96 ford f150 wont start!
 

Hi everyone! I need to make a 12 hour trip this weekend and everyone is stumped about my truck! It is a 96 ford f150, 5.0 V8. It was dying at stop signs, but driving fine otherwise, and sometimes I had to pump the gas pedal to get it started. My dad took it to work with him and the mechanic at the university put the diagnostic machine on it and it pulled that it needed a purge control valve (im pretty sure thats what it was called). He cleared the code but about 20 miles later it came back on, but was driving fine. My dad washed it and washed the engine with a hose (i dont know why!) and 3 days later it wouldnt start. Took it to the dealership and they got it to start, and replaced the purge control valve. I picked it up and it started fine and drove around town fine, I drove it home and a few minutes later my dad tried to start it to drive it into the garage, and it took 3 tries to start. I drove it later and it started fine for me each time. Had my uncle come over and it started fine for him, drove around and the check engine light came back on and still pulled the same code for purge control. He tried to start it again and it would not start. He tried multiple times to start it. He unhooked the mass air flow and temp sensor and it started right up. Plugged them back in, and it still started. We dont know if this is because he unhooked them, or because the engine had time to cool off. I'm sorry for the huge explanation, but I was trying to be as detailed as possible! Oh and the dealerwship mechanic I cannot trust at all, they say they pulled 6 codes, a total of 1900 dollars (on a truck that blue books for 2400!) and to change the spark plugs and wires, they wanted 800 dollars!!!!

Unhook the battery for a bit, then hook it all back up and see how that works. Should erase those codes and give the engine a chance to "reboot" and see what is currently wrong.

Hows the fuel pressure? Have you replaced the fuel filter lately. Does it idle in Park/Neutral? I'd think not the way you describe.

you mentioned they pulled six codes, just curious, are you still getting six codes or just the purge valve one, what are the other codes. sometimes it might be just one thing that will throw off two or more things

I have already unhooked the battery for about an hour and reconnected it, before I took it to the dealership. It still wouldn't start for me, just whine and whine. Now when I start it it doesn't just whine, you can hear the engine try to start, but it won't. Before there was no engine noise at all, just the whining, but I think that's because my dad got the engine all wet. Yes, my dad just replaced the fuel filter, the fuel pressure is fine I think because it drives fine? It just won't start now after its been driven and its still hot. I haven't tried to idle it in neutral, but when it does start, it idles in park, it might be idling a little high but I might be imagining it by trying to listen for something.

What do you mean "whine"? So when its hot, it'll crank but wont start?

When my uncle came over with his code reader he still only got the purge code. The dealership said: RPM code, lean code, purge code, trans fluid sensor code, oxygen sensor, pcv, stator, spark plugs/wires, decarb.

yes, when it is hot it will crank and whine. The first time it ONLY whined, no engine noise, all the other times, it whined, and the engine made noise like it was going to start, but only for a few seconds. (I'm really sorry I don't know all the right words to describe these things... if you can't tell, I'm a girl! Lol!)

Well I was gonna say maybe the ECU got fried into limp mode or something, but it usually causes the truck to run rich, not lean.

The O2 sensor, the RPM (idle control valve), and running lean codes could all cause it to stall out or run bad all by themselves, let alone all together.

when you say "whine" could it be a hissing, like a vacuum leak? If so, get a can of carb/TB spray and spray it around under the hood while idling/running to see where you get a reaction. then check that area and you should find a vacuum leak.

by "whine" i mean the starter noise, like before the "vroom". I'm pretty sure the o2 sensor is okay, I think the guy at my dads work checked that.

I've been searching alot online, could it be a pip sensor or tfi module?

The TFI (ICM) Black module very seldom goes bad.
Could be the PIP sensor (RPM code) though.
When you get that many different codes it turns out most of the time to be the PCM computer itself is bad.

Usually when you see alot of codes that are not related and you didn't cause them by unplugging sensors etc it can be the ECM.

The best way to figure it out is some basics..Check all grounds for being loose. Battery, ecm.. when it wont start do you have spark? Is your distributor now dry? It could be an intermittant problem with the module (sometimes mounted on distributor or driverside fenderwell.

Check for spark - put a spare spark plug in a wire and check for spark at no start situation. If you have spark then move on.

Attach a fuel pressure gauge and wait for it to not start and look at pressure. If you have no pressure or below spec. it could be your issue. you could also try a squirt of carb cleaner but suspect its not fuel as you said once it runs it has decent power correct?

Check your collision switch. Usually on center hump at base of dash. If the switch is going it can cut power to the fuel pump and you wont start it..

Try some of that first..

It has spark, and it is getting fuel, my uncle did something that he checked while I turned the key and fuel squirted out. The distributor is now dry, and it only wont start when it is hot from being driven. I think they pulled all those codes initially while they were trying to start it at the dealership, and cranking the key/pumping gas, so it threw a bunch of codes all at once. I wasn't there, though, so I don't know if thats how it went.

Hot start makes me think something is a foul with the pickup or module. The pickup is magnetic and if it had a crack it could spread enough but I would think if that were the case it would stall hot too.

Have you tried unplugging the mass air again? If you unplug it and it immediatly starts it may be related but if it takes several tries it might just be coincidence.

We tried again and it wouldnt start, unplugged mass air flow and the other part and it started and idled for 5 seconds, then died, and wont start at all now, just sputters. This is the other part we unplugged, anyone know what it is? its on the drivers side near the mass air flow. http://i24.photobucket.com/albums/c5...3/9aca370a.jpg

That is the your Intake Air Temp Sensor (IAT).

I'm trying to find it on oreillys website, is there something else it might be listed under?

Here is a link:
BWD WT385 - Air Charge Temperature Sensor | O'Reilly Auto Parts

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Update - still wont start! Still pulling code for purge control valve even after we replaced it. Replaced air charge temperature sensor and engine coolant temperature sensor. No change. Starts when cool, and drives fine, wont start when hot. After it's gotten hot, have to hold the gas pedal to the floor to get it to start again when cool. Since I couldn't describe it very well I took a video so you can hear the sound it makes:

YouTube - ‪1996 ford f150‬‏

Sounds like a fuel problem.
Have you changed the fuel filter?
Tried the other fuel tank?
You need to put a fuel gauge on it and see what you get.

If you get really desperate, try this...

Unhook the exhaust pipes from the headers and then try firing it up.

Make sure to keep any electrical wires away from the outlet on the headers. My truck was doing the same thing back around Christmas and we were stumped for almost a month and literally tore the engine apart and built it back up with new parts gaskets etc.... turns out the catalytic converter was so plugged that the back pressure was causing the engine to whine and not start like you describe. Give it a shot... like i said; when you get desperate.

Same deal.
 

Im having the same problem, starts great first thing in the morning, but after running for awhile it sounds the same as your video.

I have replaced the fuel pump, fuel pressure seems fine. Looks like alot of people have this problem with 150's from this era. I'll be following along and update if I figure anything out...