mx5cartalk.com

After checking everything was connected and tightened at around 8pm last night, I started her up. The engine started first go but it stuttered and stammered like it was having a missing cylinder. I double checked the spark plug firing order and the vacuum hoses. It continued to carry on for a couple of minutes. My heart sank - oh no, I didn't really want to tear it apart again.

Just to be sure, I put a paper clip across GND and TEN in the diagnostic box and connected the timing light, and guess what? She suddenly purred like she should be. All was in order. I think the stammering was due to excessive fuel drawn into the cylinders when I turned the crank many times to make sure I had the timing right. But then this is a fuel injected car, and how could fuel be drawn into the cylinders with the spark plugs removed? The paper clip across the diagnostic terminals obviously overwrote the computer and burned the excessive fuel away.

Learning from Stan's experience, I made sure I tightened the tensioner pulley before I buttoned her up.

There were some fine metal filings in the timing belt compartment. The culprit was the tensioner pulley. It just had it, and it could be spun freely by hand. A brand new one can hardly be spun by hand.

where did you get all your stuff from?

Did you replace all the pulleys with new ones?


That sinking feeling..... I know it well . But 2nd time around was a lot quicker

Stan I got my my parts from my local Mazda dealer. I also bought the o-ring seal for the waterpump at the same place.

All up, the parts cost me $470 with a 15% club member discount. They used to give me 10% discount but I guess the bigger purchase allowed me a bigger discount.

saboteur and I did his timing belt the few days before the skidpan day, as his timing belt had snapped. The old tensioner and idler pulleys were rogered! They scratched and ground as they turned - just spinning them made all sorts of scratchy noises. The engine had done 260,000KM+ by this stage, so it was fair enough that they had worn out.

The original ones from my engine were fine, but in the interests of sanity and a fresh new engine, I replaced them anyway. It's just a shame that you can't check them without pulling the thing down.

The tensioner and idler pulleys cost about $90 and $80 respectively, not exactly low cost items considering their sizes. They were not changed at the 100K mark. Considering the harsh engine sound before the swap, I will definitely change them again at the next 100K mark. Besides, I don't like to see powdery metal bits at that part of the engine compartment. I hope none traveled up to the overhead valve train.

The new pulleys plus a brand new set of Yokohama C-drive tyres make my car sound almost like a quiet sedan at speed!