While diagnosing a rough idle in the new 79 f250 4x4 351m, I began tracing vacuum lines and found some big trouble. I need help identifying 3 parts so that I can replace them.

1.) A part of the pulley system that isn't connected to any belt. The device is directly under the alternator and has a large line running to a silver canister, and that silver canister has one large vac line that should lead to the top of the block but is broken and some smaller vac lines that run elsewhere.




2.) The silver canister itself.




3.) A small part that's rusted out that connects directly to the canister and then to the smaller vac lines. The part number is partially rusted and cant be cleaned to be read legibly. I tried some open ended google searches and just kept getting carb rebuild kits.




I'm guessing this should solve my idle issue... Thanks for the help.

 

So the full system zoom out photo looks like this with the parts I need identified numbered according to my original post.

 

Well, That is a smog pump, so I am guessing the rest is part of that. Search on here for smog, might be able to identify parts or find out how to delete.

 

http://www.ebay.com/itm/1976-77-NOS-Maverick-76-89-Bronco-79-80-Mustang-Thermactor-Idle-Vacuum-Valve-/231484078465?pt=Motors_Car_Truck_Parts_Accessories&hash=item35e586b981
Here is one for sale.

 

OE Ford Mercury Air Bypass Diverter Valve D5ZZ 9B289E D5ZE ea 6770s | eBay

here is another

 

smog pump 1979 Ford F-250 Ranger XLT 5.8L | eBay

 

Thanks for the help identifying it gentleman. The truck runs without the smog pump connected so I'm tempted to take it off, BUT I cannot find any good write-ups on it here on our forums but read around a bit on the net. The net is scaring me a bit.

People are saying that cam timing should be adjusted, distributor should be re-curved, engines are pinging etc. If all I need is a the parts listed, a hose, and a belt, then I'm tempted to just keep the smog.

Can it be safely assumed that if the smog pump pulley spins then it works? If not, how else would I test it?

Anyone know of any good write ups so I can weigh my options?

 

If you were to remove EGR, those would be concerns. The air pump ("smog" pump) serves only to pump extra air into the catalytic converters so they can oxidize the unburned hydrocarbons and carbon monoxide. If you aren't running cats, you don't need it; if you are, they won't be particularly effective without it. It does nothing as far as engine performance.

I think the confusion is coming from people referring to all emissions controls devices from this era by the term "smog" ... some of the others would affect engine calibrations. The air pump will not.

 

Yeah I don't want to eliminate the EGR system or anything else like that, but I would like to remove the parts stemming from the smog since they all need replaced and I just went outside and the Smog Pump pulley is completely seized.

Removing all those parts seems somewhat self-explanatory since its mostly just the parts that are contained within this post and then plugging a couple of vac lines. The only thing that stumping me is coming out of the top of the block right in front of the air cleaner cover is a port that should connect to the Air Bypass Diverter Valve and I'm told and it would appear that it is an exhaust port. How should I go about plugging it?

 

Do you have pictures of what you're talking about? The block isn't exposed up near the air cleaner - would have to be the intake manifold?

 

#1 is the part I am trying to identify and figure out how to plug. Now that I'm not tired and I'm thinking straight, you're right it couldn't be exhaust because the hose that comes out of the Air Bypass Diverter Valve that should be leading to it (#2) is rubber and its on the intake near the carb.

I was cruising Google when I said it was exhaust but suppose they were talking about something else. But why would that port coming off of the intake not being connected to a hose turn the bottom of my air cleaner black like the bottom picture? Between Google and the black on the air cleaner and the fact that it eventually connects to the smog pump, I thought I was reading google correctly when it said exhaust. I'm no ace mechanic.

Also read somewhere that it may be a check valve? All I really want is an idea on how to plug it properly so I can remove just the smog pump and air bypass diverter valve since they both dont function

 

Hmm ... I'm not familiar enough with the 351M to say for sure what that is. Maybe someone who has one can chime in? I would think if the engine has been running OK, it can't be directly open to manifold vacuum. Could be some sort of PVS or something?

 

Running enough to get from A to B, but as I said in the original post it idles rough and I'm wondering if this is why. Obviously it vents some from the engine judging by all the black on the air cleaner. I didn't tune the carb yet which could be my problem, raining too hard.

 

I'd throw a big vacuum cap on that opening for a start...

 

That port with the broken hose needs to be plugged. It goes directly into an exhaust passage in the intake manifold. There is apart missing on your truck, I think it is called an anti backfire valve. There appears to be something screwed into the hole in the manifold, just remove it and find a pipe plug the correct size and thread count and use that. Right now you are pumping exhaust gas out of that hole.