Another P0306 misfire Vulcan engind problem

[ptf18]

Fellows. Got a Check Engine Light a couple weeks ago while highway driving on my way home (65mph or so). Stopped at a auto parts store to get it scanned and it was obvious the warmed up engine idle was rough when I pulled into the parking lot. (I figured something was misfiring). The auto parts store scanned it for me and the error code was P0306, #6 cylinder misfire.

Drove it home and noticed that during moderately hard acceleration and at highway speed driving I do NOT notice a misfire. Might be there but by the seat of my pants I don't notice/feel it.

At home the idle was rough as it had been at the auto store parking lot.

Pulled the #6 plug (Motorcraft SP 500 with 45K on them). Clean.... with a .044ish gap on them just as I had installed them. Reinstall it, disconnected the battery and left it that way till the next morning.

Started the truck up the next day. Started fine as usual but had a bit of roughness. READING thru some other posts, I see others have 3.0l that have a bit of idle roughness.

Drove the truck another couple hundred miles. The idle gets roughish after the engine is THOROUGHLY warmed up but again on moderately hard acceleration and/or a highway speeds I don't notice a misfire.

Got another CEL. Swapped the #5 and #6 plug wires ( their the original wires... I bought the truck new in 2002). Cleared the code and the truck performed the same as above.

Couple hundred miles later... another CEL. Came to the Forum and posts here led me to install a new Motorcraft coil pack. I found that the OEM unit was cracked in several places. Put the #5 and #6 wires back on their own plugs.

Again, cleared the code. Cold idle was still a bit rough but after another hundred miles or so ANOTHER CEL came on. All the while I could tell the warmed up engine idle was/is rougher than a cold idle.

Again swapped the #5 and #6 wires. (definition of insanity ?) Cleared the code and ran the truck another couple hundred miles. Again, cold idle a bit roughish but warmed up idle noticeably rougher . CEL came on again on my return home via the highway. Had another auto parts store scan the truck and they came up with...P0306....and no other codes.

So... I'm concluding that the #5 and #6 wires are OK as the problem didn't follow to #5 cylinder. .... I just received a NEW set of Motorcraft wires as I figure with 245k on the truck (and wires) what the heck...its just $$$$. AND that the OEM cracked coil wasn't the cause either.

This morning I started the truck and the cold idle was/is slightly roughish (as it always seems to have been). Didn't drive it and came here to post this.

SO... any ideas? I read thru the posts and see that others have had "similar" problems...some finding that it was bad valves....errrrrrr. Hope not. Others found bad fuel injectors.

I opened a propane bottle around various vacuum lines and connections while the engine was running (cold) ..... didn't notice any difference in idle.

My mileage hasn't changed noticeably. I have always logged all my fill ups (since I started driving 50 some years ago).

It seems to me my biggest CLUE to whatever my problem is how the cold engine idle roughness is ALOT less than the warm engine idle. What's cousing this????? No idea.

Thoughts?

2002 Ranger Edge Auto/2WD/ 3.0l Cyclone/ 245k miles/ Maintenance done religiously and some items more so. Motorcraft parts used (almost) exclusively.

Thanks all.....






Again swapped the

 

[RonD]

Welcome to TRS

When you have a misfire or rough running changing spark plug(s) is easy enough to try and not too expensive
But after that you need to do a compression test

Cold engine
Remove all 6 spark plugs first, need good crank speed for testing, so no compression on the other 5 cylinders
Test each cylinder and write down results
Get an average, i.e. add up the 4 "middle" readings and divide by 4, don't use highest or lowest
If a cylinder is 10% lower or higher than average then it may be a problem, yes higher too, lol

You can do a WET test after, add teaspoon of oil in spark plug hole, I use a straw dipped in oil bottle
Test one of the "average cylinders" first, write it down, it will go UP
Then test lower cylinders, if they do not come up to average or higher then usually burnt exhaust valve is the issue

Compression is mechanical, so black and white, no grey area like spark, fuel or air leaks, which is why its good to rule it out as "the problem" first or find out "it is the problem", so you don't waste time and money on "non-fixes" like spark and fuel

You can reverse spark plug wires 2 and 6 on the coil pack, these share one coil in the coil pack, fire at the same time, if misfire code changes to P0302 then replace coil pack
Most distributorless spark systems use Waste Spark, crank timing for spark
On a Ford V6 the coil pack is wired this way
[3 4]
[2 6]
[1 5]

These are the 3 coils in the coil pack

3/4 fire at the same time, as do 2/6 and 1/5

So any of these pairs can be reversed on the coil and it will not effect firing order, but if coil is cracked one spark may be reduced enough to cause misfire on that one connection
Reversing wires either moves the misfire to the other cylinder, meaning coil pack issue, or it doesn't meaning coil pack is OK

 

[ptf18]

RonD...Fellows...

