2003 Sport Trac Conundrum

Hi Guys!
I need to describe this Scrabble game that has me by the short hairs. I ask your indulgence while I lay this out as best I can. It's long and I have spend a bit of time looking through the forums/threads for any ideas. I've found pieces-parts. But nothing that hit the nail. So...

2003 Sport Trac 4x4 XLT 4.0L V6. Guilty of over-mileage oil changes. 247K miles.

About 4 months ago my starter began acting up. The hammer trick would only work for a short time and physically, I have trouble doing it. A friend's daughter dates/works with a guy that volunteered to change the starter for nothing. I supplied the starter. He had a rack, so I let him at it. Watched him work. He became more and more frustrated as he couldn't get the starter out. When I saw the cutting torch, I got a little nervous. There is a part that I can only describe as an "torque restrictor" mounted near the transfer case. Described as not needed, it was cut off the frame. (I still have it).

So he put it all back together with the new starter and we went off down the road. (You might be asking, "What does the bracket have to do with anything?" Keep reading)

About two weeks later, girlfriend was rolling down I-12 and, as described by her, started running rough and soon just killed. I went to meet the skid truck and had it towed to my house. I couldn't get it to start. So, after a deep breath, and I tried again to start it. It took a second and some serious pedal pumping. But it started. Idling was rough. But as I gave it a bit more gas, it smoothed out a TINY bit, to where I could pull it in the carport to work on it. I bought a new coil pack, and set of plugs and wires. My first thoughts were timing chain. But with starting, I thought that I'd begin with ignition. I put the battery on the charger, to be safe.

These engines are not easy to change the spark plugs. I started replacing the plugs first. Every one of the six plugs came out with the center electrode looking like piranha teeth - short and pointed. No oil on them. So I set gap at .54 and put new ones in.


Then the coil pack and finally the wires. I noticed that the battery was losing voltage. Cleaned the posts and it seemed to calm down. It is jacked un and on stands now so I can slide under with the creeper and check the wiring to make sure that during the excision of my frame parts that a wire wasn't burned. *To note - When I looked the truck over the next morning after the tow, there was a wire and electrical plug hanging down from the transmission area. Plus I have no clue as to whether or not this guy cut or burned a wire underneath. Could/would a dead short cause any of this? (I should get credit for one stupid question)



Before I get too far, I could not get it to throw a code.

After dumb mistakes concerning the cylinder banks and plug wire identification, I put the key in and started it. No change at all. Will run. With protests and still what feels like a dead miss. Starts and runs with help. Meaning if I let it go to idle, it kills. Shift into reverse, kills. Still won't throw a code.
I figured that if it was the timing chain, a LKQ/Used engine would work. To get a Jasper or other reman runs close to $5k. I found one for $1495 with 81K miles, 5 year warranty and free shipping to repair shop.

So here I stand. I don't know where to go at this point. No way can I do the timing chain(s) thing. Too old and too broken - Me, not the ST. Lol. Shops laugh at doing timing chain job. (I actually don't blame them) I'm looking for some learned opinions. I do have another coil pack and I was going to swap that. But after a crank sensor busted my butt, I had no idea where to start with this. I really do love my truck. But that damn line between wallet and physical pain...

Thank you in advance for reading.

Jes S.

Update - Changed coil pack and confirmed that plug wires were from pack to cylinders/plugs correctly. Found "mystery" connector source - appears to be transmission to tach/speedometer connection. Nothing new with start/run thing. Still starts with dead miss.
Thanks to those who read the post. I think I'll have to save up a bit and get it to a professional. It may cost a few bucks. But at least I can get a solid diagnosis that will give me some direction as to what is going on.

Are these trucks hard to work on? The 4.0 engine specially?

Fuel injectors?

@gfgjester, sorry to read of the hassles ur ST is dishing out. Although I don’t have much intel as to all the problems it could be, that large metal round weight that ur buddy cut off in order to get to the starter (it bolts to the frame), I believe, is some kind of vibration dampener. Anyway, I had to use everything from wrenches, an impact, and wobble extensions (and a fair amount of smashed knuckles and cuss words) to get it off so I could access the starter on my 2002 ST. I never put it back on (I actually pitched it), and I’ve not noticed anything different in drivability.

