power distribution box problem help! 94 sport

[ubernoob]

hello every one, got a strange problem with the under hood power distribution box and the little fuses/boxes that plug into it, the long standing problem is that every so often the truck a 94 explorer 6cyl 4.0 (im pretty sure) auto trans 2wd sport will die while driving or refuse to start,the solution has been to wiggle the fuses in the power distro box ,but naturally its gotten worse, one time i got some electronic parts cleaner and dielectric lube and clean it apply the lube and that lasted for several months, but of course the problem retutned, we bought a new power distro box from the junkyard, well i discovered that it was useless , they had cut all the wires rather than pull it with the connectors attached,
recently its gotten so bad were lucky if we can go around the block , i tried making the clips the fuses plug into tighter but that did not work i even plugged one in while i had all the connectors out of the box ,just one of them tho it would not even engage the fuel pump, thats what the main issue is the fuel pump is not getting power so it will just turn over and not start, i can post pics if that would help anybody concoct a solution, my theory is that perhaps because of the after market air breather thats on it pushing against the power distro box its warped the box and making it where they dont connect right any thoughts on a fix for this would be greatly appreciated, my wife starts school next week so a quick fix is needed

 

[Rick]

Have you tried swapping the fuel pump relay just to rule that out? It could be intermittently bad.

Where in AZ are you located? I'm in Wittmann.

 

[Anime]

The relays themselves do go bad, in particular those for the constantly-used fuel pump and PCM/ECM.

Match up the relay part numbers, and use some of the relays from the replacement box you got at the junkyard, and see if that makes a difference.

If not, there may be a larger issue, such as the fuel pump being worn out/going bad, which does happen, especially if it's the original one. Only fix for that is a new fuel pump.

 

[BKennedy]

Have you tried swapping the fuel pump relay just to rule that out? It could be intermittently bad.

Where in AZ are you located? I'm in Wittmann.

I'm with Rick on this. My Explorer was doing that and I replaced the fuel pump relay and it went away. I don't see how the panel could get warped inside the box enough to cause your problem. Try switching the fuel pump and APS relays. If it starts, and the ABS dash light comes on, then the relay is bad.

 

[ubernoob]

Have you tried swapping the fuel pump relay just to rule that out? It could be intermittently bad.

Where in AZ are you located? I'm in Wittmann.

yeah we bought 1 new relay and have tried swapping them around the problem does not change im in snowflake

The relays themselves do go bad, in particular those for the constantly-used fuel pump and PCM/ECM.

Match up the relay part numbers, and use some of the relays from the replacement box you got at the junkyard, and see if that makes a difference.

If not, there may be a larger issue, such as the fuel pump being worn out/going bad, which does happen, especially if it's the original one. Only fix for that is a new fuel pump.

when you wiggle the relay you can hear the fuel pump engage thats when you know it will fire up, but it usually dies in a minute or so but sometimes it will run and drive no problem, im not convinced that theres anything wrong with the pump just yet

 

[ubernoob]

I'm with Rick on this. My Explorer was doing that and I replaced the fuel pump relay and it went away. I don't see how the panel could get warped inside the box enough to cause your problem. Try switching the fuel pump and APS relays. If it starts, and the ABS dash light comes on, then the relay is bad.

the abs light and check oil light stay on constantly whether it runs or not, also the heater blows intermittently as well, there were no relays in the junkyard box

 

[Anime]

If if dies no matter what relay is used, then - assuming that it dies because of lack of fuel - I'd have to say it's the fuel pump itself, or the wiring from the pump to the battery/relay panel.

Perhaps there is a short in the wiring, and the actions you've performed thus far have worked because they also had the effect of moving the wiring around to prevent the short. There might also be some wires that have corroded internally or the wiring issue might actually be farther down towards the fuel tank/pump.

I'd say fuel pump though, if it dies then won't start, but will start again later on - that's a fuel pump that's worn out.

Either that or the PCM/ECM itself, the capacitors can leak on the circuit board and cause unsolvable electrical issues, since the leaks break the copper traces on the circuit board. I never had the vehicle suddenly die, but it does cause fuel pump/starting issues so it might just be a variation. Pull the PCM/ECM cover and look around the black cylinders for signs of leakage. Of course, it could be that the problem is both a bad PCM/ECM and a worn out fuel pump.

 

[BKennedy]

Did the power distribution box get wet internally somehow? I just don't understand how the entire box could be bad. I could see one or two terminals, but not the whole thing. If its the box, you might just be stuck with splicing all the wires into the new (used) box you got from the JY. Its really not that difficult and is easier than replacing the entire wiring harness for the vehicle.

 

[ubernoob]

im looking into getting some help with it, and the wife has started looking for a new vehicle this one was cut up by a teenager before she got it and has more problems than this one, im not very good with electrical but i can say that the problem really seems to be the relays not maintaining a steady connection because if i can get the relay to sit just right it will run fine for days ,its just getting it right,heat has never seemed to factor nor has any specific time frame like it does not quit when its run for 2 min it is very random how long it will go before it screws up again it can be anything from 10 seconds to a few months.

 

[yragsapo]

I have a '94 Sport 4WD. I was recently having a lot of problems with my blower motor relay burning out, when the weather got into the 90's. Went through 3 of them this summer. The last relay got so hot that it melted and slightly damaged the box. When I was talking to the mechanic, we discussed this and he said he could rig up a relay, outside of the distribution box, by disconnecting the wires from the box. I wonder if that might be a good solution for you, as well. Perhaps a relay, outside of the box, protected by shrink wrap or something like that, would be the best solution, given the problems you're having with the connection inside of the box.

 

[malohnes]

If its the box, you might just be stuck with splicing all the wires into the new (used) box you got from the JY. Its really not that difficult and is easier than replacing the entire wiring harness for the vehicle.

I agree!

[QUOTE="ubernoob, post: 3298512, member: 255601" im not very good with electrical but i can say that the problem really seems to be the relays not maintaining a steady connection because if i can get the relay to sit just right it will run fine for days ,its just getting it right,heat has never seemed to factor nor has any specific time frame like it does not quit when its run for 2 min it is very random how long it will go before it screws up again it can be anything from 10 seconds to a few months.[/QUOTE]

Then try to ascertain if there is a break in the power feeding them. If its a loose connector or plug that would explain it and ought be simple. If its corrosion or an actual break in the wires, then BKennedy is right on.

 

[jiffydarren]

I'm having this same problem, but not that severe. I'm planning on hitting the pick and pull on Wednesday. Mine has a fuel pump new within the past few years... when I try to start her up and she don't go I leave the key on and fiddle with the relay till the fuel pump kicks on then she's good. Let me know how this goes.