94 engine light question

[Runaway929]

This is my first post. I've been reviewing your forum for a few days now looking for some info but cant seem to find what I'm looking for. I've got a Check Engine Light that comes on a few minutes after I start the car everytime i start the car, and stays on. while I drive i can feel that there seems to be momentary losses in power-it comes and goes, but the light stays on. I've gotten the codes read once for $50 and they said it was nothing major and sent me on my marry way. (they didn't tell me what it read). The free places say that can't read my car. But I saw that a few of you have had the same problem and was wondering what you all found out it was so i can go right to it and be done. any info?

1994 90,000miles

 

[MrShorty]

"The free places say that can't read my car." -- This tells you how much they know. They probably could if they knew how. In any case, it's easy to read codes yourself, and doesn't require any expensive equipment. Then review instructions at www.fordfuelinjection.com (easiest to read), www.dalidesign.com/hbook/eectest.html (under tests, my personal favorite on the net), www.therangerstation.com (in the tech library), or any of the other websites that describes the EEC-IV tests. These instructions can also be found in any self-respecting repair manual. Pull the codes yourself, then post them here, noting which part of the test each code came from (KOEO, memory, KOER), and which parts of the test passed (111).

 

[Creager]

this probably isnt the same issue, but mine did almost exaclty how you described it

i would start the car, and after driving maybe 5-10 minutes down the road the check engine light would come on. Shoot, sometimes i would get to my destination with out it even turning on. It would scare me sometimes, i would be driving at night an BOOM i get this quick blinding from that little light. haha

well i drove around with that light on for about 2 years and it never hurt anything. I just found out what it was recently when i had to drop my exhaust y-pipe to swap in a new tranny. The wiring harness for my o2 sensor was destroyed and was clocking a code. I bought a new 02 senor all togeather (50 buck from advanced AR!) and boom, havent seen my check engine light since

Old OBD-1 technology is notorious for the 02 sensor being the root of the check engine light. newer OBD-II (96+ newer), usually has nothing to do with the 02 sensor.

 

[monkeydude3]

I had a similar experience and it ended up being my DPFE sensor. About $40 from parts city, as opposed to $100 from Ford. And my engine light has stayed off since. Yeah as previously posted there are ways to make your engine light flash the code. Costs you zero dollars but a few minutes of time.

George

1994 XL 4.0L OHV 5 speed manual 2wd

 

[Runaway929]

does the 94 explorer have a DPFE? I thought it was only a PFE sensor. thats what I'm reading in the manual anyway...I think it is this sensor (one of them). and would it be called something else? I went to 3 auto parts stores and none of them had it in there system (the DPFE) could that be because it doesn't exist for the 94? BUT I called the ford dealer and they had one and said it cost $139 and but wouldn't tell me anything else...they were busy. I'm confuzzed...

 

[Runaway929]

okay, the KOEO test shows 335, the memory test shows 157,327,332. I can't seem to figure out just yet how to do the running test by myself. but thats what I have so far...help?! seems to be pointing to the EGR system.

 

[MrShorty]

Correct, it is pointing to the EGR system, at least as a start. SOP is to resolve KOEO codes first, so we start with the KOEO 335. Note that KOEO codes almost have to be electrical, because they are set with the engine off. In order to avoid replacing parts unnecessarily, be sure to inspect the wiring between the DPFE/PFE and the computer. If the wiring checks out, then the DPFE/PFE is probably bad.
As for a supplier, I'm pretty sure most parts stores will carry it, but they may not be smart enough to know that it can go by many names: EGR position sensor, EGR valve sensor, EGR sensor, EGR pressure sensor, and so forth and so on.

 

[Runaway929]

is this sensor the one w/ the 2 hoses and a wiring harness w/ three connection on it? sort of a little rectangle box? sorry to sound crued, but there are no pictures of it in my haynes manual. thanks for all your help so far.