Bad COP? | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Bad COP?

JakePSD

Well-Known Member
Joined
March 25, 2010
Messages
402
Reaction score
1
City, State
Ohio
Year, Model & Trim Level
2003 Mercury Mountaineer
I'll give you guys my symptoms and we'll see if you all think I'm right. For a few months now my 2003 4.6L Mountaineer has been having a hesitation at certain RPM and throttle input. It first started a few months ago, shortly after I got it back on the road after an engine swap. I know little about the history of the truck prior. I bought it cheap because the engine was tied up. Anything over about half throttle it would hesitate real bad and just had no power. I attributed it to old gas since it'd been sitting for well over a year. I filled it up from empty with premium fuel and dumped a container of injector cleaner in it and took it out for a good ol' Italian tune up. It seemed to get better but never fully went away. No SES at this time. I just decided to drive it until it got worse so I could actually pinpoint the problem. Since then I have changed the fuel filter also.

Since then it would intermittently run rough for a minute or so on a cold start, along with still having some hesitation at mid throttle. WOT usually will hesitate for a second or so, then smooth out and run fine. Some days though it runs perfectly fine with no miss or hesitation.

Fast forward to last week. Finally got an SES, P0152. Reset it and went about my day. This morning I was able to learn a bit more about it. I had no SES on last night when I parked it. This morning when I started it, it idled rough for a minute or 2, then smoothed out. Put it in gear and started driving and within seconds the SES came on.

This is where you guys come in. My thinking is that I have a weak coil(s) on bank 2 causing an incomplete burn and loading the manifold up with partially burnt fumes, then when I start driving, the added exhaust flow forces all of that past the the O2 sensor showing a rich condition. Once I clear the SES it stays off for the remainder of the drive. Am I on to something? Or am I dumb and it's something else?

What is a good way to test coils? I'd rather not spend a bunch of money on new coils if it's only one or 2. Plus I have a parts truck I can yank coils out of to replace the bad one(s). Fuel pressure has also ran across my mind a few times. Is there any special fitting to temporarily hook a fuel pressure gauge to the schrader valve on the fuel rail? Is there any reason while doing this I couldn't use an oil pressure gauge since that's what I have laying in the shop? I mean it just shows pressure right? The only difference would be that one says "oil" and the other says "fuel" right?
 



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!
.





pull the drivers side rear coil and look for moisture, i had a puddle in mine and would do just about what you described though mine idled rough after a while through a rich code not the same as yours....when i pulled the plug it was rusted and may have stopped firing altogether, but i think it would fire on and off before it completely quit...
P0152 is the OBD-II generic code indicating that the O2 sensor for bank 2 sensor 1 fails to have a lower voltage output below 1.2 volts for more than 10 seconds indicating a lack of oxygen in the exhaust stream or a short to power in the sensor circuit.
hope this helps
 






It does help if for nothing more than an idea, which I am open to any. I'm fairly sure that's not my problem but I will for sure look. I just replaced the plugs when I did the engine swap. Did all new gaskets (besides heads) on the engine while it was out. I'll inspect the wires to the O2 sensor for damage as well.
 






From my experience, there isn't a good way to test the coils. When I had a misfire, I tried moving coils around, but it didn't help (the misfire didn't move with the coil). See this thread:
http://www.explorerforum.com/forums/index.php?threads/2002-explorer-4-6l-misfire-cylinder-4.455298/

Finally I gave up and bought a cheap set of coils off Amazon thinking it was worth a try for $35. They worked, misfire gone (although it has only been 3-4 weeks since I changed them). I ordered them from "U.S. Based seller" http://a.co/b3pVBZP
 






Mine isn't even showing a code to point to a specific cylinder. On the 7.3 power stroke you can hook a scanner up and look at what they call a "PERDEL," which stands for percent of deceleration of the crank. You can monitor that and pinpoint a weak cylinder by seeing which one has the higher percentage of crankshaft deceleration. I have a good scanner, Auto Engineuity on my laptop, that can read that on my diesel. Do the PCM's on these trucks support that function?
 






Well today I swapped the coils from one side to the other to see if the rich code followed. No luck. I also cleared the computer and capacitors using the jumper wire from the positive and negative cables. Still got the same code. I'm gonna order those same coils linked above and see if that helps. I'm also gonna check the fuel pressure somehow.
 






What fitting do I need to temporarily hook a fuel pressure gauge to the schrader valve on the fuel rail? Is there any reason while doing this I couldn't use an oil pressure gauge since that's what I have laying in the shop? I mean it just shows pressure right? The only difference would be that one says "oil" and the other says "fuel" right?
 






Might be good if you use some type of glycerin filled gauge on the fuel side. It would help dampen pulsation, if any present, and give you a steady reading.

As for the Schrader adapter you would only need something to convert, from I would guess, male side of schrader valve output to female NPT side of your gauge.

Use teflon tape so there are no leaks and fire hazards.

Gauge would need to be no more than 100 PSI.
 












Coils rarely fail. I have ran several Ford COP equipped motors over 200K and never had to replace a COP. I do always replace the boot and spring on them with each spark plug change. When I remove the old boot and spring, I use paper type fingernail files cut in half length wise and file the copper contact in the coil's nipple. Works like a charm. I have done this on a 04 Focus 2.3, 01 Excursion 6.8, 01 F250 5.4 and now my 07 F150 5.4.
 






The springs were kinda crappy looking on most of em. Looked rusty. For the cost of new boots and springs I might as well just replace the coils too really.
 












I would have thought it'd be better to take out the inside of the schrader valve and use a male fitting?

Leave the valve core in. system remains pressurized for a little while. Less chance of fuel spill and a fire you really don't want.

Trust me!
 






UPDATE! This will make you say "WTF?" My truck is for sure a female that is about to start menstruating based on the moodiness its been having. So saturday I had to use it to pick up a pair of jet skis I bought. About an hour drive one way. On the way there it starts its misfiring crap again. Cruise set it was fine, but adding some throttle made it start missing. The drive home however was horrible. As soon as I hit the interstate it started running like total crap with the extra load on it. I had to lock it out of O/D just to make it run alright. SES light came on quite quickly. After I got home and unhooked the trailer I had to make a quick drive a couple blocks to grab stuff from the drive thru and thankfully it was only about a 3 block drive. As soon as I left my driveway it was missing worse than ever. Like completely dead cylinders. And the SES light started flashing at me, which as I understand means that its running so bad that it will cause quick damage to catalytic converters. Scanned it when I got home and had codes for cylinder 1 misfire, cylinder 8 misfire, and multiple cylinder misfire. Parked it for the night and worked on it all afternoon sunday.

This is where the "WTF" comes in. Since I have a parts truck with a 4.6 in it, I swapped out #1 and #8 coils. #8 misfire went away, but #1 remained. Swapped #1 with #2, still had a miss on #1. Tried 4 other coils in #1, and still had the miss. Pulled the #1 spark plug and it looked fine. Fearing of a mechanical issue such as a cracked ring or valve, I ran a compression test. All cylinders tested good so I put it back together. When I put everything back in I purposefully mixed up the plugs and coils so they didn't go back into the same spots or anything. Started it up and it ran perfect, and has been since. WTF?

I think it's safe to say it's ignition related, and my new coils will be here in a couple days. I filled up the fuel yesterday and averaged 9.xx MPG on that tank...
 






Check for water in the plug well. I had the same problem. Took the coils of to test them, wells were full of water...
 






They were dry other than the residual water left over from hosing down the engine bay the day before. I've replaced about every external gasket on the block so leakage isn't really an issue.
 






Figured I'd post an update. I went ahead and replaced the coils when they came in, and it has been running fine ever since. We'll see when it starts getting colder if it still has a rough idle when starting it.
 






Back
Top