94 explorer wont start

[ecreek]

i bot this 94, v6, 4dr that wouldnt start. the owner said the fuel pump was out. i could use a wiring diagram or some assistance in getting to the root of the problem. i dont want to change the fp without verifying it's dead. any help would be much appreciated. thanx

 

[Iron Weasel]

 

[Roadrunner777]

When you turn the key you should hear a hum or a buzz for maybe a second. If so, then the pump motor is at least running. If not, then... I do easy things first. First would be to get into the power distribution box under the hood and locate the fuel pump relay. Swap it with any other relay in the box, like the blower relay (the relays are all the same spec). While you are there, look at fuse #16 and make sure it is ok.

If it still doesn't work, then check the inertia crash switch, under dashboard, passenger side towards the trans hump. Look for a box with a grey connector and reset switch.

If it is running, then you should do a fuel pressure test.

 

[mr cribb]

I'd check for fuel getting to the motor. Then get a fuel pressure gauge to test the fuel pressure at the regulator. If your getting good pressure, and fuel to engine then obviously it's not the pump.

It could be spark related unless you've already checked that. Trouble shoot all areas before you go and throw parts at it.

 

[ecreek]

cant hear a hum with ignition switch turned on. i'll ck the fuse and inertia sw & let u know what comes up. the front wheels look knockkneed so maybe they baja'ed the sw into tripping.

 

[ecreek]

my thanks to Iron Weasel for the wiring diagram.

 

[Iron Weasel]

An easy way to check the pump itself is to use the fuel pump diagnostic lead.



If the pump runs, then the pump itself is OK. If it doesn't run, it's dead.

By the way, that's a diagram of the DLC (Data Link Connector). It's located on the passenger side near the firewall right behind (when looking towards the vehicle) the power distribution center (where all the fuses are).

 

[ecreek]

what do i short the pin to? ground? or another pin on the connector?

 

[Iron Weasel]

Yeah......jump that lead to ground.
Get a length of wire and run it from that lead to the negative terminal on the battery or another suitable ground point.

Might help if I actually told you what to do with it.
Derp on my part.

 

[Roadrunner777]

If memory servers, doing this commands the EEC to turn on the fuel pump. Just to be complete, if this does not work, it could be the fuse, relay, initial switch, wiring, or the pump.

The best possible test for the pump is obviously a bench test, which is a PITA. The next best would be to hot-wire the pink/black wire on the initia switch. This is a straight-line to the pump.

Maybe it was just the relay. I hope the OP comes back with results.

 

[rustbucketMI]

If you have a spare 12V battery you could crawl underneath the car, ground the negative termal to the chassis, and quickly tough a wire connected to the positive termal of the battery to the positive lead on the fuel pump. I would suggest putting in a momentary switch inline with the positive wire. If the pump make a noise it probably works, if not then it's probably dead

 

[ecreek]

its the pump

checked fuse 16...ok checked relay & inertia sw....ok ok...checked voltage at fp connector.. 12 v... slaved in 12v to fp connector....current flowed, no fp noise.

 

[Roadrunner777]

I guess you know what's next, if you apply voltage to the pump and it doesn't pump, it's probably a bad pump. The original owner said the pump was bad, I think you have confirmed it.

 

[ecreek]

half full gas tank

b4 i drop the tank to chg fp, how would i get all that gas out of the tank?

 

[Roadrunner777]

Look for threads about changing the fuel pump. There are 2 methods, one is to cut an access panel in the floor pan, the other is to drop the tank. If you are going to drop the tank, you will need to pump or siphon as much as possible. People describe this tank as hard to handle and 2 person job with as little as a quarter of a tank.

On this, I highly recommend you read other threads and understand what you are going to be doing. An hour of reading could save you a day of labor.

 

[bjvincmrs]

We recently had to replace the fp on our 94. Well, had a garage do it. They charged about $600! The old one was still running, the mount broke and it fell into the tank! They said that was the first time they saw that.
Good Luck

 

[MrQ]

Be very careful with an almost empty tank. If you decide to drop it make sure to take adequate safety precautions. Remember its not the fuel that's as flammable as the fumes, which an empty tank will have in abundance. Just a heads up.

 

[mr cribb]

I only have some experience on changing a fuel pump. One was on my old 97 chevy truck. it was a sideways mounted 25 gal tank. It had a 1/4 tank of gas in it, still took me and my buddy, and a hydraulic jack to lower the big *******.

The 2nd one was on my 94 Bronco. That was a ROYAL PITA!!! The truck was from Ohio so 14yrs of salt (owned in 2008) and rusted bolts, tank straps the whole shebang.

Hopefully you don't have to deal with the northern road salt issue, or a truck that came from there. If ya do PB Blaster is your best friend.

And just as a precautionary advisory..... please don't use a torch to cut off any rusted bolts near the gas tank. I know this should be OBVIOUS but there are some interesting individuals out there. I would also probably stay away from a cut off wheel/ dremel tool to avoid sparks.

 

[ecreek]

changed fp

dropped the tank and changed the pump. got the gas out by pulling fill hose off and siphoning. left fuel lines on pump assembly and removed motor, replaced and put every thing back together. had a helper. even then it was a chore. thanks all for advice and diagram.

 

[69Explorer69]

dropped the tank and changed the pump. got the gas out by pulling fill hose off and siphoning. left fuel lines on pump assembly and removed motor, replaced and put every thing back together. had a helper. even then it was a chore. thanks all for advice and diagram.

Well did it start?How does it run!!