I have a 97 Explorer Sport with the 4.0 liter (No OHC). Was running fine until a week ago. Left the house, got about a mile away and noticed it was running rough, so I turned around and went home. The next day I went out to check the codes. Got a P0300 (misfire) on the scanner, but also noticed white smoke and gas dripping from exhaust pipe. Checked a couple plugs, noticed a heavy gas odor on the threads. Assumed I was having a problem with the ignition coil, so tohight I replaced the coil, plugs and wires. Now it will not start at all. It will crank and begin to start but then back to cranking.

Anybody have any ideas on where to go now???

I had an appointment to have it inspected tommorrow. Oh well, I'll have to postpone that one.

 

300 is a multiple misfire code. It doesn't mean the coil is bad. It means the PCM detected a few inconsistent feedbacks and assumed a cylinder or more isn't firing correctly. Now you have to find out why - might be a coil, but apparently it wasn't.

Certainly gas fouled plugs can cause a misfire. What are the conditions of the new plugs? Is there a consistency like all right good and all left gas fouled? Or maybe lean and dry? We might be looking at a fuel delivery issue. A bad pressure regulator could be flooding the motor. Try to put your accelerator foot on the floor and leave it there - now try to start it. If it goes, it was probably flooded. This technique shuts the injectors off. It's programmed that way to clear a flooded engine.

Do a little more probing on the basic air/fuel/spark requirements. I'm confused as to the original white smoke - this usually means a coolant leak into the cylinders. What's your water level look like?

 

OK, I was able to get it running again by depressing the gas pedal all the way to the floor. Now I am back to rough idle (multiple misfires). I looked at the old plugs, and there is no left side right side difference. it seems to be consistent with all the plugs. I did notice that even with the short time I did run the engine again, I was getting gasoline dripping from the tail pipe.

What should be the next step? Clean the MAF sensor? How would I test the fuel pressure regulator?

 

Looks like that was an xlnt suggestion from jharger about holding the throttle down.

Does your 97 still use a vacuum controlled fuel pressure regulator? If it does, try running it for a few seconds and pull the vacuum hose off of the FPR, it should be dry.

If it is, i'd still screw on a fuel pressure gauge & make sure pressure isnt too high & that it will hold pressure.

Fuel pressure specs will be in your Haynes/Chiltons

 

I have not had a chance to check the FPR vacuum line, but some additional info that I forgot to post earlier - when I started that engine I ran it at ~2000 rpm and the scanner picked up a P0340 DTC? I', still getting gasoline dripping from tailpipe.

 

So the CMP/cam sensor circuit is open. It times when the injectors fire & is located at the top rear of the engine where the distributor used to be.

The CMP grounds to the drivers side of the radiator at the top. Black wire/white stripe. Check to make sure that ground screw is clean & tight. And check the wiring at the sensor for any breaks.

 

Looks like Ford changed some stuff here from EEC-IV like mine to EEC-V like yours. The Cam sensor on yours runs through the MAF sensor and then to ground like XLT mentioned. But it also runs a dark blue/orange stripe wire to terminal 85 of the PCM. On mine the Cam sensor connects directly to the ignition control module (ICM). It appears you don't have a ICM and the PCM does all the spark calculation within it's own little mind, so to speak. So the hardware is a little different but I would think the system desing is the same. On mine, you can disconnect the cam sensor and the car will still start/run. But spark is not optimized and you loose some spark advance. I would think you can disconnect yours too. If you get the same type of performance, then it's likely the Cam sensor is not helping you when it is connected.

Raw gas out the tailpipe seems simply impossible to me. That's an arduous trek for gasoline to make without completely evaporating in the process. Are you sure it's not carbony wate? The CAT makes water as a biproduct. It can loosen up any previous deposited carbon and make you think it's gas like.

On the codes - you might get the 300 code as a result of a bad cam sensor or cam sensor input. These are all part of the spark delivery circuit. So I would concentrate on that. There's a schematice here at the autozone web site.

http://www.autozone.com/servlet/UiBr...3d800ba9c7.jsp