Spark plug wire install

[Portugal_Disco]

I am experiencing a misfire on my #4 cylinder. I am going to start with the basics, replacing the plugs and the wires first. With the plug wire removed I found some corrosion under the boot, more than likely the root of the problem. I know exactly what I need to do (in theory) in order to change the plugs and wires.

I have never changed plug wires on a disco before and I am running into slight challenge. "What needs to be removed or done in order to reach the coil packs?" That happens to be so conveniently located!!!

My nerves are beginning to run thin with this seemingly easy fix. I wish I had more time on my agenda to tackle this bear. I know there is no easy way to do this but any tips would be great.

The Un-Shade tree Mechanic,

[Disco Mike]

What a way to spend a weekend. There are 2 ways to replace the plug wires, 1, either have a very small hand and remove one wire at a time from the coil packs behind the engine on top of the transmission, or remove the top half of the intake manifold and then you will have better access, both ways are a bit of a bugger.
Mike

[Portugal_Disco]

Mr. Mike,
Thanks for giving me the tip I have been searching for... I tried reaching (squeezing) my hands in there today with no avail. What I ended up doing was opting for the quick fix until I can work in some more time to do the job right.

I disconnected the plug wire and had to literally cut the boot off the wire because it was so hard and brittle. Once that was done I removed the metal lead and gave it a Coke a Cola bath with a wire brush scrub. I then snipped about 3/8" of the wire (making sure not to cut it to short) until the corrosion was not visible. The metal lead was crimped back on and a boot from the new wire set was slid into place.

Once all was done a spin around the block, provided a lot less vibration and power restored. This was the quick fix that should get me by until next weekend when I can remove the intake manifold and do the job right.

Thanks again for the info Mike,

PD

[Dan Erickson]

I have tried both ways and I have to say that cleanest and easiest way for me, was to take off the upper air intake to expose the coil pack.

The following is a post that I made over on D-web.

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I replaced mine with 8mm Magnecores a while back.

I really could not see how it could be done very practically without removing the upper air intake (I tried for a while, but my hands suffered).

The upper air intake is really not that bad at all to remove (may want to have a gasket handy for refitting though).

I have had the upper air intake off about 4 or 5 times now and here are a few things that worked for me:

-When removing the upper air intake there is a stud off of the passenger side of the intake that needs to come off. (This secures the metal coolant lines to/from the heater matrix). I remember it being a little tricky (I think), so I left it off to make future intake removals easier. The coolant lines seem plenty sturdy with only being bolted to the accessory drive bracket.

-Removing the entire plastic portion of the air intake from the air cleaner to the throttle body (including MAF sensor), just keeps things out of the way.

-Disconnecting the hose from the IAC valve to the upper air intake makes it much easier to get at the bolt under it.

-After disconnecting the return line from the throttle body de-icer, I pulled the plastic line all the way out and tied back. This helps when refitting the upper air intake as it can get in the way of setting it in place. After the intake is refitted the line can just be poked back through and reconnected.

-Removing the four screws holding the coil pack on, helped me to move it around a bit when unplugging/plugging in the wires and is also necessary for removal of the upper air intake as the top ones bolt to it. The two on the top were easy to get to using an 8mm socket with an extension and a swivel (on the socket end). I remember the two on the bottom being a PITA, so they never went back in. The bottom of the coil pack has a clip that clips onto the fuel rail, so I thought that between the top screws and the clip there was plenty of support for the coil pack. The coil pack has to be pushed/tilted back out of the way in order for the intake to be removed.

-After disconnecting all of the other obvious things like connectors for IAC, fuel purge, TPS sensor, brake booster, the other hose for the TB de-icer, and both throttle cables, the intake should be ready to unbolt and remove. Unclipping the wiring harness on the fire wall and letting it rest on top of the clips helps to keep it out of the way during removal.

-Once the intake was removed I put a towel or rag over the lower intake ports to prevent anything from dropping down there (I know it's just common sense).

-It helped for me to climb in from the front and lay with my belly/chest on the alternator/AC pump and look directly down to see the top of the coil pack. At this point, I pulled the wiring harness on the fire wall toward me to get a better look.

-I removed each wire working from the top outer, then top inner, bottom outer and finally bottom inner. The reverse of this should be the order in which they are refitted as it prevents wires from obstructing your view or getting in the way of the one you are working on. I labeled each wire as I took them off the spark plug end, and matched as well as I could with the new ones (not a perfect match with the Mags). I wrapped a piece of tape on the coil end of each new wire and marked with wire number. I wrapped the tape in such a way as to leave a tab that could easily be flipped/turned to make reading the number easier.

-I actually connected each wire at the spark plug end and had the other end of each group bundled near each end of the coil pack, so once I was laying across the engine, I did not have to get back down for anything.

-I put some dielectric grease in each of the plug wires which made plugging them into the coil pack much easier (just don't get any on the outside of the wire, or it may be hard to handle them).

-The RAVE CD has a picture of the wires connected to the coil pack (as looking from the back of the truck). Printing this out and having it up in the engine compartment with you helps alot. Not only does it show the correct numbering, but it also shows the proper routing of the wires, which also helps to keep it orderly.

-Again, working from the plugs in the bottom center of the coil pack, then bottom outer, top inner and finally top outer makes installation much easier.

-Being able to move the coil pack around a little while fitting the wires also made it easier for me.

-It’s a good idea to make sure the coil pack is pushed back out of the way before attempting to re-fit the upper air intake (it burned me a few times).

I have to say that doing the work up front to get the upper air intake out of the way really seemed to make actual replacement of the wires rather painless and orderly.

As I said before, this is what I have found to work for me. Others may not agree….

Dan

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Glad your quick fix seemed to work.

Hope this helps when it comes time to replace all the wires.

Peace,

Dan