04/16/2026
For the young techs always verify your cranking compression with a running compression test. This is a fiat came in with a skip on cylinder 4. Cranking compression showed 120psi that should be enough to run smoothly however running compression showed 20 psi. Which is a valve train issue in this case the intake cam lobe on cylinder. 4 cracked and shifted on the cam shaft. The shaft is turning but the cam lobe no longer rotates with the shaft. This is going to be a common issue as many engines no longer use a one piece cam shaft but a multi piece pressed together unit
