I have a 1987 F-150 XLT 5.0 V8. About a week ago I pulled it into my garage, and everything was running just fine. I went out to start it up the other day, however, and the engine wouldn't turn over. At first I thought I was out of gas because my fuel guages have not worked in years. I added about 2 gallons of gas, and still it would not start. By this point, my battery was dying, so I took that down to the auto parts store and had them recharge it. I brought it back, installed it, and when I turned the ignition the starter ran just fine.

I am now suspicious that my fuel pump is shot. I want to verify this first, though, and I'm hoping someone can help me diagnose the symptoms. First, I used to hear a hum from beneath the truck (I assume the fuel pump) whenever I turned the ignition slightly forward. That sound now seems to be gone. I assume this means the pump is not activating...is that correct? I figure there are two reasons for that. One, the pump is busted. Two, it's not getting voltage from the battery (relay is dead). However, I do still hear the familiar clicking noises under my hood when I turn the ignition slightly forward. I assume these are the relays clicking away. So, I'm really starting to believe the fuel pump is the problem. I'm thinking about disconnecting the electrical leads from it and attaching a multimeter to see if voltage is reaching it when I turn the ignition. If I read a voltage, is it safe to say the fuel pump is shot? I don't think my model has a reset button, but I could be wrong.

Any help or advice would be greatly appreciated!

 

I think it's your pump, I think you have as many as 3 pumps ... one in each tank if you have two and one on the frame rail, but hopefully someone with an 87 will clear that up.

 

Yes the truck would have 3 pumps, two low pressure pumps(one for each tank) and the high pressure pump located under the drivers seat on the driver side frame rail. And yes your diagnosis with the voltmeter will tell you that the pump is shot. The fuel pump interia switch, which your truck has(i have no idea where though), kills the voltage to the pump. So if you have volts at the pump, and it doesnt run, then the pump has failed.

 

The fuel pump interia switch, should be inside the cab on the firewall, right next to your e-brake pedal. There should be two relays(one for your fuel pump and i can't remember what there other is for) they are identical and you can switch them to see if one is not working correctly. But, its most likely your fuel pump. I had the same problem where it would run fine for a while, then not start and the next day be fine again.

 

The other relay is the EEC relay. I dont recomend switching these two relays to try and diagnose the problem, since if it is a relay then your truck will not start since you just moved the bad relay to the computer circuit. For the price of a relay, buy another one and have it for diagnosis problems if it turns out that it wasnt a relay to begin with.

 

First, thank you all for your help! Ya'll are correct, there are three pumps. I forgot about the ones in the tanks themselves.

I've got some more information I'd like to bounce off ya'll to further narrow down the problem. My truck still is not starting. If the battery is charged and I turn the ignition, the starter turns like champ. Does this rule out the ignition coil? I checked my distributor, rotor, etc. and it all looked ok. Is there anything else electrical that is notorious for making a truck completely fail to start? Are there any tricks I can use to rule out an electrical problem?

My truck has two fuel tanks (like many of yours probably do as well). I haven't used the front tank in a long time, but when I switch over to it and turn the ignition, I can here the whirl of the fuel pump from what I believe is the front tank. I do not hear anything when I have it switched to the back tank. The truck still is not starting on the front tank, however. So this leads me to a couple of key questions,

1. Should the in-line pump (the high pressure one under the driver's side) make noise too when I turn the ignition? Or, is it typically quiet? Does it make noise on your trucks? I have a '97 F-150 too, and I've been listening on that, but I can't really tell. If this pump failing alone cause the truck not to start?

2. How many clicks should I be hearing under the hood when I turn the ignition? I hear two. One occurs when the fuel pump in the front tank shuts off. The other occurs as the Check Engine light shuts off.

Also, ya'll are right about the reset/inertia switch. I found it under the instrument panel. It looks like it's ok.

 

I have a 90 so I may not be able to answer the low and high pressure pump question, but I am sure that if the high pressure has failed not enough fuel will enter the combustion chamber through the injectors if the pressure is not enough. I would check the ignition by removing one wire at the plug and either removing one plug or getting one hanging around your garage and ground the body of it on your vehicle holding it with a good insulated pliers. Have someone crank her over and see if it is sparking. If not then troubleshoot the ignition, if it is then troubleshoot fuel. It could be an ignition module in the distributor ... the most time look good when they fail. I have seen a few really burnt.

