Stumble / Hesitation Upon Starting

From BMW E34 Encyclopedia

Overview[edit]

This section will attempt to identify possible elements causing hesitation or stumble when starting the car.

Basic Maintenance[edit]

The first thing is to see when was the last time you performed basic maintenance. Make sure your spark plugs, oil, coil, and coil boots are in check. Running summer oil in winter will cause the engine to turn over at a slower rate.

Battery / Alternator[edit]

  • Check the battery acid level
  • Clean the battery terminals and make sure the connectors are not-rusted and tight
  • Check the negative battery cable and make sure the other end is making proper contact with the car frame
  • Check the voltage across the battery terminals
  • Check the belt driving your alternator, a loose belt will slow down the battery recharging process
  • Turn on your high beams and start the car, if they dim then your battery does not have enough charge for proper vehicle operation
  • Get a free alternator and battery load test at your local auto parts store (do not forget to tip)

Air / Fuel Mixture[edit]

Rear Main Oil Seal[edit]

Leaking rear main oil seal will coat your starter in oil. Jack up the car and look at the starter. If it is covered in oil, use an electrical cleaner and spray it all over the starter to get you moving. Inspect condition of starter wiring.