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Trouble codes?

djd

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Joined
October 21, 2012
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City, State
Lincoln, NE
Year, Model & Trim Level
94 Explorer, 4.0, PushRod
I drug home my first Ford ever for $350.00, 94 Explorer, 4.0 push-rod engine. I was told it wouldn't start. I charged the battery, turned the key and it started but with a serious engine miss. Now, a year later, finally got around to it. New battery, removed spark plugs, cyl 2 wet & smells like gas, all others look OK. Compression test, all cyls 135-140. Plug wires Ohm out OK. 1 freeze plug on each side of block missing, installed new. filled with water, let run to operating temp. Still misses. Has CEL but don't know anything about fords. Revving engine in park seems very sluggish. Found thread for CEL with wire, will check this later. What is best engine analyzer for this? Don't want to spend too much money just yet. Eagerly awaiting all responses.

Here are a couple links I found for the trouble codes. On the first link, at the bottom of the page there is a link button "Diagnostic Trouble Codes" which will actually take you to the second link.
http://autorepair.about.com/library/a/1i/bl804i.htm

http://autorepair.about.com/cs/troub...l_dtcs_54a.htm

I will be using this information to help trouble shoot my new 94 Explorer project.

OK Explorer Experts Here are the trouble codes in my X project; 327, 327, 1, 172, 327, 543. The internet link mentioned above say that the first codes are an "On Demand or Hard code" separated by the "1" and then the "Continuous Memory Codes". Don't know yet what the difference is. The first code, which appears in both sets, is 327, PFE sensor circuit voltage below self-test minimum. What is the PFE sensor? Next is 172, HEGO sensor circuit indicates lean. What is the HEGO sensor? And lastly, 543, Fuel pump circuit open, battery to EEC processor. I'm not sure about the last one for the fuelpump circuit being open because it starts and runs.

Need your comments!
 






The internet link mentioned above say that the first codes are an "On Demand or Hard code" separated by the "1" and then the "Continuous Memory Codes". Don't know yet what the difference is.
You might review my "notes on pulling EEC-IV codes" thread in the EEC-IV forum, where I discuss the difference between KOEO and CM codes.

SOP with these is to resolve KOEO codes first (on demand or hard codes), then resolve KOER codes (they didn't describe the KOER test), then resolve any remaining CM codes.

What is the PFE sensor?
PFE = Pressure Feedback EGR, it is the sensor used to monitor and control the EGR system. Since KOEO codes are set with the engine off, they almost have to be electrical in nature. Considering the issues these sensors have, I would probably inspect the wiring between the PFE sensor and the PCM and, if all checks out ok, replace the PFE sensor.

Next is 172, HEGO sensor circuit indicates lean. What is the HEGO sensor?
HEGO = Heated Exhaust Gas Oxygen. Your '94 has 2 O2 sensors, one for each side of the engine, so review the code list to see which side a 172 refers to. Some consider O2 sensors a maintenance item, so, if it has been a long time since they've been replaced, you might try replacing the O2 sensors to see if this resolves the issue. Then, if it doesn't go into a more detailed diagnosis. You could also try swapping left and right O2 sensors to see if the code follows the sensor or not, which should give a good indication if the sensor is faulty or if it is something upstream. As a CM code, I'd probably start by clearing CM and see if this one comes back (or how quickly it comes back) to give some idea of how consistent this fault is. A KOER test could also be useful in diagnosing O2 sensor codes.

543, Fuel pump circuit open, battery to EEC processor. I'm not sure about the last one for the fuelpump circuit being open because it starts and runs.
As a CM code, this could be an old code. I'd probably clear CM and see if this one comes back. I will note that for a long time I would get an intermittent CM 543 which I couldn't resolve until that morning the break in the fuel pump circuit got bad enough to prevent me from starting the engine. Intermittents can be hard to diagnose until they become bad enough to cause other problems.
 






Thanks a bunch!!! I'll try this over the week end.
 






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