85 Ranger Exhaust Part Identification

[andyh13]

Hello,

I have inherited an '85 Ranger with a 2.8 V6. It has been modified to replace the original feedback carb with a 2150 (it looks like this one is for an automatic transmission, but the truck is a manual).

The ignition has also been switched over to HEI.

I am not very mechanically inclined. Sorry if the answer to the following question is obvious:

What is this part that seems to be unhooked? It looks like it goes into the cat.

And what is this big open pipe?

Am I correct that it's coming out of the exhaust manifold? But why would it go up and not down? Is it EGR related? I think the old owner stripped out a lot of emissions stuff when he switched it over to the 2150. Should it be covered with some sort of plate?

Thank you in advance for any insight you can provide.

 

[adsm08]

The piece on the manifold looks like it is for the air heater, which is just used to help get to temp and out of choke mode faster. Nothing needs to be done with it.

The piece on the passenger side is part of the secondary air injection system and should go to the cat. There should be an air pump and some other pieces scattered around, which may be gone.

 

[Curious Hound]

The piece on the passenger side is part of the secondary air injection system and should go to the cat. There should be an air pump and some other pieces scattered around, which may be gone.

I though that was the fitting where you connect a hose to suck start the engine when the battery is dead.

 

[andyh13]

The piece on the manifold looks like it is for the air heater, which is just used to help get to temp and out of choke mode faster. Nothing needs to be done with it.

The piece on the passenger side is part of the secondary air injection system and should go to the cat. There should be an air pump and some other pieces scattered around, which may be gone.

Is there anything I need to do to that piece of the secondary air injection system to make the engine run properly? Or will it only affect the operation of the cat?

 

[adsm08]

Is there anything I need to do to that piece of the secondary air injection system to make the engine run properly? Or will it only affect the operation of the cat?

Should really only effect cat efficiency, but you will probably have a massive exhaust leak.

 

[andyh13]

I haven't done much with the truck recently, but I was having a conversation the other day with a person who has worked on cars much longer than I have, and this person claimed that lack of backpressure could cause a carb to run lean.

I had not previously considered this. Do you think there's any merit to it?

The truck idles pretty rough, but that saga is chronicled over at: https://www.therangerstation.com/forums/index.php?threads/85-2-8-idling-too-high.182625/

 

[adsm08]

No internal combustion engine ever has benefitted even a tiny bit from backpressure. Physics doesn't work that way.

What does happen is that with a properly tuned exhaust system the exhaust pulse from one cylinder creates a vacuum behind it that helps pull the next pulse along, which is an effect called "scavenging". It helps the exhaust flow easily, but can be lost by having the wrong sized pipes. Too small and it creates a restriction, so the scavenging effect isn't enough. Too big and you don't have the exhaust volume to fill the pipe and scavenge it, so you loose the effect altogether, now the engine has to work to push the exhaust gas down the pipes.

You get some backyard mechanic who puts a huge "free-flowing" exhaust on their car, loose power, and then they think "Oh, it must have needed that "back pressure" to run right" and that's where the myth comes from.

If your exhaust is leaking that needs fixed, but it shouldn't cause it to run lean.