Fuel issue HELP
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Fuel issue HELP
Okay, so I am new here, but registered to get some help. My 87 F150 4.9 (4 speed 4x4) has been giving me a lot of trouble recently. It has 94k original miles on it. I recently replaced the distributor because my truck died and had no spark. I noticed some driving to work, (10 miles) that it hesitated twice, but ran fine. Anyways long story short it died again, this time no fuel. I checked the relay, and it seems to be good. Today I dropped my tank and replaced the fuel pump which sucked lol. Got it all back together and whaddya know, truck cranks but no start at all. I do not know what to do next, but I am getting no fuel to the rail and cannot hear any kind of fuel pump running when I turn the key. Makes me think maybe wiring or something? The inline fuel pump was replaced about a year ago so I don't think its that, but couldn't get a signal from my test light on any wire under my truck. Anyone have some suggestions???
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Awesome, thank you. Gotta love the forum. Should have joined sooner lol. Earlier this week I was looking at fuses under my dash, and I did come across something that looked like that, just no red button on top. It had a sticker over a little hole that said "reset". I stuck a screwdriver in it but didkt feel anything happen. Do you have to hold the button down? Thanks for the help btw, I seriously appreciate it.
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Update, so i found the inertia switch, turns out the previous owner had unplugged it, so it hasn't ever been hooked up since I have owned it. Along with the clutch interlock switch and door buzzers. I couldn't even find the connection to plug the inertia switch back in. But since I have been driving it for 3 or 4 years without it, I don't think that would be the problem. Any ideas on how to test the ecc or eec relay that's right next to the fuel pump relay? I am not seasoned in understanding those diagrams printed on them. I just vaguely get it. But not sure which pins to check. Also, does somebody have a schematic for an 87 f150's fuel system?
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From: Vernon, BC
Take the relay for the horn and use it in place of the fuel pump relay. If you get the pump to prime when you turn the key on then you know the relay was bad. I had to carry several relays I picked up from the JY and change the EEC relay whenever my truck wouldn't crank to start. Simply swapping in another one got it to go. Cheap and easy to test that way.
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Okay so I bought a new EEC relay, and now I can hear my fuel pumps working. So that was good, truck acts like it may start but just won't, 
I've primed it tons of times trying to get fuel built up because I also installed a new fuel filter with the new fuel pump. Any reason why I still won't start even tho it sounds like fuel is getting to the engine? The pump does sound kind of weird tho, not sure what is up with that
I've primed it tons of times trying to get fuel built up because I also installed a new fuel filter with the new fuel pump. Any reason why I still won't start even tho it sounds like fuel is getting to the engine? The pump does sound kind of weird tho, not sure what is up with that
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From: Vernon, BC
Now that you know the pump is working, the next step is to check the fuel pressure at the fuel rail. I'm not sure what the fuel pressure should be for an 87 4.9 engine so you will have to look it up. I think it should be something like 45 lbs. However, four or five pounds difference either way can make all the difference in the world when trying to start your truck. If you have correct pressure then your issue is something else. Spark or injector function probably. If you have low pressure then either your low pressure pump (I think they called them lift pumps?) or the high pressure pump is not working as they should. Someone else will have to give you the test procedures for them as I don't know what they are.
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Going to work on it some more today, I will have to pick up a fuel pressure gauge as well. Given that I just replaced the in tank pump, means it may just be the high pressure in line pump. Or maybe injectors like you said. Something weird tho, when I checked my fuel lines again to make sure I had them hooked up right, I unhooked them from the new in tank pump, but they were completely dry... no fuel came squirting out like it did when I changed the fuel filter, or the lines on the old pump. I put at least 7 or 8 gallons back in my tank, which should definitely be enough to get sucked up by the pump. I'm starting to think maybe the high pressure pump is the culprit. Even tho I did replace it about a year or 2 ago. 
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Update, truck runs!
So I got the truck fixed, turns out the people at the parts store gave me the rear fuel pump even though I asked for the front tank pump... 
. But now it is running so I am super happy thank you all for the help! Cheers! 
. But now it is running so I am super happy thank you all for the help! Cheers!
Fleet Owner
Joined: Oct 2005
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From: Kentucky
Glad to see you got it running.
If the fuel pump(s) are working with the inertia switch unplugged it's obvious someone has wired around it. That is a HUGE safety hazard IMHO. If it were mine I would wire it back in.
If the fuel pump(s) are working with the inertia switch unplugged it's obvious someone has wired around it. That is a HUGE safety hazard IMHO. If it were mine I would wire it back in.
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