New Bronco New Problems - 1975 Bronco

[Bronco_007]

(Oldtimer beat me too it)

That's a lot of vacuum leaks...

You have an EGR spacer, the EGR valve (and a transducer depending on year) bolts onto it. The outside holes are bolt holes, the inner two are in/out. You'll need a block off plate or EGR valve to cover it.

The nipple on the back of the carburetor is for PCV valve. Original carb would not have that nipple as PCV goes into the front, so cap it.

The vacuum tree is for everything else.
1. Larger nipple is for brake booster
2. Others would be EGR, transmission modulator, exhaust valve, port vacuum switches, etc...

Your carburetor is a Motorcraft 2150 (not Holley). It's missing the lever that activates the spring valve on the top late for the EVAP nipple on the top plate.

All good info. But my carb says Holley…. Does that change your assessment? Appreciate any and all advice!

 

[Bronco_007]

(Oldtimer beat me too it)

That's a lot of vacuum leaks...

You have an EGR spacer, the EGR valve (and a transducer depending on year) bolts onto it. The outside holes are bolt holes, the inner two are in/out. You'll need a block off plate or EGR valve to cover it.

The nipple on the back of the carburetor is for PCV valve. Original carb would not have that nipple as PCV goes into the front, so cap it.

The vacuum tree is for everything else.
1. Larger nipple is for brake booster
2. Others would be EGR, transmission modulator, exhaust valve, port vacuum switches, etc...

Your carburetor is a Motorcraft 2150 (not Holley). It's missing the lever that activates the spring valve on the top late for the EVAP nipple on the top plate.

So A is for my brake booster and B should be plugged? Or should B go to manifold vacuum? Which I will have to look for…

 

[Bronco_007]

Th

Carb spacer plate for EGR valve.
The valve has been removed and it appears plugs have been used to seal two center ports.
Spacer plate also has vacuum port on front edge.
I think I see somthing connected to it in one of your photos

These are vacuum ports?

 

[Bronco_007]

Indeed, it is. You can either connect it with a hose if you want (best case), or for the time being cap it off, so nothing unwanted gets into the carburetor through it.

Looking for

Indeed, it is. You can either connect it with a hose if you want (best case), or for the time being cap it off, so nothing unwanted gets into the carburetor through it.

I’m looking for the bowl vent on mine… still looking…

 

[tirewater]

All good info. But my carb says Holley…. Does that change your assessment? Appreciate any and all advice!

Lol, too many different carbs in this thread. Yes, that's a Holley 2300 variant. The picture I thought being referenced was the carb with the evap vent on top cover w/ the Motorcraft print. Unfortunately I don't have experience with the Holley other than my truck came with one and I tossed it, which in retrospect I wish I hadn't.

 

[tirewater]

Th

These are vacuum ports?

One hole is an exhaust exit, the other pulls air in. If left like that, and your engine's EGR circuit isn't blocked at the intake or heads, exhaust fumes will be puffing out of one of the holes. I don't know what your ultimate goal is - i.e. go back to stock, pass emissions, get it running, etc...but for now I'd use a thin piece of metal stock and create a block off plate for it.

For reasons unknown, I took a picture of my spacer way back when I got my truck...here is what stock '76 CA emissions looked like with transducer & EGR valve.

You should look up the Holley 2300 manual and see where to plug in the EVAP/Charcoal canister line.

When I got my truck, the charcoal canister was plugged into a port underneath the top plate. I've attached a photo. My Holley was an older variant than yours, so may not be the same - and I can't say that's correct.

 

[Bronco_007]

Lol, too many different carbs in this thread. Yes, that's a Holley 2300 variant. The picture I thought being referenced was the carb with the evap vent on top cover w/ the Motorcraft print. Unfortunately I don't have experience with the Holley other than my truck came with one and I tossed it, which in retrospect I wish I hadn't.

Hahahahahahaha!!!

 

[Bronco_007]

One hole is an exhaust exit, the other pulls air in. If left like that, and your engine's EGR circuit isn't blocked at the intake or heads, exhaust fumes will be puffing out of one of the holes. I don't know what your ultimate goal is - i.e. go back to stock, pass emissions, get it running, etc...but for now I'd use a thin piece of metal stock and create a block off plate for it.

