I picked up a '95 F150 last weekend. I thought it had a manifold leak because it was making the classic "ticking" sound under acceleration. The PO took out the air box for some cone filters. Can I simply plug this? Air is pulsing out of it which I am sure is the cause of the sound. I assume it went to the air box? It's located on the passenger fender.

Thanks

 

Doesn't look like my photo link worked. Anybody have a PDF link to the EGR system schematic?

 

What engine?

Regardless, I would trace the line back to it's source to verify what it's function was - I don't believe what you've found is related to the EGR. If you're going to cap it off, best to cap it off from the source and get rid of stray vacuum lines. Most of the fittings on my vacuum tree are capped off.

 

More info -

The piece in question seems to be a check valve. The air comes out of the pump, goes to a diverter which, according to my brother's Mitchell system says that it draws air back through this secondary inlet "under certain cold weather circumstances". If it is the check valve, it's shot cause I can pass air through both ways. What's confusing now is that the PO removed the airbox and I am not sure what other stuff he cut. The check valve on the truck (with a Ford stamp in it) is slip on connections for both sides and mounts to the fresh air instake canister for the air pump. The replacement parts (including from Ford and aftermarket) look the same but one side is threaded.

Here's a photo (trying again..)



Here's another look -

 

I don't have a 5.0, but I believe that is supposed to be open. I could be wrong and I'm sure I'll be corrected. However, my 4.9 has something similar and it is open as well.

 

It's the 5.8. I think that it's OK to be open, the problem is that the diaphram (if it is a check valve) is shot and air is pumping out of there all the time. Under proper operation, it should only allow air "in". Under acceleration, it sounds like I have a manifold leak. I guess I could still have a manifold leak. I was thinking that the air blowing out of here under full RPM was the cause of the sound.

Still don't know why mine has slip on connections on both sides and the replacement has threaded on one side.

 

If you have a "tick", it's probably the manifolds. There is nothing about that can that can really make a "ticking" sound.

IIRC, that can is just a muffler for the air when it's not being diverted to the cat/heads.

 

That's not as it should be. Your smog pump plumbing has likely been removed, with the rail left behind and open to atmosphere. You should cap it off if you don't want to be bothered removing the rail.

 

My air pump system has been modified and the air injection rail was removed by the PO. However, the head was plugged and the air line that was going to the air injection rail was teed into the air line going between my front and rear cats. I'll have to look at my setup again, which is currently sitting on my garage floor while I'm replacing the head and such, to see exactly where I saw that piece. I know I have the muffler attached but I thought the piece erupert66 posted a picture of was the inlet, although I too could be missing something or remembering incorrectly.

As to why erupert66 new check valve is threaded on one end, I couldn't say unless the one that is attached to the top of the air injection rail is threaded so it can be replaced. Anybody have ideas on this?

 

So, as far as I can tell, everything for the air pump system is still installed up to the point of this device. At this point, i don't know if it's a "muffler" or a check valve. I have the canister that feeds cool/clean? air to the pump. the pipe comes out of the pump and back to diverter that either sends it towards the back of the engine or back towards the front where the hose connects to this unit. this unit is welded to a bracket which is attached to the back of the canister that provides the supply air to the pump. The only mod I know of is that the PO removed the airbox and put on K&N type filters. I'm not sure what a "stock" underhood should look like and I've done a bunch of google image searches trying to see a good underhood shot but haven't found one.

 

Mine is open as well. So is my buddys. (both 5.8's)

I think thats normal ( I hope )

 

Thanks for the replies. I think we'll call this case-closed.

 

Good luck with your ticking noise!

 

That's just a muffler/noise suppressor and it's supposed to be open. If the air injection system has been modified and doesn't connect to the heads anymore then you may as well remove it completely because it's not doing anything. All that plumbing can be removed but the vacuum lines coming off the TAB and TAD solenoids near the coil have to be plugged or removed(red lines are vacuum source from the intake manifold and other colors are control outputs from the solenoids), and the electrical connections to these devices must remain attached. The ports in the back of the heads can be plugged with 5/8x1" coarse bolts and copper washers, RTV will burn off and crimping tubes is not a suitable alternative for plugs, there cannot be any leaks in the exhaust system upstream of the O2 sensor or engine performance and drivability will suffer.

 

Just a little trivia for you: There were some 4.9's that came from the factory without air injection tubes going in the head and only an air line going down in between the cats. I used to think that all had air injection in the heads too until I found a couple of them at salvage yards that weren't modified. In fact, the latest year I saw with this setup was 1995 on a Speed Density system. I'm not sure if any other engines received this treatment from the factory or not.