Anyway, an engine (or any given cylinder) needs only four things to fire: 1) fuel, 2) spark, 3) compression, and, 4) all these basically at the same time - maybe consider compression next? Changing plugs is a b**** to do, and affixing a compression tester will likely be just as big a pain, but at least that would take something else off the table. Since u went through the plugs/wires/coil pac, it’s unlikely #2. The fact the other cylinders are getting fuel, it’s unlikely #1, and since the other cylinders are operable to some extent anyway, I doubt it’s #4 cause when a timing chain goes, so do the valves when they go out of synch and the pistons start smacking them - and it won’t start.

FYI, I’m not a mechanic by trade or education, this are just the things that I picked up from my old man growin up when I was the one chasing his tools and washing parts in an old bucket with gasoline. Lol. Best of luck, my friend. Keep us posted.

rwbenner said:

@gfgjester, sorry to read of the hassles ur ST is dishing out. Although I don’t have much intel as to all the problems it could be, that large metal round weight that ur buddy cut off in order to get to the starter (it bolts to the frame), I believe, is some kind of vibration dampener. Anyway, I had to use everything from wrenches, an impact, and wobble extensions (and a fair amount of smashed knuckles and cuss words) to get it off so I could access the starter on my 2002 ST. I never put it back on (I actually pitched it), and I’ve not noticed anything different in drivability.

Anyway, an engine (or any given cylinder) needs only four things to fire: 1) fuel, 2) spark, 3) compression, and, 4) all these basically at the same time - maybe consider compression next? Changing plugs is a b**** to do, and affixing a compression tester will likely be just as big a pain, but at least that would take something else off the table. Since u went through the plugs/wires/coil pac, it’s unlikely #2. The fact the other cylinders are getting fuel, it’s unlikely #1, and since the other cylinders are operable to some extent anyway, I doubt it’s #4 cause when a timing chain goes, so do the valves when they go out of synch and the pistons start smacking them - and it won’t start.

FYI, I’m not a mechanic by trade or education, this are just the things that I picked up from my old man growin up when I was the one chasing his tools and washing parts in an old bucket with gasoline. Lol. Best of luck, my friend. Keep us posted.

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Small update. Just realized I had a gap in my knowledge (not uncommon for me by the way lol). I always thought these had some form of throttle body injection….I was wrong. I guess each cylinder does have its own injector. So to revise my previous, if u can isolate the dead cylinder by pulling/replacing one plug wire at a time, then u could try swapping its injector with a nearby cylinder and see if the miss follows it. This would support the problem being with #1 as discussed above.

rwbenner said:

Small update. Just realized I had a gap in my knowledge (not uncommon for me by the way lol). I always thought these had some form of throttle body injection….I was wrong. I guess each cylinder does have its own injector. So to revise my previous, if u can isolate the dead cylinder by pulling/replacing one plug wire at a time, then u could try swapping its injector with a nearby cylinder and see if the miss follows it. This would support the problem being with #1 as discussed above.

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I was talking to my brother yesterday and he asked me if I had checked the injectors. I said, "What injectors?" I was under the (i guess) impression that the SOHC 4.0L did not have injectors. Now I'm off on another quest. LOL. Thanks for the nudge. I just started it and moved it from the carport to the drive. Figures!

Well, thanks so much for the lead!

Roy Trolinger said:

Fuel injectors?

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That's what we're thinking. Research time for me. Thanks!

rdcarpenter82 said:

Are these trucks hard to work on? The 4.0 engine specially?

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For me personally, the things that are normally easy to do, like changing plugs on a Chevy 327, are put in to where I have asked my self if Ford didn't want owners working on the vehicles. Now, I'm still undecided. Thinking that vehicles have just gotten more difficult because of newer technology. Just an idea,

Thanks!

gfgjester said:

For me personally, the things that are normally easy to do, like changing plugs on a Chevy 327, are put in to where I have asked my self if Ford didn't want owners working on the vehicles. Now, I'm still undecided. Thinking that vehicles have just gotten more difficult because of newer technology. Just an idea,

Thanks!

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Yea I have a old wrangler tj. I was thinking about getting one of these but I’m afraid I won’t be able to work on it like I’m use to with the old jeep.

I'd look really close at the overall access to the Sport Trac, including engine compartment and cabin. Make the same comparison withe the Jeep. Mine has a great interior. I have "fold down rear seats" lol it's the old personal preference. (Sly grin...) But you can't make a good decision without the truck. Go ahead and nab it. Yeah, That's the ticket! So all the time you spend working/playing and noting data with it won't be wasted time. (Ha-Ha!)

Lol that’s scary. I don’t know.

Small update - I got a full set of injectors and plan to change them. The operative word is "plan"! LOL! If it isn't that, I will reevaluate. Thanks for the tips!

