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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 mean what adapter. Mine is a eBay elm and the only program it seems to work with is torque. Tried to upload some pictures of my reading but carputer died and don't have torque on my iPhone. Not sure it would help as I can't graph nearly as much as you can. My 02s during idle look identical to yours but both bank 1 & 2 sensor 2 flat line on idle haven't had a chance to graph at different rpms. Just throwing it out there maybe try the pcm reset sequence for the heck of it. Believe after battery has been disconnected make sure all accessories are off turn key to run until you here a certain amount of chimes. Then start it and go though all the gears and then back to P.
       
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    3. Tylers02

      Tylers02 Active Member

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    4. Cashcrazy

      Cashcrazy Active Member

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      I am using a WIFI ELM I bought off ebay. I'll try another reset.

      So I was about ready to order three new injectors to replace Bank 2 to see what happened, but after running the last test Cyl 1 & 3 show the misfires which is the opposite bank. I am not sure .16% is enough to even notice. did the flex fuel get a different injector that could cause this? Ethanol to gasoline seems like a wide swing to run well on either fuel.

      Is it possible to see what software version I am running without going to Ford? I was told by the Ford service center about a year ago that I am running the latest version, but would like to check this for my piece of mind. There is a thread here about a ECM update clearing up rough idle. It seems like all of the sensors and everything mechanical is functioning as it should. I think I have tested everything a mechanic would and the labor hours alone would be worth more than the vehicle.

      I have a couple of side notes... The used SUV I was looking at sold before I could make the drive so it looks like I'll continue to ride or die with the explorer. While looking at fuel additives a bottle of octane booster caught my eye. The rough idle does feel like a ignition problem so I thought why not, I've tried everything else. I'm running it now and have not noticed a difference. Maybe I'll try 93 octane on the next fill up. Id try ethanol at this point, but I haven't seen a station with it for sale in years.
       
    5. Autolabs

      Autolabs New Member

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      I think we need a refresh of your symptoms. What is 'rough idle' to you? What does it feel like in your best descriptive terms? Is the AC off?
      I'd hold off on purchasing injectors right now. B2s2 is crazy at higher rpm and steady at idle which shows inefficiency and not so much a slight misfire, it just can't scrub a higher flow of exhaust. Looking at your log your rpms are pretty steady. 5.4 gm/sec @ 730 rpm is a bit high compared to an O2 ranger 4.0 that I have on file which is about 4.5 gm/sec @ 730 rpm. Does it look like the throttle stop screw has been messed with?
      I would also call around some shops and just get a price to perform IAC test to see how snappy the rpm changes throughout the duty cycle ranges. Should only take 5-10min from hook up,test, and unplug.
       
    6. Autolabs

      Autolabs New Member

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      Oh and besides snappy rpm response, look for uniform rpm change per 10 percent increments commanded by the scanner. And have you tried unplugging the alternator yet to eliminate AC ripple in the electrical system?
       
    7. Cashcrazy

      Cashcrazy Active Member

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      I will try the alternator this evening. Nothing looks tampered with under the hood.

      Ill do my best to describe the rough idle. I have wrenched on carbed vehicles for years doing everything up to a frame-off. The rough idle is with a warm engine with the AC on or off, but the AC tends to amplify the issue. The roughness is very noticeable in park or neutral. There are times when I am sitting at a red light in drive and I cant feel the engine running but after several seconds I start to feel the roughness. The problem is not noticeable when I first start it, but the RPM's are also higher during warm-up so its not a fair comparison. Many words can describe this such as missing or sputtering. Around 800 rpm seems to be when it really starts missing. You can feel it in your feet and in the seat. Now for a mechanical comparison. I was working on an old inline 6 about a year ago. It had a random miss or cough that I couldn't get rid of. The old ignition system was severely outdated so I swapped in a MSD box and higher voltage coil. The idle was better, but I still had the miss so I slowly gapped the plugs wider(new coil allowed this) and the miss finally disappeared. What I am experiencing with the Explorer feels like this only its happening repeatedly. Id be happy will an occasional miss. My wife sat in the car with it idling for about ten minutes and claims it made her nauseous. I wish one of you were closer and Id drive it and let you experience first hand. I might even take a road trip if the Ford master could solve this.

      What can cause the B2S2 to go crazy at a higher rpm? I've watched videos online and other cars have a smooth line with their downstream sensors.
       
    8. Cashcrazy

      Cashcrazy Active Member

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      Also, I know you have mentioned using a Motorcraft brand IAC. The one I am using was in a BWD box. I also went back and swapped in the factory IAC and there was no change. With that said I really hate to throw the cash at a new Motorcraft IAC.
       
    9. Turdle

      Turdle I bake stuff Staff Member Moderator Elite Explorer

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      If it seems like a mis fire, you can remove spark plug wires from the coil pack with the engine running to help identify which cylinder is not firing correctly.

      You do have to pull em off quickly, and don't let a finger get lower than the cap or the coil might bite ya. It only hurts for a second though.

      If you do it right, you can pull them off the coil and put them right back on with no bites or worries.
       
    10. Cashcrazy

      Cashcrazy Active Member

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      Turdle - I swapped the coil pack out with a Motorcraft one from the junkyard as a test. No change. I could also hear the wires trying to arc when doing the compression test. I can pull the wire off the plug and see if it runs differently, but if it's not the coil pack then what can cause this? Isn't the spark controlled by the ECM??
       
