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Explorer won't start


New Member
May 4, 2013
Reaction score
City, State
Pasadena, CA
Year, Model & Trim Level
1993 Explorer XLT
Hi I have a 93 xlt and for a while now it has been having troubles. When the engine is warm it will accasionally would have a rough idle and as time progressed the troubles have gotten worse. When i would sart it up cold initially it seems to have some throttle lag and takes a second to kick in and when i start it when its warm it has a rough idle and takes a very long time to become responsive, plus today pulling on to the freeway it could barley get up to speed. So any way when i pulled out my driveway it just died and wont start. I have pulled codes a few times and just pulled them after this getting 186 335 336 337 with the engine off, it seems to me like its the dpfe has this happened to any one? Does any one know where the problem is?

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Welcome to the forum!

The DPFE can fail, but generally symptoms are very minor and it won't cause a no-start. Does sound like yours has failed at some point. They are very easy to replace and don't cost too much, about $40 on RockAuto.

You can try swapping just the DPFE or checking for electrical faults related to it such as wire damage, but I doubt that will fix your no-start. The code 186 sounds like a clue that your problem is fuel-related.

Check your MAF; I wouldn't suggest throwing parts at it, but see if it runs any better (or starts) with the MAF unplugged. Unplugging the MAF forces the PCM to use speed density and guess at the necessary fuel to inject for what air it thinks is coming in. Sometimes this will work if your MAF is truly bad.

Check fuel pressure, this I am thinking is more likely. A fuel pressure test gauge is available at most parts stores. It screws onto the test port on your fuel rail (no parts removal required) and reads the fuel pressure at the rail. When you turn the key ON (without starting) the pump should run momentarily and prime (pressurize) the system to about 30-40 psi. This pressure should stay and take at least 20 minutes to leak down. This tests that the fuel pump is putting out enough pressure to prime the system, and that the fuel pressure regulator is regulating the pressure to the proper level and holding it tightly instead of leaking. It also tests if the injectors are closed, as they should be, and holding pressure. Once you start the engine you can read fuel pressure the same way; the reading will fluctuate somewhat but you should see the pump keeping up with demand.

The code 186, Injector Pulse Width Longer Than Expected, indicates that the PCM is commanding the injectors to stay open for an abnormally long time. The PCM will try to feed the motor enough fuel, but if fuel supply is too weak, it has to open the injectors for longer and longer to try to cope. Or, if the PCM is erroneously told the engine is running lean (too much airflow is reported due to a malfunctioning MAF) it would dump extra fuel to try to compensate for what amount of air it is told is coming in, and it will run the engine rich. I doubt the latter is your issue; it sounds to me like a failing fuel pump. The PCM has no way of knowing that the pump is failing and simply tries to open the injectors longer to feed the engine enough fuel.

If the pump is truly to blame, never fear, it is not too terrible a job and does not require dropping the tank unless you want to. You can cut an access hole in the body and change the fuel pump through there.

Before throwing any parts at your problem, such as a MAF or fuel pump, please try the fuel pressure test and MAF disconnect that are described above, and let us know how it goes.

alright so after letting the engine cool down for like 20 mins it started back up. i have only been driving a little bit after that but it seems to be running fine. Also could heat be to blame because it seems that as the weather has gotten hotter it has been running worse. I will definatly look into renting a tester from oreillys or someother place to see if thats the problem, and if thats the case it would be the third time ive had to drop the tank (2 failed attempts to repair my float) so the job should be a no brainer

It is sounding more and more like your fuel pump is shot.

When a fuel pump wears out, it gets weaker as it heats up and at a certain point will get hot enough to just stop pumping at all. Sometimes having a full tank of gas helps because the extra fuel cools the pump well enough to keep it running. But in most cases it will simply pump fuel for a while, get hot and quit. Once you let it cool off, it will usually pump fuel for a little while again.

Had two different cars with fuel pumps fail, many miles from home. I would drive a few miles till the failing pump stalled the engine, let the pump cool, then drive some more. Lots of short hops later, both times I made it home.

Update: so because my explorer had been sitting for along time before i started driving it like a few months ago i got the suggestion that it could have water in the tank? anyways so i got a bottle of some stuff that will dilute the water with the gas and filled it with premium. Since then i have put about 100 miles on it and it was good for awhile and but i still had the problem when the engines warm. Alot of the time when i start it up when the engines hot it will have a bad idle and when i give it gas nothing happens or it will barley move and after maybe like 30-60 seconds later it will begin to regain power but still run crappy for a bit. I am strongly considering testing my fuel pressure but still haven't gotten to it yet. Also what does the fuel pressure regulator do, i have done some research on here but still cant find much

and so far i haven't had it die on me so i hope that's a good sign

Fuel pressure regulator... regulates the fuel pressure! :)

First imagine it acting as a one-way valve for the fuel the pump sends to the fuel rail; pressure is maintained in the rail once pumped up, and it should stay for a while. A diaphragm inside the regulator does this and seals, holding that 30-40psi of pressure in the rail instead of leaking back toward the pump if the pump stops running. Also, it regulates the pressure by blowing off pressure at a certain point using a calibrated spring. The excess pressure is bled off back to the fuel tank. Factory regulator is non-adjustable, but aftermarket ones have an adjustment to preload the internal spring and raise or lower the pressure the spring puts on the diaphragm. A vacuum line connection to the regulator gives it a "reference" to cope with varying fuel demands.

Or, check out Ford's description of the regulator.


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I would strongly urge you to check out the fuel pressure situation as soon as you can. Running an engine lean is never good for it.

Using a fuel pressure gauge will quickly help diagnose fuel pump and pressure regulator problems.

Thanks so much! I will get to renting the tester asap

After you rent it, feed the hose and the gauge up between the hood and firewall, tape or ty-wrap the gauge to the antenna so you can see it, then drive around some. Your pressure shouldn't fall below 30 under any load conditions. Regulators do fail, but from reading the forums, it's usually always the pump.

And I gotta throw this out - swap the A/C relay with the fuel pump relay (same part). Your pump relay may be hanging up when heating up. This too is unlikely, but worth a try.