Unsolvable Explorer Rough Idle. Any OBD II experts?

[Cashcrazy]

I found a website that I have never stumbled upon before in my hours of searching.

https://www.picoauto.com/library/case-studies/2002-ford-explorer-4-0-v6-intermittent-misfire

 

[Tech By Trade]

Huh, bad lifter.... Could be. That will be a fun fix.

 

[Cashcrazy]

Huh, bad lifter.... Could be. That will be a fun fix.

It is possible since I have tested or replaced everything external. I am curious on the number of hours that is estimated for a mechanic to fix, but the value of the vehicle is probably not worth the repair.

 

[MostlyNewExplorer]

Did you replace/check the ECT on the thermostat housing?

 

[Cashcrazy]

Did you replace/check the ECT on the thermostat housing?

I didn't replace it but I monitored the coolant temp via OBDII data and it seemed very reasonable. The coolant temp stays around 190.

 

[Tech By Trade]

Do it yourself, It wouldnt be that big of a job, no worse then fixing a broken spring. Hardest part would be confirming which one, if any it is, without that fancy tool that fellow had.

 

[Cashcrazy]

Do it yourself, It wouldnt be that big of a job, no worse then fixing a broken spring. Hardest part would be confirming which one, if any it is, without that fancy tool that fellow had.

I spent a few minutes googling the tear down and haven't found a thread yet. I can hopefully find something.

 

[Tech By Trade]

Pop the valve cover, compress the spring, pull the rocker, pull the lifter. Easy peasy. Gotta find out which one is the issue first though.

 

[Cashcrazy]

Pop the valve cover, compress the spring, pull the rocker, pull the lifter. Easy peasy. Gotta find out which one is the issue first though.

Do these need a special compression tool? I've pulled valve springs on old Chevy's, AMC's, and jeeps but not the overhead cam design. does it have two lifters per cylinder?

 

[Cashcrazy]

I was backing out of the driveway this morning and the explorer surged two or three times. I'm not sure how it didn't die, but it didn't, I haven't had this surging in reverse issue since the beginning of this journey and it finally threw a code! Do these mean anything to anyone?

 

[Tech By Trade]

There is a special tool, but I'm sure with a little effort a guy could rig something up to do just one.

 

[MostlyNewExplorer]

I think you have a short somewhere in the harness, possibly between the ignition switch and the cruise control.

Have you ever seen a little puff of smoke come out of the steering column? or maybe a crackling sound?

 

[Cashcrazy]

Never seen or heard either of those

 

[MostlyNewExplorer]

It could still be a short somewhere in the harness. I'd start by checking the obvious/easy to get to places. Then look for anything that's been taped, and anything that looks wonky.

You should check the plugs for the harness first from the PCM to everything under the dash/steering column. My explorer has a plug in the back in the compartment where the jack is located, I'd check that too if you have it.

 

[swshawaii]

^ Ditto. IF you have a tilt column, move it up and down several times leaving it all the way UP. There is a common and known wiring issue with Gen 2/3 steering column harnesses that were too short from the factory and cause intermittent problems. Although it usually affects the Multi Function Switch (MFS) wiring, the ignition switch "may" also come into play. It will only take 10 seconds to try, after all this thread is at 214 replies and still counting. GL

http://www.mysporttrac.com/MySportTrac/projects/Steering_Column_Wiring_Repair_Gen1.pdf

 

[Cashcrazy]

I'll check it out. I cleared the codes and will see if they come back.

 

[Cashcrazy]

I rounded up all the extra parts from this project to get out of the garage. This would be a cheap way to have extras to test parts. Send a msg if anyone is interested. Would make a good deal on the lot.


1 - New WIX auto trans filter
1 - Used Ignition Coil
1 - Used Crank position sensor
1 - Used MAF sensor
6 - Used fuel injectors
2 - Idle air control valves/sensors. One is the factory one removed and the other was used year.
1 - New Fuel injector adapter. You will probably have at least one break if you are replacing injectors.
1 - Used cam position sensor
1 - New EGR valve gasket
1 - New EGR tube oring
4 - Used fuel pressure regulators (dampers). These are $300 each if purchased new.
2 - New Purolator oil filters (not pictured)

 

[field]

Hi 2000StreetRod,

Here is the question.
The plenum, where the air goes, control dial goes clockwise from MAX A/C at 7 on up to OFF. Then from 'upper and lower' air at 11 on down to defrost at 5.
Two mechanics have shown me that my engine idle speed oscillates when ever the pointer points to the right side points and idles smoothly whenever I chose the left or A/C side points. They say the right side choices always turn on the A/C even thought I actually get A/C from the A/C point when the pointer points to A/C on the left side. And I actually get heat when choosing the points on the right side.

Listening to the engine, confirms the A/C clutch seems to engage, whenever the dial points to the right side heating choices.

This is very illogical. Can you or anyone explain this contradictory evidence???

This became evident after replacing my intake manifold gaskets, P0171 and P0174 disappeared as hoped since it cleared my vacuum leak and lowered STFT and LTFT on both banks.

 

[2000StreetRod]

According to the Owner's Guide the air conditioning may operate in all modes except Panel (position between A/C & Off) and Floor. However, in the modes that the air condition can operate it will only come on when the outside air temperature is about 50 deg F or greater. As I recall, the PCM strategy contains a settable idle speed for A/C compressor off and A/C compressor on for transmission in Park/Neutral and Drive. When the A/C compressor cycles from on to off or vice versa the commanded idle speed will change. The temperature control knob is independent of the mode selected. When the sensed cabin temperature is less than the setting the vacuum operated heater water control valve will be open.

 

[MostlyNewExplorer]

Huh, bad lifter.... Could be. That will be a fun fix.

Sounds more like it was the lifters in 1, 2, 3 gone bad. Probably should check for proper oil flow on that side as well.