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spark plug questions

5K views 6 replies 5 participants last post by  Crew Chief 
#1 ·
Ok so my plugs are due to be changed on the 4.7 2006 so i decided to do it myself so do i have to disconnect the battery cable before starting and do i have to take off the cable on each spark plug boot and do i have to remove and replace in firing order, i just dont want any complications.

Thanks Connor
 
#2 ·
No need to disconnect your battery. Just remove your air cleaner ducting, the coil pack and replace your plugs. I'd recommend replacing one at a time, start in the front where they are easier to reach so you build your confidence in what your doing as you go. Make sure to buy pre-gapped plugs (I picked up a set of platinum Bosch for my upper bank, mine has 16 plugs in the 4.7 L, they cost around $3 a piece). Gap should be .044 If you have some anti sieze put a very small amount of that on the plug threads before installing the new plugs (its a pasty gray looking compound). Don't overtighten, you should only use a 3/8 socket set so you make sure you do not tighten too much which would cause a stripping of the threads in the boss on the head (very, very, very bad thing to do!). Once you've replaced them all (approx. 1 hr) reinstall all the items you took off in reverse order taking care to not overtighten any of those bolts too. Hope that helps. I'm sure someone here has done a better write up than me, so you should look around on the forum search and see, maybe you can also find pics.
 
#4 ·
No need to replace them in any order, but like suggested, do them one at a time, i.e. disconnect and reconnect the cables before moving on to the next plug. That will prevent mixing up cables and that can be mess if you do.

Keep in mind, the ignition cables do wear out, with use and time, replace them when the OM says to do it. If you've only put 30k miles on a vehicle in 5-6 years, cables may wear out before the 30k miles.

Have a helper start the motor while you watch it, in the dark, see if you see sparks leaping from the cables, if you do, they are past worn out, replace them.
 
#5 ·
Don't spend too much time looking for sparks.

06/07 4.7's and all 5.7's have no plug wires......Coil on plug systems.

3.7's have three Coil on plug and three plug wires leading to the other side if memory serves.
The 08/09 4.7's have a plug wire leading from each coil to their secondary plugs on the sides I remember.

Rob
 
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