Hello everyone. I just bought this lovely truck that came preloaded with codes P305 (cylinder 5), P316, and P430. Runs fine except when idling.

Also, I am aware of TSB 05-26-3 and already began troubleshooting:

1. I installed all new spark plugs.
2. I installed a new Motorcraft coil pack and new wires (Denso).
3. Compression test:
Cylinder 1: 180 psi
Cylinder 2: 150 psi
Cylinder 3: 150 psi
Cylinder 4: 150 psi
Cylinder 5: 150 psi
Cylinder 6: 170 psi

There is also what looks to me like a pretty big crack on the driver's side exhaust manifold, same side as Cylinder 5. I read that cracks in the exhaust manifold can usually be heard as a rattling type sound when the exhaust gas is escaping, but that it goes away as the engine warms up and the metal expands. In my case, I am hearing a mechanical (almost plastic) clicking sound that increases and decreases with RPMs but it's definitely not going away. Strangely, I can hear it well from the tail pipe and not so much from the engine compartment. I used the stethoscope on the cylinder head and couldn't hear anything and nothing sounded broken.

 

Update: Replaced fuel filter today and no change. I have a fuel injector on order that I'll install next week. I removed intake manifold today and cylinder 5 intake walls were burned and much blacker than the others. Put my finger down in the hole and it had a light coating of oil. Not sure if that's normal or not.

 

Welcome to the forum

Did you do the compression test with COLD engine, all spark plugs removed, and held gas pedal to the floor when cranking engine over?
And I would have done a WET test(add oil) after doing the DRY test just to see if all the 150psi came up to the same level

#1 seems too high did it show signs of oil?

No not normal for any head port to have oil coating
Could be failing valve guide seal on #5 intake valve, vacuum in the intake manifold sucks in oil from valve cover area
Could also be from PCV valve hose, not sure where its connected on a 2006 3.0l intake, if its nearer to #5 then more oil vapor will go down that runner

I assume #5 spark plug tip also showed signs of oil burning

Yes, exhaust leak has a "ticking" sound almost like a lifter tick

Best way to find an exhaust leak is to have someone hold a GLOVED hand over the tail pipe of idling engine while you Listen for a change in the sound

Bank 2 is Drivers side so where #5 is, if it was burning oil that could cause issues with Cat Converters on that bank, i.e. P0430, or Cats could be OK and its just the oil that's causing the issue, but no way to tell which since you got the vehicle in this condition

 

Great advise From RonD above. When I was chasing a misfire on my 2003 3.0 it turned out to be an injector that was stuck. I discovered it by sending out my injectors to be serviced after 250K miles or so. By the way I just turned 292K miles! Once I got them back and they were all balanced the truck ran and still does really well. I posted the results in the forum here if you do a search.

 

Ron, I'm a little confused by this comment. In another thread (see here), I think you said it was normal for there to be oil inside the intake plenum and within the PCV tube. If I understand you correctly and my PCV valve is working, there should be a light coating of oil inside the plenum, right?

Thanks... still troubleshooting my misfire.

 

There is a difference, a light coating of oil is not desired but does happen as an engine ages and blow-by increases, which increases the amount of oil vapor in the engine
And some of this oil vapor can be sucked into the intake via the PCV system

The amount of oil in the intake can be an issue, especially if you are finding it in the head ports, the oil vapor should condense almost instantly in the much colder upper intake

No oil in the intake is best, but usually not practical since PCV system is required for emissions regulations, but you can install a Catch Can to help condense oil vapor before it can get into the intake

IF...........you notice oil just in one or two head ports then that's a sign of leaking Valve Guide seals, so not related to PCV system
The intake vacuum is causing liquid oil in the valve cover area to be sucked down the valve stem and into that intake valves head port, this can cause specific cylinder misfires and spark plugs in those cylinders will show "dirty" tips while other spark plug tips will look clean

 

Thanks Ron. Still troubleshooting this afternoon with a neighbor's help. Starting to pull the plugs again. Cylinder 5 spark plug looks clean - no sign of oil or coolant. Compression steady at 150 psi but Cylinder 1 is at 180 psi. That spark plug looked clean as well.

I don't have spare oil to try a wet test, unfortunately. My first test was on a cold engine with the fuse pulled for the fuel injectors. However, I must not have cranked long enough because see below! I think I do have low compression on cylinder 5.

Cylinder 1: 180 psi
Cylinder 2: 170 psi

Cylinder 4: 175 psi
Cylinder 5: 150 psi
Cylinder 6: 175 psi

 

Yes, that would be low compression in #5
Average of the 3 middle one is 173psi

so 150 is 23psi lower than average

 

Update: Good news I think.