    11. Turdle

      Turdle I bake stuff Staff Member Moderator Elite Explorer

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      Not doubting the coil pack at all, I was just trying to narrow down which cylinder is mis firing. It could be caused by lots of things. But that would be speculation at this point.
      It could be bad spark plug wires, spark plug, fuel injector, fuel injector wiring, Wiring from the PCM, Timing chain jump, etc.

      If the engine is running rough, and a plug wire is removed from the coil pack with no change, you have found the mis firing cylinder. If a cylinder is misfiring at random, the cylinder which shows the least amount of change when the wire is pulled, is the one to start looking at.

      If you have a pulsing vacuum gauge reading, there is most likely a mis firing cylinder. It will have a rythm to it. You can find the cylinder using the vacuum gauge combined with the tachometer, while cutting spark to a cylinder to help identify which cylinder changes the engine speed less when cut.
       
    12. Cashcrazy

      Cashcrazy Active Member

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      Just a little more description on the idle. It doesn't have a rhythmic pattern. It seems to come in constant waves like a shiver.
       
    13. Cashcrazy

      Cashcrazy Active Member

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      Turdle - I'll hook up the vacuum gauge to manifold vacuum and pull one wire at a time. With the wire off the vac gauge should start to pulse? I want to make sure I am testing correctly. I connected the gauge to the fuel injector pressure damper hose and had a very steady reading before. I can connect to the same hose and watch for change.
       
    14. Cashcrazy

      Cashcrazy Active Member

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      One last idea for the day. I can go pull an ECM from the junkyard for testing but swapping these out is beyond my knowledge of how it will effect other systems. It looks like the brains are located on the passenger side behind the kick panel. Is it as easy as pulling a test subject and swapping them or are these VIN specific needing to be paired with the transmission? I usually look on rockauto to see what years parts are interchangeable but the computer is not listed. I am assuming 2002-2003 are the same since I have seen sensor changes starting in 2004. Does anyone have any information or thoughts on this?
       
    15. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      Swapping the PCM will requiring reprogramming it to recognize your existing PATS ignition keys. I don't recommend it. After swapping the PCMs you would have to tow the vehicle to a PATS qualified locksmith or the dealer for the reprogramming. Reprogramming the first two keys takes about 15 to 20 minutes for each key and a special machine. It would cost around $75 at a locksmith.
       
    16. Cashcrazy

      Cashcrazy Active Member

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      Thank you exactly what I needed to know. Probably my last idea of the day. I didn't overly inspect under the valve covers when I had them off but nothing jumped out at me either. Is there anything with the rocker arms or push rods that could cause this or would that throw a code. Maybe a push rod off the lifter. In a Chevy v8 it would cause a it to run rough off idle also, but I don't know if the computer will Change the fuel flow to compensate in this motor. Just throwing something new out there.
       
    17. Autolabs

      Autolabs New Member

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      TPS volts at idle 1.04. Are you able to see a PID showing either c/t or p/t? I would like to see c/t TPS volts to be a little lower. Can you adjust your TPS? You also said when you 1st replaced your IAC that it stopped stalling. So is it possible you have a failed oem and an under performing aftermarket one that your testing with?
       
    18. Cashcrazy

      Cashcrazy Active Member

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      Anything is possible but there was no noticeable difference between the two. Maybe I should just unplug it to see what happens. What is the c/t and p/t PID and I will look? I unplugged the alternator and AC compressor with no change. I'll check out the tos tomorrow.
       
    19. Autolabs

      Autolabs New Member

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      C/t and p/t stands for closed and part throttle. The pcm gets its c/t voltage at start up assuming you aren't pressing the gas.

      One more thing, due to the low mileage and age, I suggest you call around for a professional motor vac or top engine cleaner. A bit pricey but well worth it. Much better than anything you could poor in the tank. Fuel additives are more of a 'keep it clean' rather than a good carbon scrub.
       
    20. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      After the 1st Generation Explorer there is no longer a need to adjust the TPS closed throttle voltage. There is a routine in the PCM that measures the TPS voltage when the ignition is switched on and assumes that voltage is for a closed throttle. It uses that voltage as the reference but periodically checks for a lower voltage. If one occurs then the PCM makes that the new closed throttle reference voltage.
       
    21. Cashcrazy

      Cashcrazy Active Member

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      I've thought about running some marvel mystery oil with the oil for a couple hundred miles. I have had that cure lifter tick in some prior dirty old engines
       
    22. Cashcrazy

      Cashcrazy Active Member

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      I'm showing that I have a "Fuel Pressure Regulator" that is Dorman part number 911260. Is this located somewhere that is accessible without dropping the tank and could this cause the rich condition?
       
    23. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      The fuel pressure regulator is in the fuel tank and your fuel pressure is normal.
       
    24. Autolabs

      Autolabs New Member

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      If you don't want the motor vac, at least 'smoke it' with sea foam a couple of times. Google it and see if your up to it. Note that motor vac can also clean up convertors for inefficiency issues as well.
      As far as your tps voltage, does your closed throttle voltage stay constant after opening the throttle and closing it a few times?
       
    25. Cashcrazy

      Cashcrazy Active Member

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      The tps sensor always returned back to the same voltage when I tested it awhile back. I will have to google the motor vac and try to find somewhere that has the equipment. I like the idea of clearing out carbon and clearing the converters.
       
    26. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      Be careful using Sea Foam if you plan to add it thru the vacuum system. If fed very rapidly it can pool in the combustion chambers and lock the engine from rotating. Also, some members have to replace their spark plugs after an intake manifold Sea Foam treatment because the loosened deposits foul the spark plugs.
       

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