Fuel pump won't turn on...

Ok. Smashed open the piggy bank and gave the battery a good charge and jumped out the terminal on the EEC test port and the car started right back up again! Pump came on when i turned the key on. The new EEC is also in place now. The new and original EEC seem to be operating the same, so either I was unlucky enough to get a tested, refurbished EEC with the exact same problem as my current one, or my problem wasn't the EEC. I'm pretty sure I'm going to keep the refurb given that my original is now 20 yrs old and probably only a matter of time bf something happens.

Raining here today, so tomorrow I will start working off the previous thread and begin to figure this out.

Thx for keeping me in the game. I really want to be able to fix this myself.
 
Problem solved. Thank you so much for all those who took some time to share some of their expertise with me. Can't convey enough my thanks.

Seems that there are a million threads out there discussing this issue, so just let me close by saying...

Looking back into this thread, my problem was solved very early on, when the EEC was pinpointed after jumping out the EEC test terminal. For what it's worth, I was able to buy a refurbished EEC that was tested with a warranty for a very reasonable price at a national chain store.

Every single thing after that thread was brought about by trying to work through this with less than optimal voltage in my battery. This is a completely stock 92 lx 5.0, that remains garaged and rarely gets driven in the NY winter. My idea of battery maintenance was running the car for about 30 minutes every Sunday during the winter. Obviously, this isn't good enough, even although it's a 1 year old Motorcraft battery. As soon as it was suggested to charge the battery, my problem began to resolve itself. I purchased a maintainer to keep my battery in better shape from now on.

I also began to get frustrated when my problem wasn't immediately resolved when I swapped out the EEC a few days ago. As a result, I kept going back and forth switching out the new and old EECs. This also prolonged my problem. My fate improved when I made a decision to stick with the new one (some of the reason for me switching was that I needed to return the new one within 30 days if it wasn't the cause of my issue). When you remove the harness, it isn't exactly plug and play, and the EEC needs a few minutes to get it's crap together. This is something I should have probably known, but it took me a bit. For example, once everything was corrected, I needed to unplug the harness from the EEC in order to shove the EEC back up into the kick panel. Once I did that and reconnected the harness, the fuel pump would prime again. After shouting obscenities like the father from A Christmas Story, all of a sudden the pump primed and I never looked back. Its almost as if it took a minute or so with the key in run for the EEC to calibrate.

Careful with the EEC test harness, and make sure you get a good connection for your jumper. As with all our plastic parts under the hood of our stangs, years of heat and cold have made them brittle. Be careful when you handle them. Also, as previously suggested, make sure you get a good ground for that jumper. I wound up actually making one with two spade bits (much like on the diagnostic reader) that slid right in to the test port, and stayed put. A crappy jumper probably also cause me issues.

Happy New Year to everyone!
 
Not sure if anyone is still following this, but I am working on my mustang and have followed this diagnostic and get thru the power path...fuel pump runs when the test is ground,

Control path:
Relay: The red wire for the fuel pump relay coil gets its power feed from the ECC relay.
No 12 volts here, and the ECC relay has failed or there is bad wiring or bad connections
coming from it. The ECC relay is located on top of the computer, which is under the passenger’s
side kick panel. It is not easy to get to, you must have small hands or pull the passenger side
dash speaker out to access it.

There are not 12 volts at the fuel pump relay red wire...so now what? have a spare computer and ECC Relay and Fuel Pump relay, and still have the issue. So that leaves me to wiring...not sure how the wiring went bad sitting in a garage for 13 years, but obviously it has.

I am not following exactly where the failure could be...
 
Not sure if anyone is still following this, but I am working on my mustang and have followed this diagnostic and get thru the power path...fuel pump runs when the test is ground,

Control path:
Relay: The red wire for the fuel pump relay coil gets its power feed from the ECC relay.
No 12 volts here, and the ECC relay has failed or there is bad wiring or bad connections
coming from it. The ECC relay is located on top of the computer, which is under the passenger’s
side kick panel. It is not easy to get to, you must have small hands or pull the passenger side
dash speaker out to access it.

There are not 12 volts at the fuel pump relay red wire...so now what? have a spare computer and ECC Relay and Fuel Pump relay, and still have the issue. So that leaves me to wiring...not sure how the wiring went bad sitting in a garage for 13 years, but obviously it has.

I am not following exactly where the failure could be...
I doubt anybody is paying attention after 5 years, get on the 5.0 tech threads and post your problem and get some advice thats a little more advanced.
And welcome to stangnet
 
  • Like
Reactions: BlackCrow