[garaetjjte]

Technically diesel engines do not strictly "engine brake" because of lack of throttle plate, and thus lack of pumping losses. However that doesn't mean that it won't slow down: friction losses, heat loss to cylinder walls, etc. still occur. Surely diesel passenger car will decelerate stronger when left in gear than in neutral. Given how many pages and pages of discussions you can find people arguing whether petrol or diesel engines brake stronger, it seems pumping loss doesn't make that much difference.