Hello I have a 96 F-150 with a 4.9L I have been having issues with the emissions. I was checking things out and found that the secondary air system going to the catalytic converter was hook up but there was a cap over the tube. Since we have owned the truck we have never had to replace the converter. So My question is why is it there? Was it a mistake from someone else? I think this has been my issue from the beginning. I have changed out O2 sensors, EGR valve the light goes out then after awhile I start getting the light. check out things find nothing wrong Reset the codes and again after awhile it comes back on.. The only reason I found it this time was repairing a exhaust leak at the exhaust manifold. I can not see how the secondary air system can work properly with the plug there. so I just want to make sure before I take it off. Any thoughts on the matter?
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Having an older F150 with the 4.9, I can say the air tube on mine is connected to the converter assembly. The air tubes always seem to rust and break where they connect to the converter. Maybe a technician plugged it. Take a closer look at the converter, there may be another cap on the nipple where the air tube connects.

Also, what codes are being set?

 

Raski
Thank you for answering this last time I got the following codes.
1) P0411 secondary air injection insufficient flow detected
2) P1408 EGR flow out of read codes range
3) P1000 check all systems is not complete since last memory clear
The EGR valve is new, also the solenoids, also the vacuum hoses and the EGR transducer. The only cap I have seen is on the nipple where the air tube connects. The way I am understanding this is that I need to remove the cap from the nipple and clear the codes take it out and see what I get .

 

On the 4.9, there is a group of solenoids ( TAD, TAB) mounted on the driver's side rear of the engine just below the valve cover. By varying the electrical signal to them, vacuum is controlled for the application of the EGR and secondary air injection system. Check for proper vacuum, broken vacuum fitting at the solenoids.It is common for the plastic vacuum tubing to disintegrate after many years. Faulty electrical connections. I would even check for proper manifold vacuum and make sure your vacuum storage canister is not leaking.

 

The operation of the various valves, TAB(thermal air bypass) TAD thermal air divert) and diverter valve, can seem confusing to someone that does not understand their function. Some folks have even gone to the point of removing them ,creating other problems. There are anti-backfire valves there to protect all those components.

I would suggest you look closely at the O2 sensors that read the exhaust and send info back to the computer letting it know when something is not right.
I can see you attempted a reset, and that didn't help.

There are also thermal vacuum valves that screw into the engine . Their function is to allow vacuum to operate some of those valves after a certain temp is attained.
Be careful around them the extensions break off easily after exposure to constant heat. Sometimes they can be hard to get.

 

Start with the cheapest, easiest and most likely item in common with all your problems. That would be vacuum lines. I wouldn't do anything else till I verified they were intact and not leaking.

 

Sorry for the delay in getting back to you. I got involved helping a freind fix his tractor. Ok back to my problem, I did find another vacuum line bad and replace it with new. I was located between the firewall and the engine. After doing this I deleted the codes and went for a drive it was about 45 min run in town and highway driving. Just as I pulled back into he driveway I got the check engine light. So I ran the code which I was happy to see it wasn't the emission problem but it was a to rich of fuel in banks 1 & 2. Well that was my fought for not reading the all of the information on the new injectors. Here is the Info on both the old and new injectors:
A) OLD INJECTOR INFO A) NEW INJECTOR INFO
B) Bosch EV1 B) EV1 Jetronic
C) 4 port hole C) 4 Port hole
D) Flow rate @ 43.5 PSI / 3 Bar D) Flow rate @ 43.5 PSI / 3 Bar
E) 14lb per hour E) 14.66lb per hour
F) 107 G per min F) 110.7 G per min
G) N- ( Heptane) 143CC per min G) 154CC per min
Ok so I can not send the injector back so is there a way to correct this issue. Like maybe changing the O2 sensors to the next higher up or sending my ECM in and have it reprogram or is there one higher also. I am open for suggestions. I thank you for the helping the emission issue but i caused another.

 

My advice is to put the original parts back on, retest and proceed with diagnosis if needed. Changing from stock is just opening a can of worms.

 

Just because places sell things that we think will enhance performance. is not always the best way to go.
Yes , some do help. but something to consider,
The manufacturers invest a lot of time , $$$, and testing to put a product on the market that will perform satisfactorily, reasonably economical and somewhat reliable.
When we start altering some of the specs, we could be asking for trouble. We all would like to see an engine go 500,000 miles without any kind of trouble, but we're not there yet. Yes there are folks that have produced some gains , but at what cost. Some have pushed the powerplant to the MAX and been pretty lucky.
Because reliability is an important point to keep in mind, the Manufacturers have to keep in mind poor reliability could mean poor sales and they probably would like to have pushed a little more but there is always a price to be paid for exceeding the limits of what something can do.
After that winded explanation , I have to agree with raski, stick with stock and hope to get more than your moneys worth.

 

Thank you for your answers I figured your answer would be go back to the same Injector as the ones I removed