i have a 94 f150 and i don't know how to locate the ecm. if someone could let me know that would be awesome. i am not getting fuel and i have tested the fuel pump, replaced the pump relay, checked fuses, inertia switch, and wire continuity. All that is left is the ecm, ecm relay, and.... please help!

 

follow you harness to the drvr side firewall. The huge connector closest to the fender is the ecm pigtail. loosen the bolt, remove the plug. Two bolts hold the cover, remove that and the ecm will slide out. You may have to wiggle it a bit to help it out. G/L.

 

thanks counterman. Tomorrow's the day and i got a funny feeling i"ll be replacing it.

 

Could be a fuel relay or ECM relay. Both should be by the airbox on the drivers side fender.

 

You will also have to take the front left tire off and the screws out of the inter fender and take it out between the fender and the inter fender.
Make sure you use jack stands while working there with the tire off.

But make sure you have power to the PCM Computer and it has a good ground before you remove it and say it is bad.
About 35% of the time you will buy a bad Computer as they did not fix what was wrong with it when they got it. So do not swap your good computer for a bad one. Most that are sent in for repair they do not find anything wrong with them.

The computer is located in the drivers kick panel and removed from under the hood through the fender and inter fender.



/

 

Thanks for the help i have located and tested the pcm and i think it's bad. I want to do a couple more things to make sure. i want to do the coded self test and the eec module elects check but i am not 100% on where the fuel pump relay power distribution box connection point 50. anybody explain or give another test idea?where do i get a cheap pcm?

 

Not sure what you are asking.
"power distribution box connection point 50"????

Do you hear the fuel pumps come on for one second when you turn on the key?
If not ground pin #6 of the EEC self-test connector with the key on to see if the pumps will run?

 

i have not been able to get the fuel pump to start with the key or jumping with the dlc. the fuel pump is good however because i replaced it thinking it was the problem. the truck still won't start but the old fuel pump doesn't work when connected to battery so i think i had 2 problems if you can believe that. i have done every test on the eec power and ground checks and had one bad test. the eec module sig rtn grd and according to the haynes manual its a bad eec. i just want to make sure before i spend a couple hundred bucks.

 

If the pump will not run with the DLC pin #6 grounded and the key on it is NOT the eec computer.
Sounds like the Fuel Pump fuse is bad.




/

 

Thanks for the input subford. You have been a lot of help so far and the pics rock. I will poke around in there a little more. how would i check the power diode?

 

If the EEC Power Relay clicks when the key is turned on then the power diode is OK.

Normally you check the power diode with an ohm meter. A power diode is like a one-way check valve, it lets power go one-way but not the other. So you should have an ohm reading one way the way the leads are connected but no reading the other way on the ohm meter.




/

 

well, I think i am even more confused than ever. After reading the previous post, i went to the truck and tried jumping it with the dlc and it worked, although i used the gray one to the side i believe it is the sti. i wiggled the power diode and relay and turned the key and the truck started. needless to say i was pumped. i went back the next day, reconnected the battery and turned the key, nothing. now i can't get the fuel pump to come on or anything. it's like something out of a bad dream. i did the self test in the haynes manual and it says fuel pump secondary circuit failure pcm to ground. i have checked the obvious even some of the less obvious. what am i missing????

 

If you grounded pin #6 of the DLC to ground and turned on the key to run the pumps then the error code is normal and OK, just clear it. You clear codes by grounding the STI wire and when the MIL lamp starts to flash you remove the ground from the STI wire.
You only use the STI wire to ground to run the Self-Test and not to run the fuel pump(s).

I have no idea what the tests are in the haynes manual as I do not own one but I hear they are good for starting fires if you go camping.

 

i know what you mean

 

Well everybody, thanks for the help so far, but the truck still isn't running. I located and removed the computer and found corrossion. i cleaned it, put it back, and it worked truck ran for about 36 hours. I have replaced the fuel pump, fuse, relay, and the computer and it still isn't working. I recently got wind that my after market alarm could be affecting my fuel pump (electrically) and now i would like to remove my alarm all together. this problem is making me want to kill my truck so if you have any last words that might save it's life, we would both appreciate it!