I performed the compression test that RonD recommended (just the cold engine test) and the results were as follows:
#1......150psi
#2...... 153psi
#3.....152psi
#4......105psi
#5.... 127psi

AND....... #6...the cylinder getting P0306 codes ..... 80psi

I performed the test a couple times and the results were more or less the same.

RonD suggests repairing both heads which is the direction I'm going to go.

Couple questions. I bought the truck new in '02.... October 2002. It's the Edge model 2wd, Extended cab, Auto. Been a good truck. I use it "gently". Never offroad, towing or hauling heavy stuff. Currently get 20-21mpg. It's in real good condition and I take good care of it. 245,000 miles on it.

I've been researching this head "issue" that Ford apparently knew about for a long time, even issued a SB about it. BUT.... the SB only covers production years from 2003 (?) to 2008 (I think, last year this engine was used in the Ranger)

So , IF this low compression is due to the valve problem Ford knew about, why am I reading that pre-2003 Cyclone engines have the same issue?

Exactly what what is causing this problem? I read that the valves get "recessed" into something due to poor quality head material.

I've seen some pictures on the 'net that shows 1) the EXHAUST valve head appears to "deform" BUT the contact sealing surfaces seem OK. 2) that there are NO "insert" style valve seats in the head RATHER the seats are cut directly into the head material 3) these heads are "poorly" designed and subject to cracking.

As for replacement parts..... Starting with the heads. I read that there are NEW non-Ford produced heads (china I suspect) that are of "better" design.

Thoughts about these? For 98% of the parts I've ever changed on this Ranger I've ALWAYS used Motorcraft so I'm leery of using others.

OR should I get my heads "rebuilt" (if they are rebuild-able) and if so any recommendations by who?

The Ford SB lists needed parts. Is this list complete, at least for the 100% items (gaskets, seals, hardware) OR are there other 100% items I'll need?

Any suggestion on other parts I should replace? I'm thinking fuel injectors (new , rebuilt OR exchange ?)

Some You Tube videos show that the radiator and various front engine components need to be removed (P.S. pump, A/C compressor, etc) is this correct? I really prefer not to pull things I don't have to but on the other hand I don't want stuff in my way. Does the hood have to be removed?

Thanks all..... more late I'm certain

 

[2011Supercab]

Injectors are not going to help your compression issue.

Before pulling the heads, you need to do the wet compression test to see if it's rings or valves.

No sense putting new/rebuilt heads on if the rings are the problem.

 

[ptf18]

Fellows.... Just poured about teaspoon of oil into the "bad" #6 cylinder.

Did a COLD compression check on that cylinder.....

Got 180psi..... had 80psi dry....

Oh boy....

Suggestions???? Should I bother doing a wet compression check on the other cylinders?

Was dreaming about pulling heads when I went to bed last night........now an engine????

 

[RonD]

Yes, that wet test would certainly point to worn out rings or cylinder damage

 

[ptf18]

Fellows... Just finish with the "wet" compression check.
WET DRY
#1......218psi 150psi
#2..... 208psi 153psi
#3.... 230psi 152psi

#4....185psi 105psi
#5....230psi 127psi

#6....185psi 80psi

I'm going to reinstall the plugs, run it and do the lighter/dollar test at the exhaust.......

Awaiting your suggestions....

 

[RonD]

If its was rings/cylinders then all would have come up to 200+
So it is most likely only valve issues, and exhaust valves are the most common to leak on ALL piston engines

So, in my opinion, I think you are safe to just do the heads
Have a look at the cylinder walls once the heads are off, ring issues are just not that common any more with the newer materials being used
If you had 400,000+ miles on the engine then maybe a rebuild would be in order

 

[ptf18]

Fellows. Got everything back together. Engine started right up...as always. Took the Ranger out for a spin and...it ran as it always has....just fine. No CEL...yet. Still can feel a slight miss so I suspect I'll get a CEL soon.

Installed my vacuum gauge on the engine and drove the truck with it in place (taped to the windshield). At idle I have 17"ish hg of rock steady vacuum (245k on the engine). I did a "snap test" with the throttle (quick rev up). Vacuum drops to 5"ish hg, climbs up to 22ish hg then settle backs to 17ish" hg.

At a 55mph cruise on a level highway I'm getting 17,18,19"ish rock steady vacuum.

Don't know what long term I'm going to do. If I was a "regular" owner I'd just keep my eyes covered and drive the darn thing.....

I don't have a issue spending big bucks on fixing this truck but I'd like to know exactly what is causing the misfire. Hate to pull the heads only to find damaged cylinders of some sort and then have to make whatever arangements to get the entire engine up and running. On the other hand, without pulling the heads I won't know if its the heads OR cylinders. Maybe I'd get lucky and find out it was head gasket (doubtful).