For reasons unknown, I took a picture of my spacer way back when I got my truck...here is what stock '76 CA emissions looked like with transducer & EGR valve.

You should look up the Holley 2300 manual and see where to plug in the EVAP/Charcoal canister line.

When I got my truck, the charcoal canister was plugged into a port underneath the top plate. I've attached a photo. My Holley was an older variant than yours, so may not be the same - and I can't say that's correct.

Oh wow. Wonder where I can get an EGR valve. Maybe I will start with the spacer manufacturer.

It runs fine… I think. But I’d like everything to be efficient, reliable, and safe. To me, that means all ports and valves have hoses or covers or attachments to serve function.

 

[raleigh_bronco]

Try Summit or Jegs first.

 

[Bronco_007]

Try Summit or Jegs first.

Any idea how to find my spacer manufacturer so I can get EGR valve that fits?

I found one that looks like holes match for bolts and inlet/outlet. But the face isn’t a match. Will likely need a gasket too.

 

[DirtDonk]

I was going by the OP's picture of a factory carburetor in post #7, that you re-posted in yours. Made me think it was still your carburetor we were talking about. Missed the fact that we were talking about two different Broncos here!
Thanks for posting your own pictures, which cleared things up after a bit of discussionations.
Holley traditionally had a 350cfm and a 500cfm carburetor. There may be numbers stamped into the body somewhere that indicate which one it is.

Which is the only real problem usually with jumping into an existing thread. Not that it's not a good thing to add more info and questions to someone else's information, but that people like me (old-timers mental acuity) miss the subtle clues of the questions being asked by different members!
My fault for not paying more attention. Or maybe it was just being on my phone for a couple of them, I missed it.
Sure, that's my excuse. And I'm sticking to it!

So no, you do not have a bowl vent because it was mostly a factory thing and only a very few Holley and Edelbrock carbs ever had them.
And the Edelbrocks are no longer available that way (I've got one, but haven't used it yet due to going EFI on everything and it's brother), not sure about Holley.
And it does not look like your early style charcoal canister has the added port for a bowl vent anyway.
What year is yours again? Certainly '73 or later, correct?

As others have said about the vacuum lines:
1. The big port angled upward from that "vacuum manifold" (commonly referred to as a "vacuum tree" because some different designs actually looked like trees) is for your brake booster.
2. The one sticking out of the base of the carburetor is for your PCV valve.
3. All the others will either remain capped off, or used for something if you ever install any other vacuum accessories. But they were there for things like automatic transmission vacuum modulators, and mostly smog-related items that have obviously been removed.

Regarding the charcoal canister connections:
4. The large paper fiber metal reinforced hose remains on that fitting at the air cleaner housing.
5. The second large matching one remains open to the air. Normally there is a plastic reinforcing ring ('70 to '72) or a cover that we call a "mushroom cap" ('73 to '77) that keeps out debris but allows air in.
6. Small one (is there only one?) on the canister is connected to the gas tank(s) via the condensing tank inside the cabin ('70 to sometime in '76).

Paul

 

[DirtDonk]

What year is your Bronco? Before you buy and try to plumb in an EGR valve, make sure you know what all else it was designed to work with. You might be climbing up a very tall tree, or down a very deep hole trying to source all the associated EGR controlling devices if they have all been removed. Which is what it looks like.

paul

 

[Bronco_007]

I was going by the OP's picture of a factory carburetor in post #7, that you re-posted in yours. Made me think it was still your carburetor we were talking about. Missed the fact that we were talking about two different Broncos here!
Thanks for posting your own pictures, which cleared things up after a bit of discussionations.
Holley traditionally had a 350cfm and a 500cfm carburetor. There may be numbers stamped into the body somewhere that indicate which one it is.

Which is the only real problem usually with jumping into an existing thread. Not that it's not a good thing to add more info and questions to someone else's information, but that people like me (old-timers mental acuity) miss the subtle clues of the questions being asked by different members!
My fault for not paying more attention. Or maybe it was just being on my phone for a couple of them, I missed it.
Sure, that's my excuse. And I'm sticking to it!

