Unsolvable Explorer Rough Idle. Any OBD II experts?

[Tylers02]

I knew I should of grabbed this for you

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[Cashcrazy]

My EGR tube looks good.

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

That intake looks slightly different from mine.

 

[2000StreetRod]

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?

 

[Cashcrazy]

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

 

[MostlyNewExplorer]

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?

 

[Cashcrazy]

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

 

[MostlyNewExplorer]

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.

 

[Tylers02]

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.

 

[2000StreetRod]

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

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.

 

[Cashcrazy]

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.

 

[Cashcrazy]

Spark advance looks steady at idle. Bottom graph.

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

 

[Cashcrazy]

New sensor in. The data seems to graph more smoothly with it but still fights the Briggs & Stratton syndrome.

 

[Cashcrazy]

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?

 

[2000StreetRod]

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?

 

[Cashcrazy]

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.

 

[2000StreetRod]

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.

 

[Cashcrazy]

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.

 

[Cashcrazy]

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.
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.

 

[Cashcrazy]

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.

 

[Tylers02]

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