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Mazda MX5 NC Oil change and Stereo Install

So yesterday was obviously the day of the MX5.

I started the day by going to work and whilst there i did the much needed oil change on the car. According to the JDM as fck sticker it was almost due for its change anyway, but it’s been running on 0W20 (which in my opinion is far too thin for such a high KM engine).

So now its running some lovely fully synthetic 5W30. Since i got the car its always had a lifter chatter when starting hot or cold, obviously until the oil circulates to the head, but since the change it seems to have stopped that and the engine is now quieter in general. Great success.

Not a hard change to do. I found it easier to remove the 5x 12mm bolts and pull off the plate under the sump. It does have a cutout for the drain plug but it’s tiny (it’s the oval hole on the left in the photo below) and i didn’t want to risk making a mess if the super hot oil flying out of the hole clipped the edge of the plate. It also helps with access for the oil filter.

It’s all pretty standard stuff to drain the oil. The hard bit is not making a mess with the oil filter. The filter is very accessible, but it sits right above the crossmember meaning that if you do nothing but spin off the filter, you will get a fair bit of oil pouring on/into the crossmember and making a hell of a mess. Theres heaps of opinions of what to do here, ranging from using plastic bags to buying special funnels. In my case i decided to get crafty and use a scrap of cardboard about 30cm long. Fold both sides up along the length and then slip it in from under the sump up to under the filter. It’ll then direct all the oil that comes out, under the sump and straight into your oil catch pan. This also leaves you with access to the filter from behind the crossmember without getting in the way of the draining oil.

Sadly no photos because oily hands and only having my phone as a camera at work.

Whilst at work i also decided to replace the main battery. When i got the car i noticed that the battery was the original, 9 year old Mazda battery, so i had no faith in it at all. I’ve had bad luck with being stranded in my previous cars thanks to bad batteries, so ive taken to changing them if they haven’t been changed in a couple of years. A nice new NS60 battery and away i go.

Once home i chucked the car into the garage and wound the top down. Love having such nice easy access and lighting without the top on. It was time to change the stereo. This is a well documented process so i wont go too in depth, but this is what i experienced.

So the car is fitted with a Pioneer JDM avic headunit with Bose. The whole car is wired with the Bose system, meaning it has 7 speakers (2 per door, 2 in the rear and one in the centre of the dash) and an amp to drive them all. This means you cannot just wire the headunit like normal, running all the speaker wires from the headunit into the wiring in the dash. This would result in over driving the Bose amp (running an amplified signal into an amp) and would mean there is terrible static coming from the speakers at all times. To correctly wire them up you need to run the speakers from the RCA preout on the headunit (this is why i got a headunit with 3 preouts, front, rear and a sub if i want one in the future). This will feed the amp a line out, unamplified signal which it loves.

The original setup also had a crazy Japanese lady that beeped loudly and then proceeded to angrily tell me something i couldn’t understand, every time i turned the key on. Annoying was an understatement.

Ive been gathering bits for this for a while and i finally got the last bits the other day.

This is what i have.
JVC KD-R971BT (bluetooth, color changing, 3 RCA preouts)
Two wiring harness adaptors
Four pairs of RCA plugs
A universal din pocket
An Axxess ASWC-1 steering wheel controller

The reason i have two harness adaptors is that you need to depin a couple of pins from one and move them to the other. The harnesses are missing two pins for the steering wheel controls, and some early ones (not mine) are missing the one to trigger the Bose amp.

Depinning them is a prick of a job but i managed it with a very small jeweler’s flat blade screwdriver. Once the wires are out you flick the locking tab back out and slide it into the harness adaptor you’re using. The two wires i had added are the red and blue on the left in the centre.

Once that’s done i started on the wiring for the RCA speaker connections. I tied back all the speaker wires (not used, as described above) to keep them tidy.

I love my parrot.

It was then time to add the steering wheel controller. Following the instructions on the website, all i needed to connect was ground, switched 12v and the wiring from the “steering wheel remote” connection on the JVC harness. Easy.

Once all the wiring was done it was time to move onto removing the old headunit. First you remove the two little trim panels at the sides. They just pop off with some gentle persuasion.

And then if the stereo is original, you swear and wish you hadn’t started this project. You have the bitch bolt to remove.

This is a bolt that secures the back of the stereo into the dash frame. Apparently it’s to make it harder to steal, but cmon. Whoever designed this setup is a sadist. You need to remove the trim under the steering column, and then blindly feel around for the bolt.

I captured this photo with my phone, so that i knew what i was looking for. It’s tucked will into the dash, and is only accessible blindly with a really long extension on a ratchet. Its the 10mm bolt on the left, in the distance.

Once you have that out, a couple more easy to get at screws and the whole lot would (forcefully) pull out of the dash (remember to disconnect the HVAC wiring).

This clusterfark is whats left once you pull the stereo out. A big lump of wiring and heaps of little ones for the GPS, ETC, park brake, speed etc. All of it needs to go.

I removed the standard headunit from the frame and installed the new headunit and pocket.

And then this is where it all turned to shit. I plugged it all up in the car to test.

I had power, and i had some sound. The sound was only coming from the RH side of the car, with nothing at all from the left. I also didn’t have steering wheel controls. the unit powered on but just flashed rapidly red/green. Found the steering wheel control issue easy enough, the pin i added to the harness had been pushed out when i plugged it into the loom. Fixed that and the steering wheel controls worked automagically. Still no sound on the left though.

I pulled it all out and checked the wiring. All seemed to be OK. I decided to test the amp by running speaker wires straight from the headunit into the loom and seeing if i had sounds. Sure enough i had sound, albeit with the terrible static as mentioned earlier. So the amp was accepting an input, but the headunit wasn’t giving it.

I tested all the RCA connections with a multimeter and i had good continuity and no shorting, but still no sound on that side.

Maybe it was the headunit then? I tested all the RCA preouts with the working speakers, and all of them were putting out good sound. So not the head unit then.

What the frack. I was at the end of my tether, i just couldn’t understand it. This is about where i gave up and went and had dinner. Not before the damn headunit slipped and scuffed the lovely shiney brand new display. FML.

Whilst eating dinner i had a thought. I need to test with a new RCA plug and wires.

After dinner i set myself a goal. I had an hour before i had to give in and leave it for the night (i’d been working on it for about 6 hours at this point).

I quickly rigged up a new RCA plug and some wires and connected it all up.



So, despite testing OK on a multimeter something was still wrong and two of the RCA plugs were DOA. I replaced them (with new wires i depinned from the other harness adaptor) and all is working now. Ran the wire for the BT mic, jammed it all into the hole and screwed it back in. Looks lush.

Its fully customisable for color, so ive set it to somewhere close to the color of the dash at night. It blends in nicely. You can even set different colors for day and night, and it dims with the headlights. I don’t think the speed sensitive sound will still work, but somehow it still changes volume when i put the top up and down like the original one did, so i guess that’s built into the amp.

Im very happy with it now. The sound is crisp and clear. I just need to tweak all the settings and i’ll be good to go. No more super aggressive Japanese lady either.

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3 years ago

This guide was super thankful on my 2006 NC, with bose. Thank you for sharing. The pics were helpful