I have a 88 f 250 with a 460. I believe a the engine is throwing a code that is disabling my fuel system. Killing power to fuel pump and injectors for sure, maybe more. If the enginge cools and ya unplug battery it will start, run for bout 2 min then kill itself. Any ideas on the cause? Currently I am unable to pull codes due to the STI connection in not to be found. Any help would be great.

Thanks Mike

 

Do you have spark through the spark plug wires when it dies? I would guess one of the ignition components is going dead cutting off power to the injectors. Just a guess though.

 

do u have dual tanks if so check the switch connection that will cause the fuel pumps not to turn on

 

Yes it has dual tanks. Switch seem to be fine and it does have spark it seems to only affect fuel system.

 

You can't find the EEC Test port?

 

I had a bad ignition module once before on a different make and model of vehicle that caused the engine to die after a few minutes. It can't be all that different from make to make.

Tim

 

ign modoule. hmmm.... I can find the eec port not the STI small lil plug in.

 

isnt the eec test port under the master cilyder on the fender

 

If you can find the EEC test port then you can find the single wire pigtail. They come out of the same loom. It's probably just buried under something else. You need to pull the entire loom up and look at it. There is no code in the computer that will turn off the fuel pumps. It sounds like a bad TFI module to me. Once they get hot they stop working properly. The computer is signaled by the TFI module to engage the fuel pumps. If the TFI module stops responding the computer will think the spark plugs aren't firing and will kill the fuel pumps.

 

FORDFUELINJECTION.com shows how to pull them with the paperclip-
(I always thought that was cool)..
The computer runs its diagnostic once you turn the key:
The Fuel pumps are one of the first things it checks,- you should be able to hear them once the key is turned to on, or "run."
When pulling codes, its the first sound you hear. -it is on my '88 anyway-
-You probably allready know this by now from messin with it.
after the two minutes the truck fails- because the computer reached that point of testing the flow/pressure at the injectors- mabey the pressure regulator is failing?
-Dont keep disconnecting the Battery to re boot the computer to try and clear the problem. that only works after youve solved the problem.
And all that is doing is making the computer reboot and start another program of rituals, IF you do it enough it will eventually embed the problem into the system, and damage the computer thinking that the problem is supposed to be there-, making other components eventually fail, or burn out.
If you believe your fuel injection components are fine without problems, then focus on TFI module, the computer- If you got 22-25 years out of your trucks computer- you did well.

 

The computers don't just fail. They are sealed and in the cab. The only way they can fail is by water infiltration or a short in a sensor line that burns the embedded wiring on the board. Occasionally there is a power surge from a bad ground or bad alternator that will kill the ECU chip. Then the computer runs in limp mode. Like I said if the fuel pumps aren't running it's not likely to be the computer. They should run for 2 to 3 seconds when you first turn the key on. This is to prime the system and get pressure high enough to start the truck. If you don't hear them when you turn the key check the relays first.