I see that the wiring is different than earlier models.
Sorry if I have given bad information.

In this setup there is only one relay.
And power while cranking comes from the 'I' terminal of the starter solenoid and feeding the selector switch directly.

Fuse #18 wouldn't affect the pump power while cranking.

 

I really appreciate the help. Good idea I'll print it out and take it with me, good info!

 

I'm going to give it another try today. I've been reading some posts and have put together a kind of punch list before I drive across town. Maybe this will help others?

Thanks to ArdWrknTrk, subford, Gpedens, dustybumpers and others.

Step 1: Check the Fuel Pumps to see if they are working

Turn your key on but not to start and listen for the hum of the fuel pump from the tank. If you have 2 tanks you have three fuel pumps. One in each tank and one on the frame rail below the drive side door. You might have to get someone to turn the key while you hold your ear to the fuel tank. You can put your hand on the rail pump to feel if it comes on.

Step 2: Check in-line fuse links

Make sure all of the fuse links coming off the battery side of the starter solenoid are good.
To check them try to stretch them and if they stretch they are bad.
Check the small black wire with a green stripe ground wire coming off the NEG (-) post of the battery.
Check that the computer has a good ground. (no computer on a 1987 460? I need to confirm)

Step 3: Check Fuel Selector Switch and fuses

Check your fuses in the fuse box. This Truck has fuse 15 for tank selector and 18 for fuel pumps.

If the fuses have power and are good check your fuel tank selector switch on your dash. Pull it out and put a test light to the plug while it is still connected to the wires. You should have six wires ( 3 on the one side and 3 on the other ) the two center wires are your feed wires to the switch. One is for the gauge and the other is for the fuel pumps.

Your test light will be brightest on the source for the fuel pumps. Next check the one above and below the brighter center one and see if one of them have power. If not try switching the switch back and forth.

If you do not have power at the upper or lower terminals then you have a bad selector switch.

If one works but the other doesn't then one of your pumps is working but you still have a bad switch.

If there is no power to the switch in the center position then you will need to check for power from the fuses to the switch.


Step 4: Check the Fuel Pump Relays

The relays are located on the driver's fender near the air filter. The fuel is the green one, eec is the brown one. also check that the switch hasn't tripped it is on the inside fire wall, by the steering column, or behind the glove box area. You should be able to feel them click when you turn the key. They are about the size of an ice cube


I'm thinking it may be one of relays in this truck. Hopefully I can get this truck running soon.

 

The inertia switch inside the cab is a definite possibility.
But in your case you said you had no fuel while cranking.
So it may be an issue for others, but if I were you I'd look elsewhere.

I see your OP says 1987, and you mention pouring fuel into the carburetor, but you show a 1989 truck with EFI in your pic above.
I'm not sure which we're talking about.
No, there is no EEC computer for a 1987 460 over 8500# GVW.
These became fuel injected for the 1988 model year.

If you suspect the relay, look at the socket, and the bottom of it too.
It may just be a corroded contact or wire that is causing the problem.

In all, a good synopsis and I appreciate your effort!
Hopefully condensing all that information here will help the next person searching for a solution.
Rep's to you.

 

ardWrknTrk, sorry the truck in the photo above is just to show where the relays are located. i should have labeled it better.

I have found that there is no voltage to fuse 15. (auxillary fuel tank selector)

So i'm thinking that the aux tank relay is bad.

I wish i could post photos from here. Im off to the parts store . . .

 

Also the connections looked good on the relays. I may just replace both.

 

Here is the beast.



Relays for fuel pumps and Auxilliary Fuel Tank Selectorl




Local parts store had one relay (part# BWD R647)

I had to order the other one (Part# BWD R3239) I think this one is for the Aux Fuel selector.

I'm hoping this is the problem. Now waiting on parts . . .

 

You said there is no power TO fuse #15.
Did you find there is power in the fuse panel?
Those fuses you can test at the top with a pinpoint probe on either side of the element.