So no, you do not have a bowl vent because it was mostly a factory thing and only a very few Holley and Edelbrock carbs ever had them.
And the Edelbrocks are no longer available that way (I've got one, but haven't used it yet due to going EFI on everything and it's brother), not sure about Holley.
And it does not look like your early style charcoal canister has the added port for a bowl vent anyway.
What year is yours again? Certainly '73 or later, correct?

As others have said about the vacuum lines:
1. The big port angled upward from that "vacuum manifold" (commonly referred to as a "vacuum tree" because some different designs actually looked like trees) is for your brake booster.
2. The one sticking out of the base of the carburetor is for your PCV valve.
3. All the others will either remain capped off, or used for something if you ever install any other vacuum accessories. But they were there for things like automatic transmission vacuum modulators, and mostly smog-related items that have obviously been removed.

Regarding the charcoal canister connections:
4. The large paper fiber metal reinforced hose remains on that fitting at the air cleaner housing.
5. The second large matching one remains open to the air. Normally there is a plastic reinforcing ring ('70 to '72) or a cover that we call a "mushroom cap" ('73 to '77) that keeps out debris but allows air in.
6. Small one (is there only one?) on the canister is connected to the gas tank(s) via the condensing tank inside the cabin ('70 to sometime in '76).

Paul

Yeah, I kinda did hijack this thread, didn’t I? Sorry to the OP!

Mine is a 74.

I’ll connect the booster on the bottom per instructions by all here. And I’ll find a way to cap the in/out on the riser bracket. I’ll get a PCV valve for the top one under the carb.

Appreciate the guidance on the charcoal canister. I think I have seen the mushroom in the box-o-parts from the PO.

Yes, the small tube is still there, connected to the condenser inside the cabin. But that condenser’s days are numbered. It is coming OUT of the cabin. Pronto!

Thank you all!

 

[Oldtimer]

At this point in history, what years are the parts currently installed on a Bronco in its 5th decade?
Your current intake manifold may not even have an exhaust crossover that aligns with the hole in the EGR spacer plate.
You may need to do some disassembly before you can proceed.

 

[Oldtimer]

I suspect the riser bracket is already capped.
Otherwise you would have vacuum and exhaust leaks.

 

[Bronco_007]

Hmmmmm. Will check!

 

[Bronco_007]

I suspect the riser bracket is already capped.
Otherwise you would have vacuum and exhaust leaks.

You’re right. They are plugged.

 

[Bronco_007]

I’m going to check both vents on the top corners of the valve covers and see where the hoses run. I’m pretty sure the passenger side vent is currently piped into the air intake. But I’m not sure about the driver vent. I’m wondering if that one should run to the valve under the carburetor. Where the PCV normally goes. I’ll get more pics. Thoughts?

 

[Steve Tool]

When they set up for long period of time, they'll develop scale in the gas tanks, with the cheap watered down crap they sell at the pumps now a days its very common, I went thru this and had to drop and clean both tanks, I use clear inline fuel filters now to monitor the fuel lines for trash, and I only fill up with non ethenol gasoine with a cap ful of marvel mystery oil, it keeps everything clean from the tank, to the carb

 

[DirtDonk]

I’m pretty sure the passenger side vent is currently piped into the air intake. But I’m not sure about the driver vent. I’m wondering if that one should run to the valve under the carburetor. Where the PCV normally goes. I’ll get more pics.

Yes.

Your pictures appear to show the standard orientation for a ‘71 through’77 model.
The engine doesn’t care which side is IN or which side is OUT. It’s a simple recirculation system.
But logistics and convenience (or whatever) dictated a change from the passenger side valve and driver side vent, to the opposite which is what you have now.

The passenger side is a simple elbow fitting vent that allows clean air back into the crankcase via the molded hose from the filtered area of the air cleaner housing.
The driver side with the valve gets full vacuum through a PCV valve mounted in the oil fill cap to full vacuum at the base of the carburetor.

That’s all it is. You just have to put it back to stock in your case.
The only reason to change it some how through the use of a different valve would be if you had a big cam or other major modifications to the engine.