Just a note - Changing a/all of the injectors on this engine is a major job. R&I of the intake manifold is not any quick and easy thing. Ford was even kind enough to use Torx head bolts for the manifold. Thank goodness I have a carport where I can follow my own pace. I love my ST. But it is extremely hard to suppress the urge to find the first FMC engineer I can and introduce him to the knee-nut formula.

So now, in the continuing attempt to replace the injectors on my 4.0L V6, I got enough pieces-parts off to see the injectors and the mounting bolts for the manifold. Snapped the Torx socket on an extension and dropped it in the hole. NOT to my surprise, the shank of the socket will not fit through the manifold access hole. Does anyone have any idea how I might remedy this situation? I can't get to the bolt itself, so I can't figure out the size. This is quickly becoming a pain on the crankshaft sensor level... I'm open to any ideas. YouTube has lots of vids on 4.0L V6 engines in Explorers. NOT Sport Tracs. Only thing that comes to my mind is a monkey f***ing a football! Thanks in advance...

Thanks for all the advice an info, guys. It looks like I'm going to be an ex Sport Trac owner. I figured o bypass and the BS and just buy a LKQ/Used engine. The cheapest I could find was around $1295. Shipping would have to be figured. Then the labor to do the swap. $1500-1800. That's close to four grand. Gotta pick mortgage payments or engine. I have another vehicle. It's just not my "Baby". But life goes on and either you pick up, dust off and start walking the trail, or give up and be miserable. I'm walking... Cheers, y'all!

Hi, my friends. Die hard Sport Trac owner that I am, I threatened to sell my ST. Been looking at it and researching. Trying everything to salvage my "child". In talking to a few mechanics, I told them that I could start the engine and move the truck around the yard and drive. This seems to have made a big difference in potential repairs. This is what I was told - If it's running, then chances are that the chains and sprockets are ok and the guides need replacing. So I made the decision to obtain the funds and send it to the shop. Would cost much, much less than an engine, ($900-1900). So the Phoenix could rise from the ashes! We'll see! I'll post as I learn.

Good stuff! Hang in there!

gfgjester said:

These engines are not easy to change the spark plugs. I started replacing the plugs first. Every one of the six plugs came out with the center electrode looking like piranha teeth - short and pointed. No oil on them. So I set gap at .54 and put new ones in.

View attachment 4433

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Nice work!
Your center electrode wear appears normal. Like the OEM Motorcraft SP-500 plugs, the NGK TR55GP are a "finewire" design with very small center electrodes,

https://www.google.com/search?sca_e...2ahUKEwjf-Oum0NGGAxVMIUQIHWlgEVQQtKgLegQIDhAB

2005 XLS

What was the outcome to this problem?

Incidentally, iridium spark plugs look like that.
Nothing wrong with your spark plug.

FWIW:
Like was said above, the problem could be either spark, fuel or mechanical.

First thing I would'a done is check the spark.
The way I do that is to get a ground wire and attach it to the frame (make sure the frame grounds to the battery!).
Then, with the engine off, loosen all the wires on the distributor cap.
Then start the engine and remove one wire and simultaneously replace it with the ground.
You don't want that powerful spark jumping around inside the distributor cap or it'll ruin it.
Do that for all 6 cylinders.
If the engine idle and running harmonic doesn't change, then you have a problem with that cylinder.
If it does, then you probably don't.

From this point forward, if you find a bad cylinder, you can check each piece of the process in detail:
Electrical, fuel and mechanical.

Here's a good video for checking the wires and plugs, if you have a lab scope.

You need to do a cylinder compression test and leak-down test to check the mechanical.

You need to do a fuel injector test, so if you have a scanner that can do an injector shut-off test (while it's running), you can test the fuel injectors.
Or if you can reach the injector connectors, you can unplug them one at a time to see if that causes a change in how it runs (= probably good).

That's how I would've approached this problem to narrow down the possibilities.
With these new computer vehicles, it's essential to eliminate the known and then work your way to the unknown using PROCESS OF ELIMINATION.

Also, these Sport Tracs are notorious for timing chain cassettes.
If your cassette goes bad and your timing chain hops teeth, you're gonna bend valves, and that's it for the engine (unless it's rebuildable).
If the cassettes are bad and the chain doesn't skip teeth, it'll run bad b/c of the slop in the chains.

Anyway, that's some stuff to look at for someone else who may need a place to start to check a runnability issue.