My 96 Explorer 4.0L won't start at all today. The battery has plenty of juice and the starter cranks the engine well but there is just no fire. I even scanned for codes and none came up.

My guess is that it might be the electronic coil pack not sending any spark to the plugs. I'm only guessing now because of an episode that happened 4 days ago.

On Sat., my wife went to start the engine and it shut down after a second or two. This happened a total of 3 or 4 times in a row. When it did stay running it ran like total crap. I told my wife to rev the engine a few times and that seemed to clear it up. It happened again to me later that day. It seemed like it was flooded when it ran like crap.

I don't know if the story above has anything to do with it not running now. If anyone has an idea of what might be wrong and how to check it, please let me know. I'm lost.

 

You need to determine if the problem is fuel or spark related. When you turn the key to the ON position, do you hear the fuel pump prime for a second or 2? If not, then you have a fuel delivery problem(fuel pump, FP relay, inertia switch), . If you do hear it, then check for spark at the plugs.

 

I'm having a similar problem with my '97 (4.0 OHV). It seemed like the longer it sat the longer it was taking to start when cranking the engine. I thought it was a fuel problem but a few days ago it wouldn't start at all. I checked for spark with a timing light and NO SPARK. I can hear the fuel pump pressuring up when I turn on the key. Here's what I checked so far:

Black wire going to some unknown small black device bolted onto the coil pack was partially eaten through by mice. Checked for continuity and it checked OK. Cut out the bad part and soldered it anyway. No start.

Battery: all cells test very good with a hydrometer and it charges back up (after trying to start the engine) quickly with a battery charger.

Pulled the fuses for the ignition and put them back: all OK. No start.

Tried to start with fully charged battery and charger connected: no start.

Voltage to coil with switch on: OK

No start.

Coil resistance: OK

No start.

Checked voltage to crankcase position sensor with switch on: OK. The funny thing is when I reconnected the CPS I could hear the fuel pump pressuring up.

Started right up!!!

Is it possible that a bad ignition switch could allow it to crank but not start? Or what about an alarm system? There was one on this Explorer that I had removed when I bought it used from a dealer. There is still a red LED installed in the dash. Are there alarm systems that will allow it to crank but not start? The ignition key does not have any microchips in it (from what I was told by the Ford dealer) and hardware store duplicate keys were working fine. The original key has the same problem.

I intend to check the fuel pressure if I can ever find a local auto parts store that has the correct gauge. I also plan to get an inline spark tester if I can find one locally. I really don't want to pay $6 shipping for a $4 spark tester

So far the only indication I have found is a possible dirty connection on the crankcase position sensor but this is hardly conclusive. But I guess it wouldn't hurt to just remove the connector, put it back, and try starting your Exploder.

 

if your keys are not pats keys, here is whats wrong. To put alarms or remote start on this vehicle, you have to take the computer pill out of one of your keys and glue or silicone it to the side of the switch. at times, the pcm will receive an incorrect signal from what it thinks is the key--no start. look for this "pill" and remove it. then you will have to reprogram your keys.

 

Following what marragtop has said you look for spark and fuel:

1. pull a plug (what does it look like) - turn over the motor with a plug grounded (spark?) - check more than one as the coil is paired

2. did you hear the "whir" of the fuel pump in the gas tank when you turned on the key (not starting the truck)? Have someone close to the tank listening to be sure but usually you can hear it if the window/door is open.

3. for $25.00 you can buy a fuel pressure guage to hook up to the fuel rail it should be near to 40psi without the truck running

If it's fuel related it could be as simple as a fuel relay in the PDB but it could be fuel pump or even fuel pressure regulator. Spark is easy to diagnose too but let's narrow it down a little.

Keep us posted.

 

Thanks to all for your replies. A friend helped me diagnose the problem. Turns out it's the fuel pump. The vehicle was in too noisy of a place to hear if the pump was pressurizing or not. My friend went with me to check it out since we needed one head underneath to listen. No pump noise was heard. We took a mallet and banged on the tank while the other cranked the engine and she fired right up and we finally got her home. I just got a new pump and filter about an hour ago and plan to put them in tomorrow morning.

Once again, thanks for the replies.

 

I'm not sure about the GenII Explorers but the GenI fuel pumps are in the gas tank (I'm sure they are the same). That's a pretty big job. If everything comes apart easy it's still a tough job. If there are stuck and rusted fasteners... yuck. Not particularly complicated just difficult working with the bulk and weight of the tank. Two men is best. Hopefully the tank is near empty when you start. Try to get as much fuel out as possible before starting if you can. Haynes has a decent explanation of changing over the fuel pump.

Good luck!

P.S. please be safe when working down there

 

Thanx! I got the Haynes ready to go and I'll be heading to my buddy's garage in about an hour from now to get it done with his help.

 

Make sure you have a Ford fuel line disconnect tool. You will need that to get the lines off the pump fittings. There are many horror stories about people trying to disconnect the lines without the tool.