 

Get a fuel pressure gauge and check for fuel pressure at the fuel rails on the manifold. They are not exspensive and can even be rented at some parts stores. Checking for spark, like silversport has said, is also a good idea. Make sure you check it at a plug, and also at the coil. If you have spark at the coil but not at the plug, look at the distributor cap and rotor. There should be a center electrode in the distributor cap. I have had them burn up and/or fall out. If you have it at a spark plug then spark is not the propblem. The frame rail pump should make the similar wiring noise. Under the hood the two clicks are normal since you have two relays that function in the starting sequence, one to turn the computer on, and one to run the fuel pumps. The 97 ford that you have has only one or two pumps, depending on how many tanks it has. These pumps are located in the tank and do the jobs of the combination pumps in your older ford. Definetly check fuel pressure on the manifold to asses whether it is fuel or not.

 

It sounds to me like the high pressure pump has died. I would check it with the voltmeter and go from there. If you can't hear it when you turn the key to run, then I will save you a trip to the parts store for a pressure gauge and tell you it's zero.

 

Guys, again, I cannot thank you all enough for your continued assistance. After reading everything carefully, I've decided to start by performing the spark test (to rule out an ignition problem) and checking the leads to the in-line pump with a voltmeter. If both check out, I will probably go ahead and replace the pump.

A couple more questions. From your experiences, what is the safest way to perform the spark (plug) test? My dad had me gap and replace all the plugs on this truck when I was a kid, but I've never actually cranked the ignition with one dangling freely under the hood. Is it safe to just hold the shielded spark plug wire with gloves? Should I use insulated pliars? Also, do I need to ground the body of the plug on the block, or will it spark just dangling in the air? It makes sense to me that it probably needs to be grounded. There's only one lead (the spark plug wire) going to it.

Also, does anyone know how to get the cylindrical, metal housing off from around the in-line pump? Or, does it just slide in? I know it has that rubber jacket wrapped around it, but it's been sitting there for 20 yrs. That sucker refuses to budge. I'm trying not to take a hammer to it in case it's not the problem.

 

The best way and safest was is to take an insulated phillips screw driver and push it into the end of the plug wire and hold close to the block and crank the engine. DO NOT HOLD THE WIRE WITH YOUR HANDS OR GLOVES (it doesnt feel nice). Do the same for the coil wire using the end that plugs into the distributor. If you have spark there and at a plug then ignition is not your problem. Good luck, and if you get shocked it wont kill you or hurt you, but man does it hurt.

 

I know it has been a while since my last post. Progress has been slow since I have been working on this piecemeal as I find time outside of my job. Nonetheless, I've completed both tests. I do have spark at the plugs, so I think it's safe to rule out an ignition problem. I am also measuring 12 VDC at the in-line pump when turning the ignition to run. I can hear the pump in the front tank whirrring when I turn the ignition, so I'm thinking the problem has to be that in-line pump. I'm ordering a new one tomorrow, and I'm going to replace that, along with the fuel filter.

Is there anything else I should check? I doubt the injectors would be the problem. It's unlikely they would all just completely quit working at the same time. Is there anything else in the fuel system that might be a problem?

 

If you are saying that the pump in the tank runs all the time and you have 12 Volts on the wires to in-line at all times then I would say the EEC Computer is bad.

You should have power for one second when you turn on the key and then there should be none until the engine starts cranking/running.

 

Take off the inline pump and test it on the bench with a battery and a couple of hoses. Make sure you have cleaned the outside of the pump from all gas before testing it on the bench so as to not start a fire if it arks. If the pump isnt making noise, even when you are right next to it and it is installed in the truck, then change that before you start blaming exspensive parts like computers.

 

I have an '87 F150 300 I6. I had this same problem. The truck would turn over like a champ until the battery died, but the truck would not start. Also sometimes it would start, but then it would die whenever it felt like it and would not restart until it felt like it.

I found the problem to be the wire running from the fuel pump relay to the pump itself. It was broke off at the relay and just barely touching the relay connector. So When I turned the key, I would hear the relay click but I would hear nothing from the pump. I actually found the problem on accident, by tapping the relay after I got the truck started. When I tapped the relay the truck died and would not start again until I tapped on the thing some more.

Anyway, I cut away the protective plastic sleeve that covers the electrical connections, and proceeded to solder all of the wires to the relay. (I tried to buy a relay at the local "advance auto" but they could not find the right one.)

I have had no more problems since I soldered the wires.

Good luck!