Under the thick plastic engine cover, hides the various gubbins for the direct injection system, but surprisingly also a large portion of the wiring loom. The loom is inside a plastic case, which after years of living with the heat trapped under the engine cover, becomes brittle. Mine already shows some patina.
It's made of that soft, floppy plastic, and at 9yrs old, mine is brittle to the point where it'll shatter into a zillion pieces if say, if you stare at it for too long or if a butterfly lands on it.
A new one is only $85 and replacing it is a simple enough procedure, if you're patient.
The old part has a top cover which clips on, and the first step is to remove it. But in my case, the plastic was so brittle that just prising the clip a tiny little bit, would see it snap off. So the top cover comes off pretty easy!
Where the loom exits the harness cover, in some points the bunch of wires are taped to the neck of the plastic and at other spots there's a slot in the plastic where a cable tie passes thru. Whoever was incharge of applying the tape at the factory really loved his job, since it's several mm thick. I'd suggest taking the long route and carefully unwinding all the layers of tape; if you are going to take a short cut and use a blade to cut through it, be super careful that you don't nick any wires.
Actually the bottom comes off easy too...it's bolted onto the manifold at 4 points, so you remove the nuts and to avoid stretching or stressing the wiring, it's easy to just break the plastic into several pieces where they can be removed gracefully.
The now-denuded wiring harness in all its glory. The plastic cover does deserve some credit, as the wiring is still supple and doesn't seem too heat affected.
The old harness cover came out in pieces, but the new one has to be inserted in one piece 🙂 So to make some room, I disconnect all the wiring loom points at the front of the engine.
And unhook the harness from its various holders around the engine bay
This gives just about enough wriggle room to slide in the new part under the harness. Thankfully the new part is flexible enough that you can twist and flex it to fit underneath, without tugging on the wiring too much. Having a second person gently lift the wiring while you persuade the new one into place is a big help, and doing it this way means you don't have to take any chances with removing any of the the brittle plastic wiring plugs from on top of the engine.
Once it's in place, make sure the wiring is all happy and relaxed, that none of it is stretched or might poke out of the cover when you clip the top on.
Re-tape the harness to three of the necks of the wiring cover, and another 3 exits have a slot where you can snug up the wiring with a cable tie.
And we're done!
Fingers crossed this is good for another 10years, and while I'd say this is a straightforward job with a 2/10 for technical difficulty, it does also require a 9/10 for patience 🙂