Lifting Fuse Relay Box? - 1996 Explorer 4x4

[MotoDog]

I have the dreaded Fuel Pump Intermittent problem. You DON'T hear the fuel pump pre-charge sometimes.
I replaced the fuel pump a year ago. Still, once in a while the Explorer won't start. I have tested all the relays
and diodes with 12V and a 1 amp load. They all seem fine.

I have jumped from the battery to the Inertia Fuel Shut Off, and it starts fine.
By the way, the fuel switch above passengers feet, is a great way to get a direct connection
to the fuel pump for testing!

Last time I thought I had it fixed I cleaned the relay terminals AND the 2 Diodes.
When I inserted the diode that feeds the PCM relay, the Fuel Pump started right up.
Now I have put the inertia switch back in (after putting a shorting wire across it).
Thinking it was OK.
Months later, not working again. Thinking a bad connection to the bottom of the Relays?


Now I spent an hour TRYING to push the right plastic tabs to pull the Fuse Relay Box up to check the wires
coming in from the bottom. I gave up. The only way would to break everything and then you would know the Magic to lift up the fuse box. 2 or 4 Screws could have done fine, buy no, the Ford geniuses had to have multiple plastic latches and a couple levels to ponder. Why do I have to break everything to figure out how it works.
So How and Where do I push to UN-Latch the Fuse Box for my next set of tests.?
I guess I could break everything and then glue it back. What a crappy design.

Anyone know the magic or is there a picture out there?

Thanks
Mike

 

[koda2000]

Strange issue. What brand of fuel pump did you install? I haven't figured out the fuse box either, but if the relay contacts are brass you might be able to clean them with lemon juice and some Q-tips.

 

[MotoDog]

I replaced the fuel pump with a kit from Car Quest. About 2 years ago. You change just the pump, using the old bracket.
I soldered all the wires and shrink sleeved them. This was a big effort, the car was outside in the snow.


Well It is hot already this morning. I have been working out in the sun for an hour.

I know the wiring well, after a year of this . With the Hains manual I have drawn a diagrams of everything.

You can't fix the problem until it happens again, intermittently .

I tested the PCM and Fuel Pump Relays in the shop with a Power Supply and 1 amp load resistor.

One Diode is critical too, it feeds power to the PCM Relay Coil. It drops about 0.7 volts in forward direction.
Does not conduct in reverse direction.

I checked the fuel shut off switch. It is fine. This is a good place to test the Fuel Pump.
Anyone having questions about Pump Working, should go right the the Fuel Shut off switch.
From there a wire goes directly to the back, through a connector to the pump.

Clip on the Green and Yellow wire and it out the door to the Bat Plus and you can hear the Pump run.

So, It is the wire (or connection ) from the Fuel Pump relay to the Inertia Fuel Shut Off Switch above the
passenger's Feet.

Since I can not figure out how to separate the Fuse Relay box, with all its plastic tabs, I will probably have to remote the relay or put a wire on it, and run a separate wire to the Shut Off Switch.

I am looking for a place to go thru the firewall with a wire next?"

Mike, in Hot as Hell Yucaipa, Ca.

 

[Turdle]

I've had an issue with bad connections in the relay box myself. I , (ahem, cough) , um, fixed it by just giving the tabs on the relays a slight "twist" with needle nose pliers,to make them bite into the socket lugs a bit better. Just a slight twist, barely noticable should do it. too far and they won't go back in.