Vehicle stop running and wont start

[n4baf]

I have a 1993 Ford Explorer XLT; while driving yesterday afternoon the vehicle stopped running while I was on the highway. The radio and everything else seem to work fine. The vehicle will turn over without any problems, but want start. I was told that the ignition coil might be faulty. We checked the spark plugs for spark and didn't get any. I have the Haynes repair book and tested the coil. The ohm readings are slighly higher than the specs when testing the secondary coil resistance. The book isn't clear. It says connect an ohmmeter between the secondary termainals. The resistance should be as listed in the specifications. Then it says If continuity doesn't exist replace the coils. I have resistance between the coils, but i don't have continuity. I also noticed that I don't hear the fuel pump engage with I turn the start switch to on. This always happened for about 3 secounds when I turn the key. Does this sound like a faulty ignition coil?

Brian

 

[budwich]

nope... sounds like a faulty fuel pump relay.

My guess on the resistance / continuity... is they mean if you have an "open" (ie. no continuity), then replace the coil. If you have "resistance" then you have some continuity but depending on high or low the resistance, the coil may still be a problem.... OK? But I would check the fuel pump relay... lots of posts on all kinds of Ex's with this problem some time during their life span.

 

[n4baf]

I checked all the relays in the distribution box for continuity with and without jumper wire and they all clicked and had good continuity.

 

[marragtop]

Check and makes sure that the inertia switch hasn't tripped, and that the wire on the bottom of it is on tight. Your next option would be the fuel pump itself which is a pita to replace. That's the very last thing I'd do. You can get a fuel pump relay for about $5. I'd consider replacing that before pulling the tank.

 

[n4baf]

Inertia switch

I checked and the inertia switch did not trip, and the wire is tight. I did notice that I'm only getting about 1.4 volts on both terminals going into the inertia switch. What could be causing this?

 

[budwich]

you only did "one check" by checking for continuity.... you need to check to see if the relay actually pulls up when it supposed to. If "battery" doesn't get THRU IT, then it's a relay problem. If battery does get TO IT, then its a problem elsewhere.... ie. controls to the relay.

 

[n4baf]

i checked for continuity; also i connected relay to positive and negitive with fused jumper wire to battery terminal and got the click; after the click i tested the other end normally closed for continuity. It all checked out. On the distribution box where the fuel pump relay sits one terminal has 12v and when i turn the starter to on i don't get 12 volts from the any of the remaining inputs.

 

[DeRocha]

I checked and the inertia switch did not trip, and the wire is tight. I did notice that I'm only getting about 1.4 volts on both terminals going into the inertia switch. What could be causing this?

This is correct...

When you turn the key to run the fuel pump electrical circuit will send 12v to the fuel pump to pressurize the fuel lines in preparation for the start cycle. This circuit will continue to read 12v as long a the engine is rotating (RPMs>0); otherwise the circuit will kill power to the fuel pump after a second or two. As such it may be hard to "catch" this 12v reading (with a digital meter) because it happens too quick.

So retest by hooking up your meter to the inertia switch and then turn the key to catch the quick 12v reading... If you get 12v then your fuel pump is most likely dead... You can put a fuel pressure gauge on the shrader valve (on the fuel rail) and test for adequate pressure (30lbs+). Check out the info in the maint link in my sig for info on replaceing the fuel pump...

 

[n4baf]

Thanks all for your comments. It turned out to be a blown EEC Fuse. My brother came over and checked each fuse for continuity. I only looked at each fuse without pulling them out, and my main concern was checking each relay and fuel pump fuse. The EEC fuse was blown so I replaced it and my explorer started right up. What might cause this fuse to blow? Again thanks all for your comments.

 

[n4baf]

Still need help

The problem I posted in September stopped and I don't know what was blowing the EEC Fuse. I have been driving everyday and yesterday while deliving mail. Dead! My explorers engine shutoff and it want start. It keeps blowing the EEC fuse. I have no clue where to start. Should I have it towed to Ford Dealer?

 

[Turdle]

Try A new fuel pump relay, or switch it with another. It could have a shorted coil.

 

[n4baf]

Ford Code Reader CM 543 "Fuel pump secondary fault"

Thanks all for your response.. I replaced the circuit breaker and after about 8 fuses. I got it running again for about five miles. I replaced more fuses and was able to make it home. I purchased a Ford Code Reader and got a CM code 543 which means Fuel pump secondary circuit fault. Any help on what can be causing this to blow my EEC Fuse.

 

[savagefan]

You have a short circuit to repair or your fuel pump is about ready to quit and is drawing big amps. Time to break out the ohmmeter and do some sleuthing.

 

[Papa]

Many years ago I found that a home made test light constructed a twelve volt light bulb with some wire soldered to it and a couple of alligator clips can be an invaluable troubleshooting tool. I know it is not elegant and even though I own a couple of very nice DVM’s and a few analog meters as well the test light can work magic and it only takes one person for many of the tests because the light will glow bright enough most of the time too be seen from the other end of the Explorer. With just a little patience you can follow many electrical circuits to great lengths, sleuthing if you will.

 

[Hihelix]

Just curious if you ever figured out what was blowing your EEC fuse? I am having the exact same problem on my 92.