My original issue w/ mentioned in the following post:
https://www.ford-trucks.com/forums/1...arb-issue.html
(My 85 F-350 w/ 460 auto 2x4 hesitates (sound likes the engine is actually off for a split second) if you stomp on the gas. No backfiring.

I did not want to hijack that OP's thread, so I started this one. Went over all the vacuum lines and checked for any obvious leaks and found none. I followed and matched all my vac lines against the underhood decal:



Found (3) plugged lines, labelled 1,2 & 3.

1. comes off the "T" and is plugged. Not sure if this is to connect to my vac line on my air cleaner assembly. Right now it is, and has always been disconnected since I owned the truck

2. This line is also plugged. I believe the original factory carb was maybe a Carter and that line was connected then.

3. I found the end of this line plugged, but see that it is to be connected to the EGR, so I unplugged it and pit it on my EGR per the diagram. The truck ran no differently that I could tell.

Dropping my truck off tonight for a PA inspection tomorrow. The mechanic is good w/ carbs and is going to look at the accel pump as discussed in the thread mentioned above.

When truck is off and removed air cleaner assembly, I pulled the choke back and pulled the throttle cable. Only saw many drops of gas come out in both barrels, not a good stream. Made no sound either.

Could not find the tag to tell me what Holley model it is, but here is a picture w/ the following number: "80457-2" and under that is "2420"



Lastly, can someone tell me what are the (2) red arrows pointing to? The top one is plugged. The bottom arrow, well, I never seen something like that connected to the intake manifold the way it is. There are two holes where this is connected.




Thanks, as I am hoping the mechanic can fix this hesitation issue once and for all.

PS. Better shot of the Carb / Setup

 

Ok, quick and dirty.

#1 does indeed attach to the air cleaner bi-metallic switch (round device on the air cleaner with 2 ports to the outside)

#2 goes to the throttle "kicker", which should be located on the carb, right in front of the throttle linkage (don't see one in the pictures)

#3 does hook to the EGR valve, but the valve only operates under certain engine load parameters (determined by the vacuum signal, and engine temp).

Most '85 460's came with a Holley carb from the factory, but the only way to be certain if this is original, is if we know the specific "calibration code" from the engine. Seeing as the valve covers look to have a fresh paint job on them, I doubt you would be able to find it, as it was usually on a sticker on one of them. Also, I would hazard a guess it's not, since it has a vacuum port in the metering body where I'm assuming the distributor is hooked?

The line off the "top" of the carb (plugged) is probably the "E" port, which, according to your diagram, is where the EGR system should be hooked.

The copper line, I'm guessing, is a hot air feed line for your choke pull-off. Don't remember seeing many of them on 460's, but I haven't seen them all.

 

That is not the original 4180 carb, it is a 4160 that someone had to retro fit to make it work. Too bad, I could have walked you through the correct hookup just by memory. The hesitation is most likely the acc. pump diaphram, an easy and cheap fix.

 

Thanks for the replies guys. Sorry, I should had said the original carb was replaced w/ this one about 10 yrs ago.

And yes, those were salvage yard 460 valve covers, I have the original grey ones somewhere i the basement. I know it still has the sticker.

Here is the pic where I attached the one vac line circled in red. Before, it was not attached and the line was plugged off.



Atleast my vac line diagram is not as crazy as some I have seen. Truly hoping the accel pump is the issue and can be fixed. Also kind of pissed that the replacement carb was not replaced w/ the original model

 

No problem. Some people like the 4160's better, being easier to tune, but it can play havoc with trying to make the emissions work properly, since they are not original.

 

Gotcha, I hope the vac line I hooked to the EGR will be ok. If not I'll just remove it and plug the end like it was. When I connected it back up, I started the engine and let it idle for about 10 minutes. The engined seemed to run no differently than when it was not connected.

PS. I also looked up a Holley 4180 and saw the "kicker" you were referencing.

 

It's easy to make sure the EGR has the signal it needs. Start the engine from sitting overnight(cold) get under there and pull the rubber line off the EGR valve. Hold your finger over the hose, there should be no suction. Rev the engine some, there still should be no suction on the line when the engine rpms are up.

Take the truck down the road and get it warmed up fully. Leave it running, open the hood, and at a idle, take the EGR hose off again. There should be no suction. Then rev the engine, there should be suction when it's warmed up and you rev the engine.

