dfwcowboy57

I have this code now & have a 1996 v8 5.0, what & where are these soleniods & valve check? How do i test the smog pump?

memoniz

I don't know if your system is the same, but on my 4.9, the last thing I did was replace the EGR VACUUM SOLENOID and the EGR PRESSURE FEEDBACK SENSOR. It drove for about 125 miles before the light kicked on. I used a waiver to get through inspection. But I have put a can of Sea Foam in my last three fill ups and cut off the light fixing something else. It hasn't come back on yet after about 325 miles but I'm not holding my breath. I've previously replaced my upstream O2 sensors, the AIR check valve, the EGR valve, replaced some vacuum lines, and blew out some vacuum connection points. The later stuff didn't change much (came back on after 30 miles), but the first two parts listed changed the results. Also, that was the first time trying Sea Foam. There are two other solenoids or sensors that you can only by from Ford that I have not tried yet. I can't seem to pull them up on the computer right now but I would try the Sea Foam and clean all the lines out you can first. Then start with the parts.

Warlockk

Its not a complicated system but it has many parts. You will need a schematic to diagnose it properly. You should be able to find one online or you can pick up a Chilton's or other shop manual. Here's the basics. At cold start the air pump ( under your alternator ) pumps air into the heads to warm the system and reduce emissions by burning the extra fuel injected before warming up an going into closed loop operation ( how the fuel system normally runs ). After a few seconds the computer switches the valves to send air to the cats to warm them up. Cats must reach a certain temp before they work. When the engine meets certain criteria it goes into closed loop and the valves switch so the air blows out into a silencer under the hood. The system is monitored by the O2 sensors. When running a self diagnostic the computer switches the air valves on and looks for the extra oxygen. That code says it didn't see enough of a change. The first step is to verify the problem. For this I recommend clearing the code and driving it normally then retest to see if the code returns. It may take several days for the computer to hit all it needs to complete a drive cycle test. If the code comes back you need to check that the voltage is getting to the actuators to operate them. That the actuators and valves are getting vacuum from the intake manifold, holding vacuum and switching when they receive the electrical signal. That the valves and lines aren't blocked and attached where they need to be. And that the pump is working. A hand vacuum pump, vacuum gauge, multi meter ( volt meter, DMM) and a schematic should make it a straight forward test. Oh yea a big exhaust leak can cause a fails reading too.

dfwcowboy57

Thanks! I found that a hose was not connected to the divengce valve behind the engine, after that the engine light went out, thanks everyone for all the help!

magic1

do to stroke I lost a lot of memory and I have been throwing a P0411 code and needed your help to diagnose the problem.
Thank you so much for posting your day to day experiences and what you learned, it was very helpful.

Warlockk

Cool glad to see it worked out.

mart0399

I have a 1996 F150 5.0L with 68K miles that I picked up at an auction. Drove it for ~1000 miles before I picked up P0171 and P0174 lean codes that I have been troubleshooting. Checked all the basic stuff; no intake leaks, no exahaust leaks, no vacuum leaks, fuel pressure checked out (30 psi), vacuum measured 19" at the brake booster, smoke check indicated no leaks. O2 sensors behaving as they should. I replaced the fuel filter to see if that would improve pressure as I felt I was at the low end of factory spec (30-45 psi). The truck, otherwise ran fine, but I could not clear the codes as the LTFT on both bank was consistenty high and thus, flaggind the codes. I then decided to change the plugs, plug wires, distrubutor cap and rotor as they seemed tired, particularly the distributor cap. I used Motorcraft spark plugs (gapped 0.054"), Motorcraft wires, and Accell distributor cap (wanted brass terminals). I made sure to follow the recommended wire routing to account for crossfire. Interestingly, the motor runs a bit rough under load, but somewhat okay at idle but interestingly, I flagged a P0411 (Secondary Air Injection Incorrect Flow Detected). Also, the PCM is registering an ignition advance of 17° at idle (seems high). I do not recall ignition advance reading prior to ignition parts upgrade. Does anyone think that the the ignition upgrade somehow triggerd the P0411 code?

What should I check next? Should I adjust the timing?

manicmechanic007

Use the pinpoint test steps for each code
That way you just do not throw parts at it