Shady Cadence

Not if cranking rpm was slow enough to not create the bind. I've seen some weird $#!%.

Runner4Luke

TPS was adjusted last week as well.
But that buffeting AFM seems like an extremely strong indicator.

bswarm

That's when it's most noticeable, when you quickly hit the gas it makes a popping noise in the intake. But, don't get that confused with an ignition misfire, it sounds louder with a sticky valve. I'd take it somewhere to get hooked up to a scope to make sure it's not an ignition misfire before you pull the head .

RedRockWarrior

My truck would fire for a long time and ended up having bad plugs and wires

Runner4Luke

The buffeting occurs as the throttle is released and rpms drop. I can hear what sounds to be the flapper in the AFM smacked closed and open. Sounds is coming directly from the AFM.
Like the intake valve is sticking and pulsing pressure into the intake manifold.

robm

Did you check your vf signal yet? That will tell you if it's running lean or rich. Heres the writeup, http://www.well.com/user/mosk/Vfsignal.htm

Runner4Luke

That's a good write up, and no I haven't verified the mixture quantitatively like that, I have however forced mixture changes by increasing fuel rail pressue and manual swinging the AFM about while idling. Engine rpm responded as expected, but still never fired on number one.

Runner4Luke

Changed out those driver kick panel grounds, no change.

Runner4Luke

Yep, sticking intake valve. Check it out. Didn't happen this time, but I could hear the intake screech a couple times as it closed.

bswarm

Video won't play. It says it's set to private.

bswarm

Do you have a vacuum gauge? You should be able to see the vacuum jump up and down when the valve sticks.

Runner4Luke

Video should work now. No I do not have a vacuum gauge.

robm

So, what causes the valve to stick?

Runner4Luke

Lot of carbon build up after lots of miles I would imagine, or something along those lines.
But this obviously isn't the case here as the head has less than 700miles.
It's gotta be a manufacturing defect. I mean the valve literally screeches.
I'll be placing a call to Ted tomorrow.

robm

Nice find! Mines identical, just didn't know that was the sound a sticky valve makes.

robm

Mine has a measly 50 miles on complete rebuild.

Runner4Luke

Did you also do running compression test?

Runner4Luke

Thanks everyone for the suggestions, I'm not sure how long it would have taken before I figured out the sticking valve. Although it seems so obvious now, guess that's always the case.
Glad to have it figured finally, been dumping countless hours into this since the head was put on.
Thanks again!

Odin

Wow, after dumping that money into a new head, new gaskets and such that suuuuuuucks!
I wonder how much of that they'll cover, probably just the head if it was assembled when they got it. If they did the machining and installed the valves I would hope they would cover a little more than that, maybe give you a head gasket?

Did you get the Pro-Topline head or their OEM Replacement?

Shady Cadence

Awesome, we have evidence and an answer. I figured it had to be an obscure management issue or a mechanical problem.

Sometimes you gotta reproduce the problem conditions completely before you get answers. Again, good work man.