My name is mike i have a 1988 ford f250 v8 5.0, when i turn the key i can hear the eec relay click so i ran a few tests on it with a multimeters and all the test result came back good showing that i had a good ground and all the other wires gave of 10volts, so i moved on to the fp relay i had power and 10 volts to all of my wires except for wire number three which is the one that feeds power to the inertia switch than down to the fuel pump. i know my wiring is good because i havent jumped pins two and six together yet but with the newer relays they have 5 pins on them and if you take the wire on pin for which is hot all the time and plug it on pin five i can hear the fuel pump run. so my question is what would cause power not to come out of the relay even if the relay if good?

I know the relay is good because i took the fp relay of and put it in spot of the eec relay and i heard it click when i turned the key so i put it back on the fp spot. so my other question is are both relays supposed to click when you turn the key or is only the eec one supposed to click?

I will also post back in the morning after i jump pins two and six together/

 

Both relays are supposed to click when you turn the keyon and then the fuel pump relay is supposed drop back out one second later.

Sounds like you may have a bad EEC Computer.

To test ground pin #6 of the self-test connector and turn on the key. If the fuel pumps run then jumper pin #2 to pin #6 of the self-test connector and turn on the key.

If the pumps run with pin #6 grounded and not when pin #2 is shorted to pin #6 then you have a bad ground at the NEG post of the battery on the small black wire with a green stripe.

If the fuel pumps run both ways then pull the EEC Computer out and replace it or have it fixed. Open it up and see what the caps look like.



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So I guess I have a bad ground because when I jumped pins 2 and 6 together nothing happened but when I ground pin 6 the pump runs. what's the best way to fix the grounding issue?

 

At the NEG post of the battery there should be the Big cable and a small black one the runs to a single wire inline connector and then the wire turns black with a green stripe.

When someone replaces the battery cables the wire sometimes gets left off and then it cause the problem you are having.

Just look around the battery area for a loose wire.

This ground wire runs to pin #40 & #60 of the EEC Computer.

 

Okay thank you for all of your help I am going to have to look for that wire when I get up in the morning, because I was able to get it running by grounding wire six but the pump would consistently be running. So I know I'll needed it grounded the correct way so don't ruin the pump by it always being on.

 

It case you wanted to know the difference between just grounding pin #6 and shorting pin #2 to pin #6 here is a diagram showing how pin #2 is connected to the battery.

In the diagram below J1 is the large plug that plugs into the computer.
J1-40 & J1-60 go to the small ground wire at the NEG post of the battery and on newer trucks a ground point on the fender or radiator support and then they have a wire going to the NEG post of the battery.

J1-46 gos to pin #2 of the self-test connector and other sensor grounds.

Pin #6 of the self-test connector goes to the coil of the fuel pump relay and also runs to a Computers pin J1-22 so the computer can ground the coil of the fuel pump relay with chip Q11 and turn on the fuel pump using its pins 40 & 60 for the ground.





Old stile computer grounding:


Newer type of computer grounding:


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This will help out a lot I never really did electrical work till now so I was always lost when looking at wire diagrams, so your description will help me alot when I go out later to work on the truck after it stops raining.

 

Here is a diagram of the fuel system wiring on your 1988 F-series:


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Thank you I was able to get the wire grounded correctly my project truck is one step to being complete she runs like a champ now

 

Found it, thanks from people that do use the search function!!

 

Subford,
I have been reading your post and have been stumped on my issue. First off I respect all of your knowledge in these areas, thanks for sharing. I have been working on cars for about 25 or more years but electrical is my least experienced. I have a 1991 Ford F150, 4.9 with E40D, 2 Wheel Drive. I bought the truck for my son and the fuel pumps were bad (full of rust etc). I was about to put the new ones in and was about to splice new pump connection and realized there is no power to the pump (aft at this point). Long story short, I have power to the yellow wires to both the EEC and Fuel Pump Relays. I have constant power and good grounds to the Computer. I have checked them with my Power Probe.

I have already grounded Pin 6 and Pin 2 and 6 as suggested. Neither way I get any power out of the EEC or Fuel Pump Relays. I also have no Engine Light on when key is on. The only time I can get power to the inertia switch, then the Fuel Selector switch (both forward and aft tanks) is when I jumped the power too relay to the power out from relay. Then pump runs on aft.

This is what I have done this far (however to be clear issue existed prior to these repairs) I ran all new grounds from battery to starter solenoid then to starter and housing, also ran all new power cables from battery to starter solenoid etc. Cleaned ground lugs and frame bolt connections on ground to frame and by the battery negative (the small wires coming off of batter negative by radiator). I did all this because the cables were green and corroded etc. I also checked all fuses and changed ignition switch. New battery and charged to 12.9 volts. I also checked all fusible links by the starter relay, they are all good. I pulled computer out and it has a FSPF-12A650-SA on bar code but housing has E9AF-14A6387-AA and circuit board has a F4TF-14A608-DB. It looks brand new, no leaking capacitors etc. The date on the Computer is 03-30-96 which I thought was odd. But also odd that there are so many different numbers. Any way I plan on checking the computer info.,(actually checked it today and it comes up as a 1994 computer only so I am thinking its the wrong one someone put in there)

I am stumped and cannot figure out why I have no power. There is no clicking or anything either when I turn on ignition switch. I really do not know where to go from here. I have the Haynes Manual and original Ford Complete Wiring schematic as well. I would appreciate any leads. Thanks in advance.

 

Sounds like you problem is that the PCM (EEC) power relay is not picking when you turn the key to the run or start position.
Either the EEC power relay coil does not have a ground or it is not getting any power from the ignition switch.
The EEC Power relay must be picked before the fuel pump relay will pick.
Below is a 1990 diagram but yours should be the same.



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Thanks I appreciate the lead. I will check the grounds on the EEC relay too as you suggested. I did forget to mention that with key on I have no power to ignition coil (from what I remember on the later 90s you usually do but wasnt sure on the 91) but when I crank the truck with my power probe hooked to the coil supply wire it get 12.9 volts. So truck is turning over etc and trying to fire. I will check the ignition system today and at least make sure all wires are connected and have continuity etc. I will let you know.

Also, talked to Flag ship about my computer and they said the only one that is correct for the truck is a FLTF-12A650-ALA. So maybe thats the main issue since the one in there now is a FSPF-12A650-SA.

 

Make sure there is power going to the Power relays coil with the key on.
As far as power to the ignition coil it will only have power with the key in the start or run positions.

If you still have the Calibration sticker on the door post then post the Calibration number and we will tell you of the right computer for the truck.
There is no computers that have a letter in the second position of the number on the computer.

Attachment 277838
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Thanks again Subford. I see what you mean on the computer number. I checked the number again and that is the number on the one in the truck now (which I believe is not right). I have attached the Calibration Code below from the door and also the OEM computer number from the original Ford Schematics I have that shows the computer number as well. But that is the original one that is no longer available unless used. I have ordered a new one from Flag ship 1 that uses the VIN and they are sending me a F1TF-12A6520-ALA programed from my VIN.

On my ignition coil wire I do NOT have power with key on, only when i crank the truck and it starts turning over (but both coil wires test good with power probe). As far as power going to the Power Relays Coil with key on, do you mean the EEC and Fuel Pump Relays? If so, the only power I ever have to them at anytime is the yellow wires going to them which are hot with or without key on. No matter what i do with ignition etc. I never get any power coming out of the relays (which I understand is my issue but do not know why). It seems as you said either an ignition issue or a EEC issue.