Hard Starting on 03 4.0L

[Hitchhikingmike]

I currently have 65k miles on my explorer, this reaffirms my previous conclusion to just go ahead and replace the fuel pump, W/P, radiator, alternator and hoses at 100k miles regardless, just for reliability- on my own time myself.

I plan on running my explorer to the ground, so I will do all the above for reliability and connivence at the same time.

It seems that most fuel pumps goes out shortly after 100k miles.

 

[Hitchhikingmike]

Also, advice for your rear end-

Since its whining and the bearings are a bit rough, that means that you have mettle particles in the oil, escalating your bearing wear even more. You should change that oil. But this won't stop the howling the damage has already been done, it will just decrease the rate of future wear. And since your bearings are already in the habit of shredding themselves into bits in the oil, it is not unreasonable to just change out the rear oil every 10k miles for now on, to keep all future wear to the most minimal.

My rear end dose not howl, and is perfect condition, and I change my rear oil every 20k miles.

 

[thepotroast]

Also, advice for your rear end-

Since its whining and the bearings are a bit rough, that means that you have mettle particles in the oil, escalating your bearing wear even more. You should change that oil. But this won't stop the howling the damage has already been done, it will just decrease the rate of future wear. And since your bearings are already in the habit of shredding themselves into bits in the oil, it is not unreasonable to just change out the rear oil every 10k miles for now on, to keep all future wear to the most minimal.

My rear end dose not howl, and is perfect condition, and I change my rear oil every 20k miles.

I did change the rear oil about 10k miles ago with Mobil 1 Synthetic 75w-140 and an additional 4oz of friction modifier, back when I started to notice the whine...it hasn't helped. As many have reported on here, the whine is coming from the gears because Ford used a vendor for the gears in the 3rd Gen X's that was creating the gears on "worn" equipment, and the gears do not retain their integrity. Because of this, it is quite common for 3rd gen's to have a howl coming from the rear diff, so much so...that there is a Ford TSB for this very issue, which is what my differential clutch pack was replaced under (for free) at 65k miles...because Ford knows it's a problem.

The downside to this, is they replace it with gears from the same "new old stock" gears that were made when the original gears were made, and these gears end up with a life of about 60k miles as well, before the howling begins. Ford also only puts a 75w-90 lube in the rear, and it's instead recommended by most to put a 75w-140 in the rear instead, and to add additional friction modifier for the clutch pack...which I did.

So you are lucky you don't have the whine yet, but you also only have 85k...it's a very common issue on the 3rd Gen's

 

[thepotroast]

I am also updating the status of my situation. Brought the truck home yesterday with no problems, went out to start it this morning....had the same no starting issue.

So I took a second to get the red out of my face, and called the dealership to let them know that the job did not fix the issue. They offered to send a tow truck out to pick it up, and bring it in right away. Got a call from them a couple of hours later, and the technician told me that as soon as they dropped it off, he went right out and it cranked right up. So I told him that I cranked it over a dozen times this morning, with no start...he told me they would run another diagnostic on it. He called back, and told me that it threw a intermittent code for the coolant temp sensor...a code that it didn't throw yesterday. No CEL came on however.

He said that the ECU compares 4 sensors when you start the vehicle (MAF, coolant temp, oil, and a fuel sensor), and then adjusts the amount of fuel/air to deliver accordingly. He told me that the code it was throwing was making the injectors push too little fuel (lean) into the motor, because it thought the coolant was up to temp, when it fact it's a cold motor. This would make sense why once it's warmed up it's starts fine, because a warm motor doesn't need a richer mixture to start...so the injector's lean it out.

He said they would throw a new coolant temp sensor in, and that should fix the issue. He assured me however that I definitely had a 0PSI fuel pressure at the initial crank, and that they bench tested the fuel pump after pulling it (at my request) to assure it was bad, and it was...so it's not a huge deal.

I actually had the coolant temp sensor replaced a year ago when I had the entire cooling system redone, however it was not done with Ford parts, just at a Joe's Garage down the road...(a reason I didn't take them this job...), and I'm sure the sensor just took a crap.

So I will go pick it back up again tomorrow, they said it's ready and runs fine on a cold crank, but I requested them to not start it tomorrow before I pick it up, and for me to have the honors...

Will update...