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Unsolvable Explorer Rough Idle. Any OBD II experts?

Discussion in 'Under the Hood' started by Cashcrazy, October 26, 2016.

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    1. Tylers02

      Tylers02 Active Member

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      I knew I should of grabbed this for you
      [​IMG]
       
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    3. Cashcrazy

      Cashcrazy Active Member

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      My EGR tube looks good.

      I'll check on the lock sensor PID in the morning.

      That intake looks slightly different from mine.
       
    4. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      Tylors02, that looks like a later model than 2003. It has an EGRS instead of an EGR valve with a separate EVR. Also, there's no place to mount an IAC valve so it must have electronic throttle control. Are you using a later manifold on your 2002 Limited?
       
    5. Cashcrazy

      Cashcrazy Active Member

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      I couldn't wait...... neither of the programs show anything for the knock sensor. Where is it located?
       
    6. MostlyNewExplorer

      MostlyNewExplorer Member

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      I've got hunch it might be in your timing chains/tensioners. Have you pulled the oil pan to see if there are any plastic parts in there?
       
    7. Cashcrazy

      Cashcrazy Active Member

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      No I have not pulled the oil pan. I am going to start looking for another ride.
       
    8. MostlyNewExplorer

      MostlyNewExplorer Member

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      I thought about that when I found plastic in my oil pan, but I've got so many new parts on her it'd be a shame to let her go.

      Anyway, IF it's just a tensioner(assuming it's timing related), you can change that from the wheel well. If it's a broken guide(the nylon parts) then you have to pull the engine(the easiest way).

      The entire timing chain kit is around $75 for everything! BUT, the tool kit to keep it all aligned is around $250, give or take. For mine anyways.
       
      Last edited: November 5, 2016
    9. Tylers02

      Tylers02 Active Member

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      That is from an 05 4.0 at the junkyard. i no longer have the 02 I have an 04 now. Looks just like my 02 did with same specs 4.6l limited but awd instead of auto 4x4 and black leather instead of tan. I think crash has an 04 4.0 but I may be wrong.
       
    10. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      If you can't find the Knock Sensor Retard PID then you can just look at the Spark Advance PID to see if the spark acts unusual during engine idle. Spark Advance is the end result after the PCM extracts the value from the spark table and adjusts it for IAT, ECT and knock sensor retard.
       
    11. Cashcrazy

      Cashcrazy Active Member

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      I'll connect in a few minutes. I'm going to replace the one o2 sensor. It's obvious something is going on with the bank 2 downstream readings. I spent some time on google and there are people who have experienced failing o2 sensors with no code and a rough idle. Ill back into it from there.
       
    12. Cashcrazy

      Cashcrazy Active Member

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      Spark advance looks steady at idle. Bottom graph.

      [​IMG]

      I am going to go pickup the new sensor to throw a little more at my Briggs and Stratton idle.
       
    13. Cashcrazy

      Cashcrazy Active Member

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      New sensor in. The data seems to graph more smoothly with it but still fights the Briggs & Stratton syndrome. Graph below at idle.
      [​IMG]
       
    14. Cashcrazy

      Cashcrazy Active Member

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      The vehicle I was looking at was a bit of a drive away and sold before I could get there. So I guess it's ride or die with the Explorer once again. What's the next thing to throw money at?
       
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    15. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      What brand and type of spark plugs are installed? Did you check their gap and what is it?

      It's too bad the throttle plate wasn't wide open when you performed the compression tests. 150 psi is at least 30 psi low but that could be because the throttle plate was closed. All cylinders were comparable and it is unlikely both camshaft chains slipped to lower the compression. If the crankshaft to jackshaft chain slipped it would affect both banks equally but that is very unlikely since your 2003 has the improved primary tensioner and you have less than 75K miles on the engine.

      In the other thread your DPFE voltage looked reasonable at idle but you might try disconnecting the EVR (EGR valve regulator) electrical connector to see if that improves the idle. The PCM is supposed to disable EGR when the engine is idling. Disconnecting the EVR electrical connector should completely disable the EGR valve no matter what the PCM is trying to do. You can read the DPFE voltage again to see if it is the same as the previous reading.

      Did you try disconnecting the connector to the ignition suppression capacitor? According to the 2003 wiring diagram it has its own single pin connector (WH/LB wire). You don't need to disconnect the ground wire to the capacitor unless that's easier than disconnecting the single pin connector.

