I replaced both battery cables yesterday with side post cables. Now, the truck turns over, but will not start. After checking my connections and trying again, still turns over but doesn't even sound like it wants to start.

So I started checking things and found that when I turn the switch on, the fuel pump doesn't come on like it used to. I have the front up on ramps. I checked and I think I reset the fuel pump inertia switch under the dash, but that had no effect.

Any ideas what I should check next? I didn't intentionally unplug anything. As far as I know I hooked everything up the way it was before.

It's an 87 F150, 4.9l, fuel injected, with dual tanks.

Any help will be appreciated.

Thanks,

Chris

 

Did you reconnect the 2 ground wires that come in from the wiring to the neg terminal? These are located right by the battery on the core support. Other wise, check to make sure if you changed the whole cable,and not the ends,that you have all the wires that go on the bat post of the sol,connected.

 

I know this might sound dumb, but have you checked the fuel pump fuse? sometimes it's the easiest stuff...

 

I second that suggestion.

 

Thanks for the replies. I did connect the 2 ground wires. I put connectors on them so they connect to the side post just like the cable. Just an FYI, I tried starting it without the 2 ground wires connected and there was no noticable difference. I did check the connections to the solenoid and there are 3 wires plus the cable to the battery and they are all connected. I did think of the fuse and was unable to get the one that I think controls the pump out (seems like it was #15 or maybe that was the amps). I will give the fuse another shot tonight.

Thanks again for the suggestions. I will keep you posted.

CHris

 

You do not have a fuse for the fuel pump.
You have a fuse link that bolts on to the starter solenoid on the battery side.
You may have left this fuse link disconnected.
Check to make sure all of the fuse links are bolted on the battery side of the starter solenoid.

 

Subford, Thanks for the reply. Based on the fuse diagram, there are 2 fuses that remotely refer fuel. #15 appears to have something to do with the tank selector switch and #18 appears to have something to do with fuel pumps but may be applicable to the 7.2l engine. Regardless, they both appear to be good.

I'm not all that mechanical so let me make sure the solenoid is what I think it is. Does the positive battery cable connect to the solendoid (mounted to the passenger fender) and the battery? If so, there are 3 wires, each with a round connector, to connect to the post along with the positive battery cable. They are all connected. I don't know anything about a fusable link. Can they go bad? If so, how do I test?

TIA,

Chris

 

To test a fuse link you try to pull it apart and if it stretches it is bad.
Those fuses are not used on your truck or at least for the fuel system.
Yes the positive battery cable connect to the solenoid (mounted to the passenger fender) and the battery.

Here is a diagram for a 1986 I think the 1987 is the same:


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Bill's right (as usual) there is no fuse for the fuel pumps. I would bet that you blew the fusible link. You'll find it a few inches off the start solenoid in one of the wire bundles that connect to it.

 

Thanks guys, I really appreciate the help. I will start checking them out this evening and keep you posted.

 

Here's an update so far.

In looking at the wires coming off the solenoid, there are 3 loop connectors plus the positive battery cable. Obviously 1 is the positive battery cable. Another 1 goes to the altenator so I'm not looking at it. That leaves 2 loop connectors, both have 2 wires connected to it. 1 of the has blue and brown wires. The blue one runs into a yellow wire with a fusible link thing that says 20 ga. The brown one runs into a yellow wire with a fusible link thing that says 18 ga. The other connector has a black and green wire. The black one runs into a heavy yellow wire with a fusible link thing that says 14 ga. The green wire runs into a black wire with a yellow stripe with a fusible link thing that says 16 ga.

I have tested all of these wires with a circuit tester (one end connected to ground post on the battery and the other end is a sharp probe that will penetrate the wire insulation). All of the wires indicate they have power downstream from the fusible link thing. All of these wires run into a big bunch of wires that run across the front of the truck to the drivers side fender and end up close to the firewall. I probed all of the yellow wires there and seem to have power to this point.

I don't know if what I am doing is right or not, but this is what I have done so far. Tried to check the inertia switch for power, by disconnecting on probing into the connector, but didn't get an indicator that there was power there. Not sure if I was doing it right or not. Did I mention I still have the truck up on some ramps. Wouldn't think that would have any impact, but what do I know.

I tried to pull the red wire off the full pump on the frame rail under the driver's seat, but couldn't get it off. I was afraid to tug to hard on it as I don't want to make matters worse.

So this is what I have been doing today. I'll have a buddy take a look later in the week just to get an extra set of eyes on it.

Any further suggestions?

Thanks,

Chris

 

I think what you have done is leave the EEC Computer Ground wire off on the NEG post of the battery.
This has a small black wire coming off the NEG post connector to a one wire in-line connector and then from there it is a black wire with a green stripe.
Without this wire the engine will not run.

 

Thanks for the quick reply Bill. The original NEG battery cable had 2 wires incorporated into it. Both of the wires are black with no stripes and have in-line connectors. I cut the wires and put loop connectors on them and now have them attached to the NEG side post on the battery. I tried starting the truck without them connected to NEG side of the battery and it didn't have any impact. Truck would turn over, but the fuel pump wasn't coming on.

I'm not sure how to post pics here so I sent them you your g-mail acct. One shows the 2 sets of wires I described in my last post. The other shows the 2 wires with the in-line connectors that I described above.

Again, I really appreciate your willingness to help. I really want to learn how to work on my on vehicles, but it becomes very difficult when you run into things like this and don't really have a clue what to look for. I thought I was doing pretty good when I picked up on the fact that the fuel pump wasn't coming on.

chris

 

OK, short pin #6 of the EEC self-test plug to pin#2 of the EEC self-test plug with the key on.
Does the fuel pump relay click as you short the two pins and again when you remove the short?



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I know where you're going Subford about 5 yrs. ago I was plagued with the same thing, rather embarrassing when you go to light em up at the the work place, and the truck suddenly dies. :-( turned out to be a relay in that area. :-)