Performed leaked down and it appears the leak is escaping from the #4 spark plug hole. I had both adjacent plugs in when I first did the test and I could hear a leak through the tail pipe, glove expanding fast, so I figured it was the exhaust valve issue. At first I thought I wasn't on compression stoke so I rechecked and same result. But I could still hear a lot of air quite loudly from the engine area so I removed the #4 and #6 spark plugs. Both were wet - smelled a bit like gasoline.

Continued leak down (re-checked several times) and with the #4 spark plug removed I can hear the air escaping from there pretty loudly and now hardly at all from the tail pipe (the rubber glove isn't expanding either). So what does that mean? Bad head gasket or cracked block?

What I thought was weird was when I checked leak down on #4 cylinder it seemed to be holding pressure fine. If there is a leak at the gasket, wouldn't #4 cylinder leak through #5 and vice versa?

 

Well if the #4 exhaust valve was open then its spark plug hole would be the easiest path out, via exhaust manifold, for the pressure, instead of the tail pipe

You can rotate the engine almost 180deg in either direction from TDC and #5 valves will still be closed, i.e. compression stroke and power stroke
And either way may close off #4 exhaust valve if that's whats happening, which I think it is

 

Ron, are you suggesting that I shouldn't remove the adjacent plugs to do this test? Because that's what I did at first and there was a definite leak from the tail pipe. So the problem is #5 exhaust valve then you think?

 

Oh, and I forgot to add: The reason why I thought I wasn't on compression stroke when I first did the test is because I was getting 150 psi compression but the gauge was reading nearly 100% loss. That didn't seem right to me.

 

Subbing. Interesting in seeing how this turns out.

 

By the way, I did the test on a cold engine. I know it's supposed to be warm but would it really make that big a difference?

 

I think I get it now. Thanks, Ron!
Guess that means new cylinder heads for me! Too bad Ford quit making them.

 

You should always test compression on a cold engine
All spark plugs removed
Hold gas pedal to the floor while cranking during test, this allows best air flow, but also turns OFF fuel injectors

Warm/hot engine test can be a secondary test if cold test was inconclusive, which it never is, lol

Glade you got it

#5's leaking air is going into the exhaust manifold and then making right turn into the open #4 exhaust valve and coming out its spark plug hole
Instead of making a left turn and heading for the tail pipe

 

As my old man was fond of saying, once in a while the old blind pig finds another acorn. Thanks for talking me through it.

EDIT: In case I wasn't clear, I was referring to myself :)

 

UPDATE:

Took apart most of the engine this weekend, down to the heads. I examined the push rods and they all seem fine. However, the finish on some seems to be flaking off. Is this cause for concern? Should I replace the push rods? Also, I have a set of Fel-Pro gaskets for the lower intake but I'm not sure I want to use those instead of OEM. Is there a consensus or recommendation for this gasket location?

I also discovered an annoying complication. The passenger side exhaust manifold has a bolt broken off in the far back location! My plan was to replace both heads. Can someone confirm that it will be possible to remove that head, with the exhaust manifold still attached, if I unbolt it from the exhaust piping?

 

Been using Fel-Pro for many years, no complaints

Yes, you can pull head with exhaust manifold attached, I usually have to on some engines because the manifold to head bolts are stuck and I don't want to strip the heads of the bolts or have them break off

 

What should I be looking for when examining the lifters? In addition to a faulty exhaust valve I was hearing engine rattle.

 

I had the same issue on the furthest upper driver side bolt just a week ago. The head on the stud broke off leaving a remnant stud. Was there before I even worked on the truck. Once you get all the other exhaust bolts off, the exhaust manifold can be pulled away from the head. Then you can remove the cylinder after taking out the heads bolts. You can get some vise grips and clamp on the remnant stud. Rock it back and forth from tighten to loosen, then you should be able to get it out easily, even using your fingertips as it is no longer under tension.

 

Mine has the bolt broken off inside and nowhere to grab onto with vice grips.

 

Oh, I see. I was under the impression that the the bolt that broke off fastened the exhaust manifold to the cylinder head. In that case, pulling the manifold away from the head won't work for you. Get some penetrating fluid, a drill bit, bolt extractors and a good impact driver and with some luck and elbow grease it should come out.

Sucks when stuff like this happens.

 

So how do I get the lifters out to inspect them? What should I be looking for?

 

Let me snap the instructions from the Haynes manual later today. I am going to do mine as well.