eec-iv and early eec-v fords love vacuum!!!

PLEASE. SEND. PICTURES. OF. YOUR. ENGINE.BAY. AND. VACUUM. LINES.


I can tell you very easily what areas to pay special attention to. is your pcv valve still in the grommet? sometimes thye pop out when the rubber gets old.

 

Pics have been added to original post!

 

hmm. the vacuum hoses have been replaced mostly. i advise a smoke test.

 

I'm not an expert on the I6 engiens but I thought air injection was phased out when OBD2 was introduced. Can anybody confirm that?
If it was still used did the later engines still have that air injection manifold in the head? What about the TAB/TAD solenoids, wasn't the system simplified to a single control solenoid and valve in later years?
I can't help but think this truck has the wrong engine in it.

Another thing I don't like, with the downstream air line disconnected from the cat and welded shut where does that air go now? Has the system been rejigged so it injects air upstream all the time? If so that is a big no no, as has been stated before there can be no fresh air in the exhaust upstream of the O2 sensor once the EFI system goes into closed loop. If that is what is happening now it needs to be changed, in fact if the factoy cat is gone there is no point to the whole air injection system being there at all, I suggest you take it all off or at least make sure it's just recirculating air back to atmosphere all the time so it's not going into the exhaust. The easy way to do that should be to disconnect and plug the vacuum lines going to the bypass and diverter valves.

 

the AIR setup for 1996 f150 with AIR is universal, california / federal spec wise so it has 2 of those check valves threaded into the air manifolds and the system and I believe it uses one vacuum switch as you mentioned, the other 2 are for EGR.

AIR is required only because the trucks use a 2 way cat followed by a 1 way cat and its far enough away from the engine itself to not heat up fast enough as well. aftermarket 3 way universal cats then wouldnt need AIR either. But all of what you say here is true and good. as long as the truck thinks its genuinely in closed loop. any misrouted air or deviation from intended design could possibly be skewing the AFR badddd!

 

to determine stock engine, OP, does your hood cotain this label and what does yours look like
the letters TWC is two way convertter, not sure what OC is
AIR is air injection, 2HO2S is 2 heated o2 sensors (For fuell control), EGR is exhaust gas recirc, and SFI is sequential fuel injection
Edit: there are 2 AIR vac solenoids then, my bad. making sure those were not hooked up backwards or whatever when the lines were changed may help explain away things,.. but since you dont have Cats, id honestly just look at removal of the systems components like con said above. That will set permanent codees that can only be tuned away sadly. and OC means oxidizing catalyst.

 

So after I fixed the exhaust leak and it started running worse than ever, I was thinking about the Air pump and how if the pipe was welded shut then that air is not going where it needs to do why would I have the pump running, so I got a shorter belt and bypassed the air pump, and it’s started running a little better, so I think the most economical solution would to get rid of that whole pump system maybe, I didn’t block off the pipe to the pump itself so I assume that itself is causing a leak. Should i remove all of that stuff and just plug the holes, if so is there a thread or video that shows one how to do it the correct way? I don’t know what the assembly is called but it’s the one next to the intake manifold on your left when your looking at it.

 

You have the check valves threaded into the exhaust manifolds to contend with. if you block them up manually you may "seal" the system id think , im guessing they are rusted partially open they are old. one is right next to that manifold thing you asked about (did you cap the vac line to that?), those hoses can easily be removed from the pipes that have the check valves i speak of. the one is easy to get to the other is a bit more work because of placement.

Youre gonna want to replace your SMOG pump either with itself not hooked to anything (if the bearings are good, do it) or you want to get a bypass bracket. The stufff on the fender liner leeading to the pump can all come out thats just a filter and muffling assembly. Lots of new room by the vac tanks and battery from that.

 

I just smoke tested the system and didn't find anything wrong with the SMOG or EGR lines, what I did find is that the breather valve on the front of the valve cover is loose broken and doesn't sit properly so I'm going to replace that. I also found another hole in the back that has nothing going to it, It's just a big hole with a gromet on it letting all sorts of crap in my engine. What is supposed to go in there? I also need to replace the valve cover gasket. I also found that another exhaust leak in the rear, when they deleted the cats I don't think they clamped it down all the way. I went a little to had with the air gun on it and snapped it so I need to grab another clamp, or get one of those flat band exhaust claps cover the lip in jb weld a pray it seals right.

I'm waiting on the right size caps to seal the system.

 

.. I asked you to check this before!!! YOURE ENGINE HAS a massive PCV leak!!!!!
YOu dont have a PCV valve installed! Follow the stiff rigid hose that comes out your intake near your vacuum tree, one thick hose with a 90 in it shortly after leaving the intake, if that hose has nothing or a PCV on the end, i cant believe how this thing was running as :"well" as it has

 

Yeah i’m not the smartest lol. do you have a part number for the valve in the rear of the valve cover?

 

Do you want it installed too?

 

The front PCV valve is still attached to the front, but I can’t find anything relating to the rear home with the grommet in it, I am also unable to find any hose that would attach to it. Would you happen to have a picture of it properly connected or anything like that?

 

Here is the PCV Valve that AuroraGirl is referencing"

There are a two options I see, one for a RWD and one for 4x4. Not too sure what the difference between the two is, but here are the part numbers:

RWD: https://www.rockauto.com/en/moreinfo...=5052&jsn=1990
RWD Ford/Motorcraft P/N: EOTZ6A666A OR EV111

4x4: https://www.rockauto.com/en/moreinfo...=5052&jsn=1991
4x4 Ford/Motorcraft P/N: E1DZ6A666A OR EV118


I couldn't tell you the hose size, maybe 3/8" ID? I'm not too sure it matters as long as there is a good seal on PCV and the plenum.

 

Before replacing the hose, you should determine if yours is in good shape or not. This is a molded hose, and using bulk hose requires a lot of extra work to prevent kinking (in my experience) so buying the proper replacement hose would be ideal. I can get you a link if you find that yours is not in good shape. As far as grommet, I found a grommet in the Dorman HELP! section at my local auto store, just take the one in the valve cover out and search for a new one to match. As for valve, im not sure whats the difference in the valve, but if yours is still attached to your Hose it might be in good shape. they can be taken apart and cleaned/inspected if its an OEM motorcraft.