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Starts, then chugs, loses power, Check Engine Light; only 2 cyl firing

Discussion in 'Stock 1991 - 1994 Explorers' started by mrbarnard, March 4, 2014.

^^Searches ExplorerForum.com^^





  1. mrbarnard

    mrbarnard New Member

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    Still trying to get my 1992 Ford Explorer 4.0L 4dr Auto 4WD VIN X to run properly.

    Here's the current situation:

    It starts fine, runs about 30 seconds, then chugs, loses power, and Check Engine Light comes on.

    What we've discovered: It is running on only 2 cylinders now. When I pull the the wires off the coil, here's what I find: Cylinders 1 and 5 do not spark at all. Cylinders 2 and 6 spark but do not fire. Cylinders 3 and 4 spark and fire.

    When I first got this Explorer, the engine ran fine. These problems occurred after it failed a smog test. (It probably would not have failed had anyone noticed that a 1' piece of tailpipe was missing between the catalytic converter and the exhaust pipe, which I've since installed). After making many attempts, codes were pulled but were random so I replaced O2 sensor, crankshaft position sensor, MAF, cleaned the Idle adjust sensor, replaced vacuum tubes, repaired a few broken ground wires, re-installed the 'retard timing' octane jumper.

    I base the cylinder numbers on this diagram:

    3 4 -- sparking and firing
    2 6 -- sparking, not firing
    1 5 -- no sparking, no firing
    (Coil looking from the front)

    Cylinders on the engine are numbered
    3 6
    2 5
    1 4
     
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  3. FR-425

    FR-425 Used to be a road here. Elite Explorer

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    Coil pack is bad, or the Ignition Control Module (ICM)

    Your getting spark on 2 & 6 but obviously at the wrong time. But 3 & 4 are ok, which leads me to suspect the ICM.

    However:

    What codes did you get? I ask because you mentioned "random" codes.

    Random unrelated codes are an indication that the PCM has failed.

    If you get or ever got a 513, the PCM is dead. 513 = Internal voltage failure.

    Pull the codes again and post em up for a look.
     
  4. mrbarnard

    mrbarnard New Member

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    THANKS

    I can't really make out the pulled codes from the invoice, but maybe they make sense to you: http://postimg.org/image/qvczrk9l5/

    I tried to test the ICM, but not sure if I did it correctly. I unplugged the ignition coil and used a test light, neg to battery and probe to the Yellow/Black, Yellow/Red, and Yellow/White pins, then cranked the engine. The probe light never lit up (I tested the probe directly across the battery and the light lit up).

    I am not comfortable about having done it right, since there was NO response from the probe. Since 2 cylinders fire, 2 cylinders spark, and 2 cylinders do nothing, I would suspect that the probe should have indicated something like that, instead of no response to any pin. But, I may be wrong, of course.
     
  5. FR-425

    FR-425 Used to be a road here. Elite Explorer

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    Ok,

    I can make sense of those codes. Believe it or not!

    WTH kinda chicken scratch is that! :wtf:

    Anyhow; codes 411 & 412 indicate that the KOER test was not run correctly (DUH)

    341 just means the octane adjust bar is removed (not a problem)

    232 = Spout circuit grounded

    212 = ICM circuit 1,2,3 or 4 failure.

    Diagnosis = ICM is shot. :shoot:

    It is located in front of the battery mounted to the core support next to the radiator.

    Remove the battery to gain access.

    Recommend replacing the coil pack as well, It may have caused the burnout of the ICM.

    RockAuto has them: :thumbsup:
    https://www.rockauto.com/dbphp/x,ca...RER_4.0L_V6_Ignition_Control_Module_ICM_.html

    Looks like this:

    [​IMG]

    I gather you already know this, just being thorough.
     
  6. mrbarnard

    mrbarnard New Member

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    THAT WORKED. Thanks. Replaced the ICM and the engine runs smoothly.

    (Now trying to get it smogged, they said it surges above and below acceptable NOX, so now I need to track down THAT problem ... vacuum leak or EGR or whatever. Damn.)
     
  7. FR-425

    FR-425 Used to be a road here. Elite Explorer

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    :salute: Your quite welcome.

    NOX would be the catalytic converters need to be replaced. (in the absence of a Check Engine Light)

    That's what they do. Scrub Oxides of Nitrogen from the exhaust.

    If your really close on the numbers though you can cheat a bit.

    If you can get the engine to run hotter during the test it may pass.

    It would be a good idea to pull the fault codes even if you do not have a CEL.