 

Thank you for that info. I will try that out. Does that mean if it works as you described, does the suction at higher rpms after being fully warmed up, cause the EGR to open or close? I guess the next thing to do after I follow your instructions is to make sure the EGR itself is good. For almost 10 years, I have not had that vac line connected to the EGR (Circled in red) and the other connection that was not there was the other live going to the air cleaner assembly.

 

The suction when warmed up and at high RPMs opens the EGR valve by overcoming a spring tension, allowing some exhaust gas to be fed back into the intake. This is supposed to happen only at higher RPMs on a warm engine.

Considering that, another easy way to "field test" whether the EGR valve is working is to open it slightly when your engine is at idle. If you reach around to the back side of the EGR valve (careful, watch out for the fan blades, etc.), you can gently press on the valve with a finger to overcome the spring that keeps it closed. If you do this, your engine should sputter and possibly even stall out. This verifies that the valve is closed at idle (as it should be) and does properly feed exhaust gas into the intake.

 

The EGR is only supposed to work when 2 conditions are met.

The first is that it's getting vacuum. Manifold vacuum specifically. Manifold vacuum is at it's highest when you're idling or maintaining speed. When you punch the throttle, the throttle-valve in the base plate opens and the vacuum inside the motor is offset by the atmospheric pressure. That is, manifold vacuum (below the TV) drops and ported vacuum (above the TV) starts to come in.

The second condition (on other motors, your diagram looks like it shows different) is when the ported vacuum switch that sits on top of the heater hose fitting opens up. The way this works, as the motor heats up, the coolant heats too. And, as the coolant heats, there's a bi-metallic spring inside of the PVS that acts just like the spring on an electric choke. As it warms up, it opens. This allows vacuum to flow through the PVS.

So, the EGR only works when you've got high manifold vacuum (cruising, idle) and when the motor is warmed up (coolant), and it shuts off when your step on the loud pedal to go fast (lack of manifold vacuum to hold the diaphragm open).

So you can see why the stories that people tell you about disconnecting the EGR on a stock engine are BS. An EGR doesn't take anything away from power, and only increases the MPG's of the motor by using exhaust gases to take up space in the cylinder (gas and fresh air can't flow in when the space is already taken ). Disconnecting the EGR on a stock motor can also result in pinging or ignition knocking as the distributors are specifically curved to run with an EGR, as the EGR lowers combustion chamber temperatures.

Disconnecting the EGR on a modified motor is a different story.

The main reason an EGR was put on a vehicle is to pull carbon monoxide and nitrous oxides into the motor to be re-burnt. The catalytic converter (your truck probably didn't come with one) helps convert the carbon monoxide, nitrous oxides, and other emissions to water and carbon dioxides.

Believe me, there is plenty of disinformation regarding emissions equipment. Like the commonly held belief that the smog pumps rob power from a motor. That's another hoax...

 

I appreciate the detailed explanation. I was hoping to get everything as close as possible back to the way it was. Everything is pretty much stock on that truck, motor-wise, except the Holley Carb (4160). I did not realize those items were even disconnected (EGR and Air Cleaner Assembly. As always I appreciate the knowledge of passing along 'correct' information. And yes, my truck did not come from the factory w/ CATS.

 

I can't remember the actual GVWR number that meant the vehicle didn't have to have cats, but if I remember right, it was around 8500 lbs GVWR. Someone somewhere will verify this.

 

Yes correct and, my PA registration is also higher because that is my GVWR on the door jamb

 

The EGR DOES NOT work at idle. The vacuum line is not hooked to manifold vacuum, it's hooked to a ported vacuum source that only has vacuum when the throttle is opened some. If the EGR worked at idle, the engine would stall out and not run.

Also something that has not been brought up yet since we are getting into the little in's and out's of the EGR. Most Ford EGR's of this era also work off of exhaust backpressure. If you take a line and run it from a vacuum port on the intake(has vacuum all the time) and hook it to the EGR, and expect the EGR to open and the engine to stall, it probably won't. There is a metal plate inside the EGR that exhaust back pressure pushes on. If this plate is not being pushed, some of the vacuum from the EGR signal port is bled away to a felt filter around the outside edge of the EGR. As the rpm's increase, this plate covers the "leak" more and more, letting the valve open more and more. This keeps the EGR system from having a "on" "off" type of operation, and makes it more gradual, the higher the rpm of the engine, the more EGR it can stand.

So if you try to suck on the EGR and make it open, and it doesn't and you think it's bad, it's probably not(been there, done that).

Of course if you modify the exhaust to a free flowing type, you will have less back pressure, and that throws the whole thing off. That's why the exhaust system is considered part of the emissions of the engine, it's more than just a catalytic converter.