Hi guys, about a month ago I ended up getting a 1996 f150 with a 5.0 for 1700 bux. It ran fgood for a couple of weeks and now about every other time I drive it stalls out on me when Im driving it and it wont start back up.

So far I have put a new cap, rotor, plugs, wires, fuel filter, starter solenoid (engine bay and starter mounted), and a new Egr valve on it. I put the Egr valve on it after i took it to autozone and had the check engine light tested. I think the code was P401, the old one was in pretty bad shape. it ran fine for about a week and a half and then the light came back on. Now it is a P411 which is the secondary air system fault. Now the truck stalls and wont start until the next day. Its not the starter because the motor turns over. I know i'm getting fuel, I can hear the pump turn on and I checked it when i replaced the fuel filter a couple days ago and i know the spark situation is good. I checked it two different times before it got towed home and the battery is two months old


Im somewhat mechanically inclined, but I have no clue what the secondary air system is or where to find it. I did check all the hoses that i could for leaks and could not find anything. A little help and some patience would be greatly appreciated. Thanks guys.

 

Secondary air system ? Could that be the air pump ? Just a wild guess cause I can't imagine what a secondary air system could be.
As for the die/no start that sounds suspiciously like a dying pip (distributor pickup module). Or coil.
I know you said you have spark, but did you test it when the truck was not working. I use another spark plug and a booster cable - one end of the cable on the metal of the plug the other end on ground, pull the easiest spark plug wire and plug in the spark plug, crank it and see if there's spark.
If you had that ready then when it dies, you can pop the hood hook it up and check for spark then.
It's pretty common for them (PIP)to work intermittently just before they die completely.

 

I dont know if this info would help or not but I replaced the solenoids because the one on the starter was bad. there must have been a short and the positve bolt was broken and a melted the top portion of the solenoid that was plastic. I also checked all the wires leading to and from the battery for bad spots and everything looked fairly new. the guy i bougt it from did say that his kid tried to jump it and hooked up the cables backward. Which explains why all that stuff is new plus the battery. Im just trying to tell you eveything that i have done to it since I got it to help with the process of elimination.

 

I did check the spark with a booster cable after it died. I was getting spark. I learned that trick with my last truck. I don't know, The guy who had it becre me bought it new and used it as a fourth vehicle. It proably wouldnt hurt to pick up a new coil anyways, the last time it had a tune up was in 1999 at like 78,000 miles. The guy had it written under the hood in marker. Now it has 165,000. I was surprised at how cheap parts are for these trucks.

 

Always a real good idea to give as much history as possible.
Reverse polarity could have fried all kinds of things.... But since it has been running since, chances are good that what got fried is fixed.
Start with the basics, it's probably something simple like the pip, coil, or it could be something as simple as a sensor.
Before throwing parts at it you should arm yourself with - A way to check for spark, a fuel pressure gauge, a test light, and a cheapy voltmeter.
Less than 100.00 total there and you'll be able to test things before replacing them - you'll save more than 100 and you'll still have the tools.

 

If you've got spark, the rest is timing and fuel.
Fuel first - pump coming on is good, but how much pressure is it producing ? You need 30 to 45 - with 30 being barely enough to make the truck run. 20 and it won't go.
The other fuel possibility is the injectors not getting a pulse and therefore not opening - that would be wiring or computer.
Best way to see if it's fuel is get some starting fluid, pull the plastic intakes off the throttle body and spray it in for about 3 seconds, then hit the key. If it fires, it's a fuel issue. If so check pressure first. You'll need an led tester to check for injector pulse.

 

I have everything but the fuel pressure gage. The neighbor should have one . I will grab it from him when tonight when we both get in from hunting...

 

I did hit with starting fluid today. I sprayed it three times. The first time it fired and rolled over (very roughly) for about 3 seconds and died. The next two times it did nothing.

 

x2 on pip or coil, the majority of these random dies and won't restart for xx length of time it's one or the other. Also just because you get spark doesn't mean it's a strong spark, should be blue in color not white. Coils aren't that expensive and since you did the rest of the tune-up you should get that regardless. I don't advocate throwing parts at a problem but if it's something that should be done anyway you can't be hurt be starting with a new coil and see if that helps. If that doesn't help then, like chris said, start testing components for proper voltage. Auto parts stores loan out fuel pressure testers and most come with a multimeter, that is if your neighbor doesn't happen to have one.

 

Try the starting fluid again tomorrow. If it fires with fluid but not on it's own, sounds like fuel. at that point verify spark.
To quote a tv show - motors want to run.
3 things required timing, fuel mixture, spark.
Timing doesn't make sense if it will run ok sometimes.
Leaves fuel or spark.
You've gotta nail down which system it is for sure, then troubleshoot that system.