Thanks for the input.. I'll keep you posted. Post me if you have any other thoughts

I

 

[ptf18]

Fellows. Drove the Ranger on a 120 mile or so round trip this morning. Truck ran fine although I still feel a slight miss while going out on the trip. Got the CEL when I got to my appointment and noticed that the miss was definitely more pronounced on my return journey while I was idling at stop lights.

Got home with a thoroughly warmed up engine and just for grins tried the 'lighter" test at the tailpipe...... GEE...

Lighter flame was easily sucked into the tailpipe before being extinguished. I repeatedly performed this test and repeatedly got the same results. I attempted to take a picture of the flame getting sucked into the pipe but it happens so fast I can't catch it.

Funny thing is that I performed this test the other day and the flame was NOT sucked into the pipe...BUT....the engine was not THOROUGHLY warmed up.

Based on these results it "appears" that an exhaust valve is an issue....... just as RonD suspects. On the way home I stopped at an auto parts place and had them check for codes....Same-Same....P0306....#6 cylinder misfire.......

I'M stumped..... I wish there was a big sign that said "I'm the problem".....

On the other hand maybe..... I've got 2 PROBLEMS... a bad exhaust valve AND damaged rings...... Um?????

Thoughts?

 

[RonD]

I don't think the rings are bad, just the valves

Pull out oil dip stick
Start engine
Put finger over dipstick tube opening, see if you feel a bit of suction OR out flow
Put a piece of paper near dipstick tube opening, see what it does, sucks in or blows out, or fairly neutral, just sits there
REV engine as well when testing this

When you have bad rings you have "major" Blow-by, which causes major outflow at dipstick tube, should actually push the dip stick up if it was seated, lol


Blow-by
Every time a cylinder fires some of the exploding gases will "blow-by" the piston and rings, even on a brand new engine
This is why all engines have a PCV(positive crankcase ventilation) Valve system

In the old days there was a tube on the lower block or upper oil pan that was pointed down at the ground
Blow-by was just vented out of the crankcase along with Oil Vapor it causes
Blow-by IS exhaust gases
So Emission Laws required that venting to be stopped
PCV system uses engine intake manifold vacuum to suck Blow-by gases out of the crankcase to be burned in the engine

Only place in an engine that gets HOT enough to Vaporize Oil is cylinder walls and sides of pistons when the Blow-by "blows by", lol
These areas are coated with oil to lube and cool the engine, some of that oil is vaporized by the blow-by
If rings were bad you would also have ALOT of oil vapor coming out of dip stick tube and PCV Valve and Breather hose would also have am extreme coating of oil, not a little, which is normal, ALOT

 

[ptf18]

Fellows...RonD. Haven't accomplished RonD's blow by test yet. Being "retired" I don't get out much so I haven't a "need" to drive the truck.

Would like some input on Heads. What caused this "valve recession" issues?? What exactly happens? And how does it cause valve leakage?

What do you all think of these "new" produced heads? I take it they are NOT Ford produced, probably china? Reason I ask is that if the Ford OEM heads are problematic why would be installing a set of OEM Ford "rebuilt" heads be a good idea? OR should I be looking at Ford OEM "rebuilt" heads that were NOT produced in the years that the Ford S.B. covers. What about using the 8mm valve (stem dia) heads (pre-1999???) rather than the 7mm valve (stem dia) heads.

 

[RonD]

2002 Ranger 3.0l probably doesn't have Valve seat recession issue, that was 2004 to 2006 3.0l Ranger model years
But it was caused by poor machining of the heads and/or poor exhaust valve seats, and not 100% failure just a known issue on some of the 3.0l heads in those years, so engine assembly plant issue

Any piston valve gasoline engine can get burnt(leaking) exhaust valves, its just one of the more common failures
That why most have heard the term "Valve Job", common repair for piston/valve engines

Intake valves are cooled by the incoming air/fuel so run cooler
Exhaust valves get HOT and stay HOT, so this is where the problem usually occurs

Valves rotate each time they are opened, their seats are cooled by coolant circulating in the head
When a valve is closed(which is most of the time) heat is transferred from valves edge to the seat

When a cylinder fires temp can get as hot as 4,000degF, but 1,500degF is usual EXIT temperature, that's what the Exhaust valve and its seat has to deal with, this exhaust gas exits between valve and its seat into the exhaust manifold so BOTH get and stay VERY HOT

If valve doesn't rotate a few times it can get a REALLY HOT spot which can cause a leak to start even if it starts to rotate again its a weak spot
Any slight leak point is a place were that 4,000degF Explosion can escape, and that makes a bigger leak, and bigger and so on

Pinging/knocking, this eats away at valves and seats

Lean condition, cylinder runs even hotter

Exhaust valve can WARP a bit when HOT, starts to leak

There are a few more reasons but the main reason is that you have Valves, so will have valve issues at some point