Help! won't start

[JTHale13]

I've done several searches and haven't found the answer I'm looking for yet. I have a 93 explorer xl and it won't start. It'll start for a couple seconds off of starting fluid. I've grounded the fuel pump test lead with a gauge hooked up and I get around 35 psi. When I turn the key to the run position without the test lead hooked up the pump doesn't turn on and I get no pressure at the fuel rail. Please help me get this thing running before it gets too cold outside because I don't have a garage. Thanks so much for this site.

 

[ragajungle]

More details please...

Where are you hooking up the test lead? Under which circumstances do you get pressure? Key on Run?

Some possible areas...

>Check the starter solenoid/relay on the passenger inner fender wall - the EFI gets its juice from it - damaged wires caused me issues on 94 ex..
>Check fuel relays in power distribution box
>You may have a corroded ground wire to the harness connector that plugs into the sender (above tank) had that on my bronco II.

 

[JTHale13]

I hooked the test lead to the fuel pump wire on the dig plug and the other end went to ground just as my chiltons manual stated.

 

[MrShorty]

I've done several searches and haven't found the answer I'm looking for yet. I have a 93 explorer xl and it won't start. It'll start for a couple seconds off of starting fluid. I've grounded the fuel pump test lead with a gauge hooked up and I get around 35 psi. When I turn the key to the run position without the test lead hooked up the pump doesn't turn on and I get no pressure at the fuel rail. Please help me get this thing running before it gets too cold outside because I don't have a garage. Thanks so much for this site.

Have you looked at the wiring diagram in your Chilton's manual? First thing I'd have you do is study that so you can see how the fuel pump circuit works. Since the pump runs when you ground the relay, the pump itself is likely good. You need to look at why the PCM isn't telling the relay to close. 1st thing I'd probably look at is if the PCM is getting power.

 

[JTHale13]

Okay I looked at the wireing diagram but I'm not experienced with reading them so I'm not sure what it tells me but I checked the crash switch and its working properly but I checked the voltage at that switch and with the key on I only get 5.6 volts but if I ground the fuel pump test lead I get 12 volts.

 

[MrShorty]

Okay I looked at the wireing diagram but I'm not experienced with reading them so I'm not sure what it tells me but I checked the crash switch and its working properly but I checked the voltage at that switch and with the key on I only get 5.6 volts but if I ground the fuel pump test lead I get 12 volts.

Sounds normal.

As much electronics as are in modern cars, the skill of reading a wiring diagram is, IMO, an important skill to pick up. What I wanted you to see is what is responsible for closing the fuel pump relay. You should see a power wire coming from the EEC relay to the coil side of the fuel pump relay which then goes to the PCM (which applies ground to this circuit to close the fuel pump relay). Your problem seems to be somewhere in this circuit -- specifically, why isn't the computer applying ground to the fuel pump relay to close the relay?

 

[JTHale13]

Thought I'd update everyone on what I found. The engine computer that is behind the passanger side kick panel had gone bad. I was able to get a new one for $109 at the local autozone and I had to give them my old one but the explorer is up and running. I bought the explorer for five hundred bucks not running so after a battery for a 100 and and a computer for 109 I've got a great running explorer for just over seven hundred bucks. I'm doing my part to recycle.

 

[MrShorty]

Well done. Because diagnosis is most of the battle, would you care to describe how you traced the problem to the PCM?