum line unit bolted to the rear of the manifold

The other distributor vacuum connection goes to the side of the carburator

Any help on how to properly connect all this stuff up will be greatly appriciated

 

[c9zx]

71 302 should look similar to this. http://www.mustangbarn.com/images/vacs/71%20302%20and%20351W%20with%20(3)dvcv.gif

73 302 should look similar to this. http://www.mustangbarn.com/images/vacs/73%203-11A.jpg

If you could post picture we might be able to help more. Chuck

 

[Machman]

Thank you VERY much Chuck

 

[c9zx]

I can't help much but, I'll share what I THINK I know. The engine code tag (decal) on the front of the passenger's side valve cover is the late 1972 and newer format. If you can still read all the number it can probably be decoded to tell you exactly what engine you have. The valve in question is the EGR. The carb is 1970 or newer because it has a top mounted choke pull off. There may be a code on the carb base just aft of the front left mounting stud that could be used to ID the carb. The PVS is missing from the thermostat housing. I hope some of that was helpful. Chuck

 

[Machman]

I can't help much but, I'll share what I THINK I know. The engine code tag (decal) on the front of the passenger's side valve cover is the late 1972 and newer format. If you can still read all the number it can probably be decoded to tell you exactly what engine you have. The valve in question is the EGR. The carb is 1970 or newer because it has a top mounted choke pull off. There may be a code on the carb base just aft of the front left mounting stud that could be used to ID the carb. The PVS is missing from the thermostat housing. I hope some of that was helpful. Chuck

Hi Chuck; Thank you again for your help

 

[c9zx]

PVS=Ported Vacuum Switch. It is part of the vacuum advance control system and appears in the vacuum diagrams I posted earlier. One more piece of information, the carb appears to be late 72 or newer as it has a factory electrically heated choke. You could start looking for casting dates on various components ( block, heads, intake, distributor, etc). Chuck

 

[Machman]

PVS=Ported Vacuum Switch. It is part of the vacuum advance control system and appears in the vacuum diagrams I posted earlier. One more piece of information, the carb appears to be late 72 or newer as it has a factory electrically heated choke. You could start looking for casting dates on various components ( block, heads, intake, distributor, etc). Chuck

Thank you Chuck I will try to get some numbers on carb and manifold, which should be easy to locate

Where are the other numbers located aka Block, heads and Motor?

Can anyone looking at this thread post a quick picture of their 302 motor (w/ air cleaner off) showing the areas on front and rear where vacuum lines & connections are so I can get an idea of where things go (even if its a little different than my set up it might still help)

 

[c9zx]

Block:Remove the starter and look up. Should see a casting number (9 or 10 characters) and date code (3 or 4 characters). Should look similar to the attached picture in format.

Intake: On top of one runner, casting number and date code.

Heads: Remove valve cover. Casting date should be on the pushrod side of the rocker arm near the upper valve cover rail.