Fouled plugs low boost? [Archive] - Bimmerfest - BMW Forums

: Fouled plugs low boost?

the governor
05-12-2008, 06:55 PM
Would fouled spark plugs cause low boost. I should be seeing 8.5-9psi and lately its been 7.5-8psi. I changed plugs from fouled Bosch Platinum +2 to a cooler NGK plug. Since the switch the boost is back to 8.5-9psi. Would bad plugs have caused this?

05-12-2008, 07:23 PM
bad plugs = misfire. misfire = power engine performance and poor manifold vac/pressure. poor manifold vac/pressure = low boost

the governor
05-12-2008, 09:29 PM
The DME never registered any misfire codes. Would the DME retard the timing to avoid misfires?