 

Thanks, yes the panel had power. Fuse 18 location had power. But fuse 15 location had nothing. I tested both 15 & 18 panel locations without the fuse installed. I also tested #18 and some of the other fuse locations with the pinpoint probe with the fuses installed thru the top fuse contacts.

I'm hoping that O'Reilly Auto parts cross referenced the gray relay correctly. It had no markings or part numbers. Autozone and Napa also said the part was special order.

If anyone in here knows the correct part numbers on the relays it would sure be a big help.

Thanks again !

 

I'd check fuse links and all the pins of the plug to the ignition switch if you weren't getting power to sections of the fuse panel.
Maybe drop the fuse panel and see how the bus is routed on the back side?

The '84-'86 460 selector relay is E3TZ-13A025-A
Not sure how that changed, but Subford cites a '86 diagram as accurate for 1987.

 

Good idea, thanks. I'll make sure I do that when I'm at my friends house next.
Maybe one of the wires where the ignition switch plugs in isn't seated properly. A few of those wires were loose before I reseated them.

The truck started fine before I did the ignition actuator repair. I'm thinking that the problem is something that I caused. So the ignition switch was moved around and the wires were loose. I thought I got them back in place. Also the key was left on which maybe damaged the relay?

 

I don't think leaving the relay energized hurt anything.
After all, it is energized every second you are driving the truck.

 

You are right ArdWrknTrk, the relays were most likely not damaged. I wasn't thinkin. I should have checked for voltage there first.

I'm back at it again. So far I've checked Some things.

There is voltage at fuse location #15. (i wasn't testing it with a good ground previuosly)

All fuses and locations in the pannel were tested. All good.

Ignition switch plug wires are seated correctly. Switch is new.

The fuel pumps are not turning on with the key in the on position.

The fuse links from the battery side of the starter solenoid seem to be good.

The tank selector switch isn't getting any power. (i tested it with a multi meter and test light)

There is voltage at the two fuel relays (one has power to the yellow wire, one has power on the black white stripe wire) but relays are not turning on with the key in the on position.
Fuel relays are new.

I'm not sure what to do next.

 

Thanks for your help ArdWrknTrk!

I appreciate your time and effort to try to help me.

I have a 2000 F350 7.3L diesel and am not that familiar yet with the OBS 7.5L 460

I too was trying to help when my friend had a broken ignition actuator arm. A 3 hour repair job has turned into a weeks worth of time and it still doesn't run.

I was a bit surprised that I didn't get help from any others on this site as I'm sure there are some super mechanics in here that know the 1987 F250. I'm not sure why, maybe this site is too big and the posts fly by so fast? At powerstrokenation.com were I hang out things are a bit different.

I have ordered a 1987 F250 complete wiring diagram and I will run down the problem until I get the beast running again. When I figure it out I'll post the fix for the next guy.

 

There will only be power in 'run' if the engine is running and the oil pressure switch is closed.
With the key in 'run' and the engine off it's simple enough to jumper the oil pressure switch at the back of the engine (below the EGR valve), and see if you then have power at the red/yellow wire of the fuel pump relay.
That will pull the relay closed.
If you have selector switch power with the key in 'start' and not in 'run', it could be a burnt resistor wire, or a bad oil pressure switch.
If you have power at the relay socket yellow wire and want to test the pump/selector/switch, jumper yellow to pink/black at the socket.
That should energize the switch/selector/pump(s) if the resistor wire is good.

In looking at the schematic Subford posted it seems the only reason you wouldn't have power to the tank selector switch in both 'start' and 'run' is if the pink/black wire were open.





As with any 'blind' electrical troubleshooting it is always easier to start 'upstream' and work your way to the fault.
If you're a mechanic with experience of a particular vehicle you would know which component is likely to have failed.

I'm not a good mechanic. I don't even have this system in my truck.
Anything I know is because I've BTDT.
But I can easily visualize the schematic and figure out where the problem lies.