Can someone help? I have a 1987 F150 extended cab with 5.0 EFI engine. Auto tranny. Here's what I do know. It is fuel related. Here's how it began:
First I used to hear the relays and then the fuel pump charge at every start. I no longer hear the pump charge up, and line doesn't seem to pressurize.

How it began: I was exiting highway and truck started acting like it was running out of gas. I quickly switched tanks to no avail. It was still idleing very low and only as long as I was feathering the gas pedal. It died and I've only been able to get it started once since then, after replacing the fuel filter, and it only ran short time at low idle with me feathering the pedal again. No start since.

Here's what I've tried: I replaced the fuel filter, tried different relays, and replaced fuel pump that is located on the rail. I also cleaned battery terminals and wires real good.

I've been told that there are low pressure pumps in each tank, but I really don't suspect them as it would be odd for both tanks to give up the ghost at the same time. I guess?

I'm no expert mechanic, but I can fix problems, once it is diagnosed. I'm just not real good at the diagnosing part. Doht!!!

 

So, you have replaced the pump on the rail and the fuel pump relays but you still can`t hear the pump running? I am no expert either but I would think you are going to have to check for voltage at the relays and pump. Just a thought but could the inertia switch need reset? I don`t know where it is on your truck. This should give your post a bump.

 

Hi LazyK. I can hear the relays click and while under the truck I can hear a slight hum from fuel pump, but it isn't loud like it once was. I'm about to check the fusible links over by the starter solenoid with a test light. I read one of those should be connected with fuel system in some way, and could possibly have gone bad cutting power in some way.

Oh...Yes I checked the inertia switch and it seems to be working alright. (I took it out and would set it, then give it a quick shake and it would kick out every time)

 

pretty sure the inertia switch is by the brake pedal in this year.

 

DANG!!!

I think I just commited the cardinal sin of shade tree mechanics 101.
I used starting fluid and it would run on it until gone. I was about to go get a battery for my test light to check the fusible links out, when my wife came out to see if she could help me out. I said " Sure. Get in and crank it." She asked if she should hold the gas pedal down and I said "sure, we'll see if that helps." I sprayed more fluid into breather tube then told her to crank it. Well that's when things got CRAZY! It blew back into air filter box.
An M-80 couldn't have blown that box apart any better. Pieces went everywhere! I'm lucky it didn't take my head off. I'm not worried about the filter box as they are cheap enough at the junk yard, but is it possible that I may have caused internal damage?

 

Unlucky about the airbox but everything else should be OK. At least the ether shows that you have spark of some sort. When was the last time you changed the plugs and wires? Have you got a voltmeter? You could check for 12V at the fuel pump. Is there any way you could check the fuel pressure at the engine? Have you tried pulling error codes? If so did you get any? If the pickup coil in the distributor is faulty the injectors will not fire, but I would think that would throw a code.

 

where's the map sensor located? What's it look like?

 

WooHoo! It's fixed. It turns out it was the crossover switch.
Thx everybody