hi everyone,

i am chasing down things in this truck i scored.
i want to get it starting and operating properly before i start "other repairs".
so here is where im at, it starts when it wants to. ive narrowed it down to fuel, when i rapidly flip the battery disconnect with the key on until i hear the fuel pump cycle then it will start.

so my question is does anyone know if the wiring between a 2002 and a 1999 is the same, for the fuel pump ONLY.

i have a wiring diagram book for 2002 and hoping i can reference that until i get the 99 book ordered.

and since its not in my Sig yet it is a 1999 f250 C.C. L.B. 4x4 v10 auto

thanks in advance Dave

 

68 views and nothing ??

 

I do t have an answer to your question , but I can tell you , from my own experience , as I also own a 99 V10 5 speed .
It sounds like you can just replace the fuel pump and be done with that part of your list.
I bought mine from Amazon, I have prime membership , and the pump is an Airtec , and was 58.00 .
My original pump had a date stamp of January 16 1999 , and the truck was assembled in February .
.

 

I don't think they are exactly the same. The ground on the 02 goes through the ECM and is timed. IOW, you turn the key and the pump primes, then shuts off until you start the truck. I seem to remember someone saying that the 99s stayed on as long as the key was on. I could be mistaken though.

 

the 99 should have a an extra relay that removes the ground going to the fuel pump depending on vehicle over speed, other wise the same as 02 with PCM controlled positive from a relay through the inertia switch.
you can hook up a test light to the + and - for the pump at the tank then cycle the key. It should light up for a moment but not stay on every time you cycle the key.

 

See im all about replacing the pump once i verify it is actually the pump.

there was so much jury rigging of rigging of the wiring on this thing that i need to square that all up before i replace parts

 

great info, any idea where the said speed relay is located?
if i have this i can remove it and jump from 30 to 87 to be sure i have a ground

it currently pulses only sometimes, and when it doesn't that's when it wont start

 

power distribution box under hood
labeled "fuel pump speed relay"
counting from the diodes its the fourth one
also I made an error speed relay removes the ground when activated, the circuit is connected 30 to 87a then when over speed occurs the relay energizes it removes pin 87a from pin 30

 

Understood on speed relay. Is the 5th one back the power relay then?

 

The pump does not care about anything but 12v+ and a ground .
Mine comes on for the required 2-3 seconds to prime the system, just like any other Ford with EFI.
With out a helper , you are most likely not be able to see the signal (test light) with out a very long lead .
The fuel pump and sending unit harness is right above the tank , and I would say , since I just had mine a part ,that you can at least , with a helper , using a test light , verify you are getting the signal to the pump , in less than the time it takes to drink a beer , or smoke .

 

To your point, maybe just the fuel pump relay. They don't go bad very often but flipping on a disconnect may active it for enough time to start you up.

 

That's just it, it gets power when it feels like it. That's why I need the proper layout for this truck to properly diagnose the issue

 

New relay on the power side, I'm going to manually bypass both relays ensuring power and ground and see if it is consistent after that. If so to me eliminates the pump and points to the control side of the circuit

 

Hopefully fellow member ProjectSHO89 chimes in as he seams to be a wiss at wiring and schematics.

 

Kaz has nailed down a diagram for me on this.

And once I'm done with that white stuff we got last night I'll pick it apart a little.

But if anyone else jumps in with known issues I'm all for it.