      I think someone mentioned the possibility of misfires affecting the idle. However, it seems to me that misfires should result in a detected lean condition because unburned fuel consumes less oxygen.

      There are not a lot of sources for a rich condition. The engine photo that you posted shows reddish colored injectors. My stock injectors were orange. I was unable to find used injectors listed on eBay for a 2003 Explorer flex fuel 4.0L vehicle to verify the correct color. Is there any reason for you to suspect that the original injectors have been replaced?
       
    16. Cashcrazy

      Cashcrazy Active Member

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      I am running Autolite double platinum plugs gapped to .055. I originally had them set at the minimum of .052, but moved to .055 hoping it would clear the idle up.

      I can try to disconnect the EGR valve. i don't recall unplugging the actual valve, but there was a EGR solenoid of some sort behind the intake.

      I have never heard of a ignition suppressor capacitor before. I will have to do more reading on this.

      The red injectors are listed on the rockAuto site. They are the factory injectors. I purchased the vehicle from the original owner.
       
    17. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      It should be easy to disconnect the electrical connector to the solenoid that controls the EGR valve. There is no need to disconnect the actual EGR valve.

      I mentioned the ignition suppression capacitor in post 36.
       
    18. Cashcrazy

      Cashcrazy Active Member

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      I'll try unplugging both of those this evening. I must have missed the capacitor in the earlier post. it would be great if one of these corrected the issue.
       
    19. Cashcrazy

      Cashcrazy Active Member

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      I unplugged both plugs at seperate times and no change.

      I want to touch on the O2 data once again. After installing the new sensor the bank 2 downstream reading is much more consistent, but the data begins to jump around during acceleration as shown below.
      [​IMG]

      Someone said this could be caused by a misfire on bank two and not a bad cat. I'm about to connect with a laptop and go for a drive to see what happens. The laptop software has a few more options and will hopefully have misfire data.
       
    20. Cashcrazy

      Cashcrazy Active Member

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      A little more testing with the laptop. The bottom graph is the knock sensor graph. I have no idea how to read this, but I believe I can see similarities between the downstream sensor graph. I was not going a steady speed in this test. I noticed while accelerating about 2500rpm bank 1 downstream would smooth out and bank two would jump around.
      [​IMG]

      I ran another test for misfires and the misfire cylinders changed
      [​IMG]
       
    21. Tylers02

      Tylers02 Active Member

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      Just a thought and I'm sure you are but you resetting pcm after changes? Also what scanner are you using in getting sick of being limited to torque
       
    22. Cashcrazy

      Cashcrazy Active Member

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      I'm using forscan and I have had the battery unhooked for hours so it should be reset.

      Autolab- I can now get the cab file. I'll email it to you after I gather all the data
       
    23. Cashcrazy

      Cashcrazy Active Member

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      I just sent Autolab a load of csv data. I hope he has a way to analyze this.
       
    24. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      The top and the bottom graphs look identical to me. What are the PID names and scale for the top and bottom graphs? Below is a graph of my knock sensor retard (red) while climbing a grade and increasing the throttle (green). The PCM adjusts the retard in increments of 0.25 degrees. You can see that at about 104.8 seconds the retard was +0.25 degrees but at the cursor (vertical double red line) it had dropped to -8.0 degrees. Also notice when there is a change in knock retard there is a corresponding change in overall spark advance (blue).
      KnockRetard1.jpg
       
    25. Cashcrazy

      Cashcrazy Active Member

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      PID names and limits below:

      RPM - 707/3788
      O2 B1S1 - .03/.95
      O2 B1S2 - .03/.93
      O2 B2S1 - .01/.95
      O2 B2S2 - .00/.89
      Knock - 36/167
       
    26. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      Since "Knock" tracks "RPM" I suspect the Knock PID is the number of knock sensor detections instead of the PCM computed timing retard. The PCM allocates a time slice of the crankshaft rotation for each cylinder's knock detection. As I recall there are user programmable calibration constants in the tune for the duration of the time slice and its offset from a crankshaft reference angle. There is also a sensitivity calibration constant and I think a threshold for each cylinder. There may also be a total count threshold for all cylinders in a revolution of the crankshaft. I suspect the latter is equivalent to the "Knock" PID you are plotting. A count of 167 could be less than the threshold and have no affect on the ignition timing. I'm only guessing because I don't have an additional SCT Advantage III tuning license for a 2003 4.0L PCM.
       

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