This is the original 1.8 4cyl that was in the B3 80 Quattro. Not a bad little motor really. When it came to us someone had been clearly having a play trying to get it to idle, but missing the actually cause of the problem. The rubber boots connecting the fuel metering and the intake are notorious for developing small cracks over time, which is what had happened to this one. Sourcing a new one sorted the vacuum leak, but there was still something not quite right at idle.
Investigation revealed someone had been playing with the adjustment screw inside the air meter. They had not replaced the small plug which keeps water out and it had seized. After taking apart the unit and carefully freeing the allen set screw it could finally be adjusted. After that, this little motor ran sweet, although it just wasn’t quite exciting enough for future plans…