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Mazda MX-5 mk.1 spark plug lead change

Misfiring between 2000-3000 rpm suggested all was not well below the bonnet of my 1996 Mazda MX-5. On one journey, fortunately close to home, the misfire was so bad that it was reluctant to move above 3000 rpm at all, necessitating a gear change to force the revolutions up.

I had a new set of NGK BKR6E-11 spark plugs sitting around waiting to be fitted, but they didn’t seem to make any difference, so the next things to look at were the spark plug leads (also known as high tension leads). If the spark plug leads didn’t make a difference, the next thing to look at would be a coil pack; at over £200, this would be getting costly. So, at about £30, it made sense to try changing the ignition leads first. Again, MX5parts provided the spark plug leads at a reasonable price.

As usual, changing them was a simple task, but here are the photos anyway. If you need further guidance, you might want to consider buying the Veloce Mazda MX-5 1.8 enthusiast’s manual, or alternatively the 1.6i enthusiast’s manual, should that be more applicable.:

Spark plug leads ready
1. Spark plug leads ready
2. Old spark plug leads in the engine
2. Old spark plug leads in the engine
3. Remove electrical connectors; twisting them may be required
3. Remove electrical connectors; twisting them may be required
4. Grip tightly and remove each lead from engine
4. Grip tightly and remove each lead from engine
5. Reverse the process with the new leads
5. Reverse the process with the new leads
6. Step back and admire the new leads
6. Step back and admire the new leads

You can probably see from the last picture that the leads are a touch on the long side for the MX-5; I suppose that’s the result of buying budget leads.

As far as performance goes, however, the engine seems much happier. Not had any misfiring yet, and the engine is a lot happier at low revolutions, allowing me to stay in a lower gear. That, I believe, is having a positive effect on my fuel economy: by my calculations, since changing the leads and plugs, I managed over 30mpg from my 1.8i for the first time. And that’s without any motorway cruising, albeit a bit of dual carriageway driving.

Your mileage may vary, quite literally; let me know how you get on!

Mazda MX-5 mk.1 1.8i (1840cc) air filter change

When it comes to servicing one’s own car, the air filter is normally just about the easiest thing to change. Despite this, it’s often overlooked by lazy owners. Having a clogged air filter can increase fuel consumption and reduce power: it really makes sense to change it regularly. Fortunately, changing my Mazda MX-5 1.8i Merlot’s (also known as Mazda Miata in the U.S.A., and the Eunos Roadster in Japan) air filter was extremely straightforward.

My Veloce Mazda MX-5 1.8 enthusiast’s manual (you may want the 1.6i enthusiast’s manual instead) recommends inspection of the air filter every 6,000 miles. It should apparently be changed every 27,000 miles or 3 years. Armed with the workshop manual and a £12.77 brand new genuine Mazda air filter from MX5parts, I set to work.

Chances are that you could figure it out yourself, but on the off-chance that you’re somewhat timid or cagey about fiddling with your own car, here’s a step-by-step guide. (Usual disclaimers apply.) Apologies for the poor-quality camera-phone pictures.

1. Unplug the electrical connector
1. Unplug the electrical connector
2. Release the clamp
2. Release the clamp
3. Detach the trunking
3. Detach the trunking
4. Undo the four screws of the air filter casing
4. Undo the four screws of the air filter casing
5. Lift the casing up
5. Lift the casing up
6. Remove the air filter and any debris
6. Remove the air filter and any debris
7. Insert the new air filter
7. Insert the new air filter
8. Put screws, trunking, trunking clamp, electrical connector back
8. Put screws, trunking, trunking clamp, electrical connector back

That’s it! Drive off laughing like an idiot, enjoying the happier engine—and the consequently restored power.