New owner checklist

This is a list of items that should be checked over when you take posession of your new (to you) 912E. If your car came with a full and well-documented service history and is running smoothly, you may be able to skip most of the items. However, if you have no idea of your cars service history, and the car is running poorly, start by getting the ignition system into tip-top shape. Next, make sure that the engine is free of vacuum leaks. Only then should you move on to diagnosing the fuel injection system.

The obvious

  • Change oil and oil filter
  • Change air filter
  • Adjust valves
  • Check/replace/adjust ignition points
  • Check/replace distributor rotor
  • Check/replace distributor cap
  • New (correct) spark plugs with correct gap
  • Check/replace spark plug wires
  • Set the idle speed
  • Set the timing

The not-so-obvious

  • Put new gaskets on the oil filler cap. The Type IV engine is very susceptible to any sorts of air infiltration, leading to poor performance.
  • Check fuel lines - a cracked hose or very old one can crack under pressure and leak fuel and cause an engine fire.
  • Check the fuel rails - if they are rubbing against any part of the engine they can wear and leak - same disastrous outcome as above.
  • Brakes - flush the system with new fluid. Replace the flexible rubber brake hoses (ideally with flexible stainless steel hoses), check the pads and rotors.
  • Check your front wheel bearings for grease and adjust.
  • Get a good alignment.
  • Replace fuel filter (Bosch part number 0 450 905 062).
  • Put a bottle of Techron in a full tank of gas.

Car running poorly

  • Check for vacuum leaks
  • Check Air Flow Meter - check that the flapper moves freely and is not warped
  • Check/replace Head Temp Sensor II
  • Check for leaks in exhaust system

A lot of people dislike the Bosch L-Jetronic fuel injection system fitted to the Porsche 912E (and the VW Beetle, Super Beetle, and Bus). However, most of the complaints seem to stem from the fear of the unknown. Unfortunately, this fear often resulted in the replacement of a superior system with an inferior aftermarket carburetor set-up.

In reality, the L-Jetronic system is very simple, very reliable, and easy to diagnose. All you need for diagnostic tools is a fuel pressure gauge, a multimeter, and a manual. The Bentley manual does an excellent job of explaining FI diagnostic procedures. Most people blame ignition system problems on the fuel injection and go on a parts-replacing spree, unnecessarily wasting money. So it is imperative that before diagnosing the fuel injection system, the ignition system must be in tip-top shape and the engine must be free of vacuum leaks.