Empire

EDIT - Cliff Notes - Misfire issues
- engine stumbling a lot
- obvious misfire - did the "usual" stuff to try to fix it, new plugs, new coils, still missing
- according to the codes, it is a coil issue
- research indicates that it is a "multi-fire" spark issue. not getting secondary spark on one or more cylinders, as the misfire goes away at 2k rpms and above.
- currently, cleared the codes, waiting to see what comes back
- code of major concern - P0351 ignition coil A primary/secondary circuit malfunction. What does this mean in English?

----------------------------

I'm in over my head.
I need help from someone more knowledgeable about these trucks/this engine than just my general knowledge.


It is a 2003 F150 Supercrew. 4.6 liter engine.

It has a misfire from idle to 1,500 rpms.

Symptoms.
-At idle, it shudders. It isn't really a consistent miss, but it is there every couple of seconds. This happens both, in neutral, and in gear.
-revving in neutral, you can hear the misfire consistently until about 1,500 rpms, then smooths out.
-In gear, accelerating like normal, it misses enough to have a dramatic effect on power, until about 1,500 rpms, then it "lets go" and pulls like it should.
-From a stop, if you stand on the throttle, it will accelerate, but there is a noticeable difference in power once you hit the 1,500 rpm mark.
-I say 1,500, it isn't a hard cut right there, but between 1,500 and 2,000, it starts to behave. Once you hit 2 grand, the symptoms are gone.
-When cruising at speed, (45+) the transmission drops into overdrive, if you press the throttle just a little bit more, it will shudder very badly. Once it starts shuddering, you have to all but kick the throttle to get it to stop tripping over itself and shift out of overdrive. There is no light acceleration in overdrive.
-Going up a hill, the shudder is really bad, unless you hit the throttle enough to downshift and get the rpm's up.



So far,
- Cleaned the MAF sensor, got some crud off of it - no change in misfire
-I've replaced the spark plugs and coils thinking it was a bad coil. - no change.
-maybe I got bad coils - pulled them out, wrapped the boots up in electrical tape, one at a time, tested for spark, each one had a nice solid spark. reassembled. - no change.
- moved the coils around hoping to identify a bad one - no change.
I've not been able to discern it being a single cylinder causing the issue.
-replaced the IACV. the old one was going bad, it has been "humming" for a while now. got the new one in, got it adjusted and all that - it seems to run a bit better, but the misfire is still there.
- sprayed carb cleaner, starter fluid, electrical contact cleaner all over the engine bay trying to find a vacuum leak, couldn't find anything.


beyond soaking it in diesel and setting it on fire, I don't know what else to do to it.

blacksheep-1

Thorough job you're doing, did you happen to check compression while you were there?

Empire

I hadn't gotten to the point of thinking it was a compression issue.
no coolant in oil.
no oil in coolant.
no blow back in the coolant tank.
no noticeable smoking.
and when it pulls, it pulls like I think it should. Once it is above 2k, it just takes off.
BUT,
since I've ruled out so much already, compression test is back on the to do list.
I still have the old spark plugs that were in the truck before all this work started, I'll take a picture of then and post them up. Maybe someone with more experience than me at reading spark plugs will notice something I'm not. To me, comparing the plugs to pictures on-line, they look like either lean condition, or too hot of a plug, but I'm not certain either way.

What should the compression be?
Other than even across the board.

Empire

I'm thinking that I replaced a bad coil with a new, but bad coil.
I managed to find this while searching around -
most of that is over my head, but the important part here is
That seems to match up my symptoms pretty well.
Not getting the multi-strike in the lower rpms like I should be, but once it kicks over to single strike mode, (and the different fuel and timing map) at the 2k mark, it runs fine.
This is what most people are referring to as a "low grade misfire" on various forums, just no one ever really got to the whole multi strike at idle thing.

can anyone translate what these guys are talking about?
(original thread here - Ford F150 4.6L V8 troubleshooting)
and/or
can anyone help test each of these coils to figure out which ones are actually bad?
I don't know that I could afford to buy another set of 8, just to shot gun parts and money at this thing.
It would be really nice to be able to replace the one or two that are actually bad.


It is amazing to me that this kind of information isn't more readily available. I've been blown away at the straight up false information that is out there about these trucks. I know it exists with all cars, but you'd think with the millions of F150's out there, that things like diagnosing a misfire would be more knowledge and information based, instead of the "black magic" that is seems to be.
/rant

blacksheep-1

GOOD JOB!

Please post up what you find.
The truth is that the F150 series is about the most bulletproof truck there is, my last one had almost a quarter million miles on it and I actually teared up when I traded it in (on another F150 of course).

Empire

I had Advance pull the codes off the truck today.
Some of these were expected, others are a bit more confusing

P0351 - ignition coil A primary/secondary circuit
P1504 - Idle Air control circuit malfunction
P0171 - Bank 1 system too lean
P0303 - Cylinder 3 misfire
P0304 - Cylinder 4 Misfire
P0305 - Cylinder 5 misfire
P0308 - Cylinder 8 misfire
P0307 - Cylinder 7 misfire (pending)

I'm not sure what "pending" really means. So far, my searching indicates that the ecu "thinks" there is a misfire, but isn't 100% sure about it yet. So, we'll just assume that cylinder 7 is misfiring too.

My searching indicates that for the ECU to actually know there is a cylinder misfire, it is because the coil didn't fire properly. There really isn't any other way for the ECU to know a specific cylinder is missing otherwise. This tells me that it is likely that the new coils that are on there, are no good. Which is apparently a really common thing with these trucks.

I kinda figured the idle air control valve would throw a code since I had it unplugged with the engine running. But, the new control valve I have on there is making that same howling hum noise as the old one, if not even worse. So I wouldn't be surprised if this new one is bad too. BUT, this new one needs adjusted, and you can't really adjust it with all this misfiring going on. I was able to adjust the howl out of it, but then it wouldn't hold the idle. So, I'll work on getting this corrected once the misfire is under control.

The two codes that are really throwing me for a loop are the P0351 and the P1504.
P03051 - circuit A primary/secondary malfunction... It wouldn't surprise me that "A" = "1" heaven forbid that we keep the same numbers, But, if that is the case, then why wouldn't it just throw a P0301 - cylinder 1 misfire? What's the difference? I did some searching and I found everything from "replace all of the coils and plugs" to "replace the cam position sensor" and all points in between. Anyone really know what the P03051 code actually means?

As for the P1504 - bank 1 too lean code... which side is bank one? again, not been able to find a straight answer on this in my searching either. Personally, in my experience, this code indicates a catalytic converter issue. Which would be wonderful. FML. I would think if anything, there would have been a "too rich" condition because of all of the misfires. Unless of course the up stream o2 sensor is seeing the extra fuel from the misfires, leaning the mix out, and causing the whole thing to run lean. Which also makes sense. At least to me. I'm hoping that this is another one of those issues that can wait til the misfire is under control and hopefully isn't actually an issue.


As of right now, I had all of the codes cleared off. No codes back as of yet. It is still running crappy, stumbling all over itself. gonna try to put a few miles on it to try to make the codes come back and see what it says then.

blacksheep-1

It's been my experience (and others need to chime in here) that any "misfire" code is more broad than a simple "misfire" and can be caused by a multitude of reasons. I have a supercharged mustang that used to throw "misfire" codes when I had the timing (mechanically) jacked up and/or would pick up that code at altitude (smokey mountains) bumping the timing back a few degrees would stop it from re-occurring.


*****************Alert*********

I have the flu so I'm sort of out of it, but I just remembered something, go to the passenger side of the engine, track the vacuum/ whatever lines around the back of the engine UNDER the battery tray, remove the battery tray and see if they have a hole rubbed into them, look closely, it will be minor so look good, this will also explain the bank 1.
This was a common issue with this body style. Sorry I didn't think of it earlier.

Empire

if the truck wasn't completely stock, I would think it could be something like timing.
that does make sense though.

I will track down those vacuum lines you're talking about. I know which ones you're talking about. I sprayed starter fluid and whatnot in that area, hoping to find something, but didn't. at least, the fluid didn't expose anything. i'll get more through with it tomorrow.

novice question, what side is considered bank 1?
and how are the cylinders numbered?
I've not been able to track down a FSM for this truck yet, and I've gotten mixed answers searching the internet.

Update regarding the codes
Change engine light is back on.
still showing bank 1 running lean.
misfire on 3 and 4
and that "cylinder A circuit malfunction" one.

There was another one in there, that didn't make any sense, and the woman I had helping me ran through it so fast that I didn't catch it, and of course, didn't write them down, like the first person did.
I'll be hitting up the part's store again tomorrow to get the codes read again to make sure.

blacksheep-1

You're going to have to pull the battery tray and actually look at them, also bank 1 = pass side. (also side that #1 plug is on)
I'm sure that this is not part of the problem but if the mileage is over say..about 90k it's probably time for O2 sensors.

Empire

passenger side = bank one, bank one starts with cylinder 1 (I'm assuming at the front)
I'm also assuming that it is
1 2
3 4
5 6
7 8

Right?

I'll check out those vacuum lines.

I have no bout that it needs o2 sensors. Before all of this mess, I was looking at what needed done to restore, and maybe even improve the gas mileage. I was only getting like 13ish mpg. and the o2 sensors were on my list.
Hoping to get this thing running better, and get some catching up done with the maintenance. just gotta take one step at a time. sucks not having a budget to be able to just get it all done at once.