Ford F150 - Manual does not answer my PCV valve question - Please help

Smoglord

1994 351w

I had some check engine light trouble and am going through the steps to rectify. I just picked up the truck 2 weeks ago. I replaced the PCV valve, started it up, and immediately noticed a loud hiss from the top hose connector on the PCV. The only trouble is that on the old one nothing was connected to it, so I don't know where it goes.

Also, in the middle on the intake manifold there is some type of vaccum line coming out that should have a hose attached to it. But the dealer just put a 2" hose on with a clamp and plugged it up with a bolt. Again, I don't know where t goes.

It should be noted that both of these (Upper PCV line and strange intake manifold line) have vaccum on them, and if you put your thumb on them, the engine idle goes lower.

Finally, I bought a Breather filter from Autozone, but there is nowhere to put it in the "Air box" and I don't know what, or where the hose comking out of the breather connects to. Any insight would be much appreciated as the havnes manual simply says to install in the reverse order it was removed.

Steve83 · Posted: Sat Oct 14, 2006 3:27 pm Post subject:

The factory PCV doesn't have that small upper fitting. The replacement should include a plug molded onto the valve like a plastic model. Break it off & install it. Or just swap the new one for the original PCV's plastic elbow.

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Check your vacuum map to see if there should be anything connected to the vacuum tree on the intake.

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The breather filter goes inside the air filter box, below the filter (on the dirty side). There should be a hose to it from the oil filler neck. I recently replaced the engine in this '94 5.8L and there might be some shots in that album that will help you.
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. '99 CV RIP

Smoglord · Posted: Sun Oct 15, 2006 6:18 am Post subject:

Steve83 those pictures are awesome and exactly what I was looking for. The PCV I removed is identical to the one I replaced it with and looks like the one in your pics from what I can tell. I have a small hole in the air filter box that looks like a hose could connect to it, but no hose, and my valve cover doesn't have that fitting on the filler neck.

Finally, I don't have a tree like that on my intake, just a single vacuum inlet that someone plugged up. I'm beginning to suspect this might not be the original motor.

Steve83 · Posted: Sun Oct 15, 2006 10:39 am Post subject:

Sounds that way.

But are you saying your new PCV valve has only 1 port on top, and NO hose connected up there??? Most aftermarket PCVs look like an "F" with the top port being noticeably smaller. That's what I was describing before. Ford PCVs look like an inverted "L" or Greek letter gamma, with only one top port, which should be connected directly to the PCV port on the plenum.

If your upper intake plenum has only 1 port on the top L side (as shown in the lower L foreground of the last photo above) with no tree in it, then someone removed the tree AND your PCV port will be on the back of the plenum facing the firewall.

Smoglord · Posted: Mon Oct 16, 2006 3:10 am Post subject:

Steve, sorry for the misunderstanding on the PCV valve. Yes it does look like an F. So there is a short and fat hose connecting the lower part of the valve to the intake manifold (I think, it's hard to see) and the upper part of the F has vacuum or suction. But I don't know what to connect it to because there was nothing hooked up to the old one.

On a positive side note, I managed to find a filler neck for the valve cover that has an inlet for the air hose coming off the air filter box.

Lastly, I checked and there is a vacuum tre on the intake manifold almost where it is found in your pictures of the 1994. The only difference is that Just to the right is another vacuum intake. It's a single metal tube coming off the manifold. Again, I don't know what it connects to. But if the engine is running, and I put my thumb over it, the idle goes down.

Steve83 · Posted: Mon Oct 16, 2006 6:13 am Post subject:

Right. Plug it, as I said in the first post.

The other vacuum port is shown here, and I think that hard line goes to the MAP sensor.

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Smoglord · Posted: Tue Oct 17, 2006 3:54 am Post subject:

Steve, that is incredible. I think I finally got it. I will let you know once I get all my lines hooked up. I can't thank you enough.

On a seperate note, I noticed you selected the hooker headers in the pics of your engine swap. What kind of header gasket would you reccomend as I have purchased the same ones.

Steve83 · Posted: Sat Oct 21, 2006 10:07 am Post subject:

I didn't choose Hookers, and that's not my engine. It's one I installed for that guy, just a few months after I changed the body on his truck. His is a dark blue '94; mine is a black '83 w/4.9L; my brother-in-law's is the lighter blue '93 shown in the last 2 pics above.

I used the gaskets that came from Hooker on his engine.

Smoglord · Posted: Mon Oct 23, 2006 3:45 am Post subject:

Good to know. Anyways, from your pictures I discovered that the vacuum tree (if facing the engine from the drivers side) is on the leftside of the intake manifold. The line that runs to the MAP sensor is plugged into this tree. To the right side of the intake is that hard line I mentioned that they had plugged with a hose and a bolt. The engine runs much better after removing the plug, and I think they hooked the MAP vacuum line to the tree because they did not heve a propper fitting to put it where it belongs. What I will have to do, is find out where each vacuum hose connects to the tree, and which ones need to be plugged. Even though both come off the intake, I find it hard to believe that it will operate properly in the manner they had it hooked up.