Truck is a '94 F150, 5.8l, E4OD...tonight I took my inner wheel well out to gain better access to the passenger side exhaust manifold. It's always had a tick, under load only, and since the 5.8L engine is notorious for cracked and broken manifolds, I figured that's what I was dealing with. So I get the wheel well outa there and scoot in with the light and a can of PB Blaster to hit the bolts/studs and get 'em soaking. As I head from the front of the truck to the rear, I notice that the "well" for the furthest spark plug is black and sooty. None of the others look like this. There is soot on the plug wire boot, the area of the head, and on the body of the plug. The soot is a full 360* in the "well" where the plug hole is in the head. Put a socket on it and it seemed tight. Took the plug out and the electrode looks fine. It's a type of plug that doesn't have a crush washer, but a beveled surface that seals with the head. Could that SOB have been not torqued correctly (aka loose) and the source of my tick?

I was inspecting the area around the exhaust manifold to see if I could see any areas/spots that were 'dumping' carbon that would have been indicative of a crack or leak and that's kinda when I saw 'what didn't look like the rest'.

Value your opinions and need to hear them before I tear into this any more than necessary.

Thanks....and have a great (and safe) holiday!

 

you might have a funky connection in that boot. Since you have taken out the inner wheel well already you might want to take the opportunity of "one time access" to replace all the plugs and resistor wires on both sides. If the wires are original then it's time for a new set, distributor cap and rotor anyway, 100k recommended maintenance. A new set of OEM spec will run you $40 for the wires and about $30 for the dist cap and rotor. I recently "bit the bullet' and bought Mallory sidewinder wires and a new MSD brass pole distributor cap. (about $ 150 all together, lower impedance from dist connection to plug). BUT: I cant see why you would be getting ticking only under load if the plug was not properly seated. If the plug had failed it would have looked gunked up and you would have set off a sensor (at least in my 96 302 the sensor picked it up). It may be that the manifold only ticks when you are heavy revving in lower gear under load and the leak is blowing right on the resistor wire boot. It could be that you have larger than spec tires and that is putting stress on the engine under load and compression is escaping somehow through a defective plug. It could be that the plug seat is poorly shaped and, again compression is forcing out only under stress. But usually if it is a faulty plug it just gets worse and worse. Either way if one looks radically different than the others I would replace the whole shebang and see what happens. As my friend from NH says "why wouldntcha" ??

 

Turns out it was the back two manifold bolts. They were both loose. I torqued 'em to 35 ft.lbs, put everything minus the wheel well back on for a test drive. Just a very faint tick when cold that completely went away when warmed up. Back home, I put about 10* more torque on 'em and am calling it good for now.