Hello all, I have a 1993 F-250 extended cab 4 x 4 with a 460.

I had problems with shifting, and after replacing the instrument panel it worked fine again. A week later it would crank but not start. I pulled the ECM and it has bad caps in it, so I replaced it with a rebuilt one.....now....I have no power at all to the cab, ignition switch, headlights and the ignition does nothing.

I have checked every fuse and circuit breaker in the truck and they are all good. I have power to the fuse block on the driver's side under the hood. It appears I have no power to inside fuse block. Every schematic I have found in books and on line doesn't show how battery power gets to the cab. I am guessing there is a fusible link somewhere....?

Has anybody else had this problem? Perhaps there is something by the ECM that gets knocked loose when changing it? Anybody know if there is a fusible link, and where is it at?!?!?!

can't work on anymore today since the rains rolled in....so any direction is appreciated.

 

You might check the fusible links that are located at the starter relay.
It is very unusual for an ECM replace to wipe out a fusible link, but strange things happen every day.
A link should provide power to the ign sw.
Also there should be a fuse in the power dist panel that supplies power to interior fuse panel.
If there was no other possible reason for the power problem except changing the ECM, I would unplug it and recheck plugs and connections.

 

Got a break in the rain. Unplugged and plugged in ECM, no difference at all. Checked power at inside fuse panel, have only .3 volts on a few. Checked voltage on fuses in power distribution center under hood and all except one had full 14 volts. The one fuse at the top in center (20 amp) read at -.6 volts. Negative....huh? Can't find a decent diagram on line to confirm, but some show that as a fuse for the ignition switch....

Ran out of daylight, so will have to check point to point from solenoid/ relay by battery back to fuse panel and hopefully find something between those two points. The negative reading has me scratching my head.

 

Now- Still no power to lights, dash, ignition, etc.

Fusible links coming from relay to Alternator test good. Found misplaced engine ground and moved it to a better area for contact, and confirm continuity. (Truck had an amazing amount of very badly done wiring for accessories when I bought it. I have step by step taken off all the useless gadgets and put wiring back to stock.)Cleaned as many grounds as I could find under hood.Replaced negative battery terminal, positive has three wires so I cleaned it . Still nothing at distribution panel on only one 20 amp fuse. All other slots have full voltage. There is a pair of wires that comes off of relay by battery and goes forward into the harness there. Tracing them will be difficult, but next in line.

1. The problem seems to lay between the battery/ relay and the distribution panel. Anybody have schematics connecting the two, or photos of the harness or bottom of power distribution block?

2. Could it be battery cables? Negitive disappears into a glob or grease and dirt at chassis end. Anyone got a picture or drawing or where it may actually attach?

3. Problem happened after I replaced ECM, are there known wires that get disconnected or disturbed when doing this change? My guess is it has to be something in that area that I can't easily see. (I did learn what a "Spout Connector" was today by searching the ford part number....).

Hello....anyone?

 

You could try to go on the expedition forum and get a hold of (1995 moose). He really knows a lot and can give you step by step instructions. Just remind them on the site you know it is for expeditions but fords are basically all the same

 

I sent some Power Distribution schematics to your email..

 

.....and....progress. My hunch was right, but not for the reason I thought. The wiring harness plug for the interior of the cab was unbolted at the firewall and not making contact. I've had the truck over 10 years and never touched that plug. The dirt of the plug looks like it was this way a very long time, and I must have bumped it the last little bit. Plugged in and tightened down and the dash has power and the engine cranks...


BUT....still no start. Replaced coil (terminal was broken off), PCM (three bad capacitors), cap and rotor (just because). Drained fuel in one tank and put 5 gallons fresh in it to get the truck running. It seems like to wants to fire but just won't. Cranks, jumps like it's starting and then back to cranking......are there sensors or other bits I should be checking next?

 

Something you might consider,

If you remove one of the spark plugs, see if it is dry or wet with what could be fuel with too much water in it.
If it is wet try to lite it with a match, if it lites up and burns easily fuel should ignite in the cyl. If not, you might have fuel with too much moisture in it.
Let us know how you make out with this, thanks.

 

Update: Took the ignition control module out and it tested good at the parts dealer. Put it back in, and tonight I have a second set of hands- so was able to check spark....it is outstandingly good. (YES!)

I had actually drained a tank to try and be clear of water...even ran what I took out through a water removing funnel and got nothing. I tried both front and back tanks while cranking to no change, so I suspect maybe the fuel pressure regulator? I don't smell gas at all after cranking, and the air filter assembly is off. Plug looked dry also.

Anybody know what fuel pressure I should have at the injector rails up top?

I will update and complete the thread as I move along, you never know when somebody else runs into the same thing later....it's so frustrating to find a thread somewhere, follow it...and never see the answer!

Thanks for the help so far.

 

Did you ever remove one of the plugs to see if you are getting any fuel to the cyls?