Unsolvable Explorer Rough Idle. Any OBD II experts? | Page 10 | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Unsolvable Explorer Rough Idle. Any OBD II experts?

MostlyNewExplorer- I hope my timing chain doesn't have that much slack with 58k.

At this point I believe it's probably the ECM.
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





Are you sure it ain't the tires?

I had a set of bad ones on an old Explorer and the the truck idled like a popcorn machine. Put some good ones on and Viola!, it ran good as new! I couldn't believe it!

Then again, I changed the injectors on it the same day. But I think that was just a coincidence though...



Tires.

:popcorn:
 






MostlyNewExplorer- I hope my timing chain doesn't have that much slack with 58k.

At this point I believe it's probably the ECM.

If you do some research you'll find they're prone to going bad with less miles on them. I've been driving mine for 7 years with slack in the rear chain. It has a sporadic idle also. The guides crack and pieces break off. Pulling the oil pan is the easiest way to tell if that's the problem, because you'll find pieces of the nylon guides in the pan.

If that's too much trouble, then good luck.
 






:crazy:
Are you sure it ain't the tires?

I had a set of bad ones on an old Explorer and the the truck idled like a popcorn machine. Put some good ones on and Viola!, it ran good as new! I couldn't believe it!

Then again, I changed the injectors on it the same day. But I think that was just a coincidence though...



Tires.

:popcorn:

I had a neighbor who said the same thing, but he was :drunk: and kind of :crazy:
 












Maybe he was, but he didn't have a 13 year old explorer with only 58k miles on it.

I'm thinking that the speedometer head has been swapped out on that thing at some point, and who knows how many miles the engine actually has on it?
 






I bought a truck thats 20 years old with 58k on it.

When vehicles sit for long periods, the fuel degrades and breaks down creating a varnish that will clog the injector's filters and nozzles.

Refurbished injectors are $110 off ebay and they come with new O-rings. He had the flipping intake off and they were right there!

But then again, maybe he should try putting a 3rd balancer on or drop the oil pan or check the voltage to his (inset random sensor here) or any other of the 8 pages of bullshit you talked this poor guy into, TO FIX A ROUGH IDLE!? :rolleyes:
 






The only thing I talked him into was pulling the oil pan.

You bought a truck that's 20 years old that had only 58k miles on it. What a coincidence.:rolleyes:
 












I'm back to it. The injectors are clean. I was hoping to see carbon buildup but they are spotless. I was going to have them cleaned, but rockauto had a closeout on the OEM Bosch replacements for less than having them cleaned so I'll be adding new injectors to the list. The resistance on the new ones are lower which is a good thing since the old ones were all just under the upper spec.

D669B677-2CEF-4279-8BA9-0059F9A2E683_zpssawhsuj5.jpg


Just a note for anyone that may replace explorer injectors. The injectors sit in a hard rubber "adapter". I have replaced injectors before and the oring went directly into the block. The adapter pulled out with every injector and was hard, brittle, and four cracked in half. I highly recommend anyone replacing the injectors go ahead and order a set of the adpters in advance so you don't end up stranded. Part number below.
E36EEB7C-C18A-4DBD-A208-4726B83E4C9D_zpsjg3zir7v.jpg
 






All of the new adapters and fuel injectors are installed. The injectors clicked right into place with little effort with everything being new. I'm glad Rockauto decided to put these injectors on closeout so I could rule out the issue. However the idle is still rough. My idea bank is exhausted and I am going to accept that this is an unsolved mystery. I did gain knowledge on fuel injection and modern sensors that I never learned as an old school V8 hobbyist. I appreciate everyone's help and suggestions along the way!
 






Just for humor here is the current list of items I have replaced.


New fuel cap

New Air Filter

New Motorcraft fuel filter

Sent to dealer and they could not find a problem and claims it has the latest software installed.

New spark plugs and wires

New IAC

New PCV

New MAF

New bank 1 and bank 2 downstream o2 sensor

New intake gaskets(I have changed these twice. No change either time)

New valve cover gaskets

Tested EGR valve with vacuum pump. Holds pressure and stalls when too much vacuum applied

Fuel pressure at 65 PSI

Swapped out fuel pressure damper on fuel rail with junk yard replacement(no change)

New crank position sensor

Swapped cam position sensor with Motorcraft branded one from junkyard (no change)

Swapped out coil pack with Motorcraft branded junkyard replacement (no change)

New Bosch fuel injectors (originals were spotless but wanted to rule out trash inside an injector)

Ran Marvel Mystery Oil with engine oil for about 200 miles (no change).

Tested Compression
 






I have a new set of questions relating to the ignition system. I am not overly familiar with the 4.0 SOHC ignition system, but from my reading it looks like spark is sent to two cylinders at the same time. Has anyone ever had the spark become weak on just one side? Does the coil pack contain just one ignition coil or does it have three(one for each leg)? Is there a way to test the switching signal from the ECM to make sure something isn't off here? I assume I do not have a separate ignition module since this is controlled by the ECM?

I ordered a spark tester (OTC 6589) that I hope will diagnose a weak or inconsistent spark. I swapped the coil with a junkyard Motorcraft coil and did not have a change so I do not think the coil is the issue.
 






Does your explorer have cruise control? Sometimes the linkage can get out of adjustment and make the idle wonky.
 






Yes it has cruise, but I believe that is electronic.
 






Well, nothing ever goes wrong with electronics.

Anyway, there has to be a mechanical connection to the throttle for the cruise control to operate, there is an adjustment there, and it can cause idle problems.
 






I had to replace a sensor that would not allow the cruise control to work about a year ago. I have disconnected the two mechanical cables with no change. The only other part I know of is the TPS sensor which seems to be operating properly by looking at its voltages.
 






Can you make a video of the vehicle idling, with the hood up looking into the engine so we can hear it?

I'm too lazy to go back and read the beginning of this post, so; is the engine rough only at idle or do you notice a miss anywhere else during acceleration?
 






It's only at idle and I don't think you will be able to hear it on a video but I can try
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.











Back
Top