    The EGR system does play a roll here. You may just have a intermittent fault. And no CEL

    And I know what it will be already. :shifty_ey

    The DPFE sensor. You will probably pull codes in the range of 328 through 338 all related to the same thing. The DPFE sensor.

    Here it is: Not expensive $50 lifetime warranty. :thumbsup:

    [​IMG]

    Double check these hoses, make sure the smaller tube (front) is on the upper exhaust reference tube, like the picture. Check that they are in good condition (no cracks nice and tight) If you need to replace the hoses use high temp silicone only. The AP store will have them as a kit at the counter.

    May as well just replace this thing; your truck will thank you!

    If it still won't pass then the cats gotta go.
     
  8. mrbarnard

    mrbarnard New Member

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    Can't find the DPFE ("EGR Valve Pressure Sensor"?)

    Thanks, again. I just now am back in town, desperate to get the Explorer smogged and licensed.

    The DPFE Sensor is VERY difficult to find and identify on my 1992 Ford Explorer XLT 4.0L. It doesn't exist as shown in your photo, and the online research I've done has been sketchy at best. I found this at AutoZone, which calls it "EGR Valve Pressure Sensor": http://www.autozone.com/autozone/re...epairGuideContent.jsp?pageId=0996b43f802c54a8 (AutoZone says this is the part: http://www.autozone.com/autozone/pa...WD/_/N-iwpxxZ93xpy?itemIdentifier=135992_0_0_) but the diagram for the 4.0L does not match what I see under the hood of my Explorer. There is nothing in the area described by the diagram as a tube coming from the exhaust manifold, and nothing that looks like the picture you posted. Here's what the engine looks like on the drivers side: http://s20.postimg.org/a1s1xz7gt/possible_EGR_valve_nothing.jpg

    I wonder if THIS might be the valve? http://s20.postimg.org/7lq8k4pe5/possible_EGR_valve.jpg (close-up: http://s20.postimg.org/onj2m8499/possible_EGR_valve_CU.jpg)
     
  9. teletekman

    teletekman Member

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    That is actually your Fuel Pressure Regulator. The 92 Ex did not have an EGR Valve. I don't think they started including one till 93. If your seeing high NOX on your smog report then as FR-425 stated, your cat is probably shot.

    I just went through this exact same thing last month having to smog mine. All numbers looked great except my NOX which was huvering around the 800+ range on both 15 & 25mpr tests. Changed the cat and numbers were in the teens at both speeds. :thumbsup:
     
  10. FR-425

    FR-425 Used to be a road here. Elite Explorer

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    x2 teletek is right 92's rarely found with EGR.

    Since you are in Cali I was guessing that yours just might.

    So yes the cats need to be replaced to fix high NOX.
     
  11. teletekman

    teletekman Member

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    Just to add a note, I bought my cat at Pep Boys for about $225 and changed it out myself. It is not hard at all to do yourself. Only thing I would recommend is dousing the flange nuts and bolts on both ends with PB Blaster and letting them soak over night. Plus is you have air tools it makes everything a whole lot easier.

    Only other thing you will need to do is cut the "Y" pipe at the flange to where it sticks out about 1/2". That way it has plenty of clearance for the aftermarket cat. If you can get hold of a sawzall the whole job should take you about an hour or so.

    http://www.pepboys.com/product/details/9924594/668/

    Plus when it's all said and done, take your cat and recycle it. I got $70 bucks for mine which in the end, the whole job cost me about $160. Not bad considering the $400+ I was being quoted at the muffler shops.
     
  12. mrbarnard

    mrbarnard New Member

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    THANK YOU, teletekman and FR-425!

    I thought I'd lost my abilities, so it's good to learn there is nothing there to find. Whew.

    On the other hand, replacing the cat is MORE money and it's killing me financially. But your suggestions about how to DIY it will help me a lot. (As will simply determining this is the solution and not spending more time trying to track it down. It's been a LONG and frustrating time trying to get this Explorer running and legal.)

    Thanks.
     
  13. FR-425

    FR-425 Used to be a road here. Elite Explorer

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    Not sure how they handle Cats in the bone yards in Cali, but you may be able to get some "better" ones for cheap that way.

    Out here most of the JY's pull them first thing and recycle the Platinum rather than sell the units used.
     
  14. teletekman

    teletekman Member

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    All the boneyards here make it plain and clear that they will not sell any cats as it's against commiefornia law. Too bad cause recycling them pays pretty good $$$ here.
     

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