Cracked distributor cap source of vacum leak? [Archive] - Bimmerfest - BMW Forums

Cracked distributor cap source of vacum leak?

11-19-2008, 02:28 PM
My 1992 535 e34 M30 has a cracked distributor cap and is worn inside from the rotor. Real bad. Can this cause my misfiring and rough rough idle issue? I was also wondering if having a cracked cap could be a source for a vacum leak?

11-19-2008, 04:49 PM
Definitely could cause rough running or mis-fires, especially if the rotor is worn badly. You can also get 'tracking' from the carbon brush deposits. I don't see how it could cause a vacuum leak though.

11-20-2008, 06:54 AM
Lots of tracking infact there were carbon deposits everywhere. It looks like something broke off or came loose, the rotor wore a pattern in the plastic case of the cap. I have a replacement on the way so hopefully it will be running smooth again.

11-20-2008, 06:18 PM
Be sure to replace both the Cap & Rotor. If the rotor was touching the cap, then you had better check the Rotor Shaft to make sure there is no excessive play in the bearings. Unless the cap became loose or the rotor broke apart they should never actually touch.:eek: