What I Found Under the Hood

With the hood open, the first thing we noticed was the cheap battery. Whoever owned the car before did not care enough to put a decent one in, and the result was poor starts and inconsistent running. It was the cheapest model available, 899 NOK (about 75 euros), and there is no telling when it was last changed. We swapped it for something better.

Next was the intake. We took the manifold off to inspect the intake valves, and as expected they were filthy, with several lines and seals that needed replacing. We also took the cylinder head cover off, and the seals were crusty and had probably never been changed. All of that is part of the service anyway.

We did a leak-down test and there were no major issues. Cylinder 3 in particular showed no leakage.

Then back to the intake valves, which were filthy. We looked into it and settled on soda blasting, which uses sodium bicarbonate particles to clean surfaces without damaging them.

Before blasting we closed the valves properly, checking the camshaft lobes were both pointing upwards. Then we sprayed brake cleaner into the intake valve holes, let it pool, and used steel brushes and picks to scrape the carbon off. After about 10 minutes of that we dried everything and got ready to blast.

To avoid spraying soda all over the engine bay, we 3D printed an adapter connecting the vacuum to the blaster:

We spent 30 to 45 minutes soda blasting the valves. It worked well, though some manual scraping was still needed afterwards. The valves came out much cleaner.

The hope is that this clears the misfire and improves the compression test numbers.

More soon.