Is Your BMW Tii Feeling Sluggish?
When driving off in the morning do you notice a lurch and a definite loss of power when your tii’s cold start valve shuts off?
One possible cause is a faulty delivery valve in the injection pump.
A quick check is to disconnect the plastic fuel lines from the pump — use a 14mm open-end wrench on the fuel line coupling while keeping the delivery valve from turning with a 12mm open-end wrench. Disconnect the coil wire and turn on the ignition just enough to start the fuel pump.
Do not turn the engine over!
The injection pump should remain completely dry. If gas sprays out of one or more delivery valves, see if the threads are wet where it screws into the injection pump. If they are, tighten.
If it leaks out of the top, replace it (about $4 at your dealer). When you reassemble, do not lose the very thin sealing washer that goes in the threaded recess on the pump. Use Lubriplate on the threads and tighten only until there are no leaks.
Check once with just the fuel pump running before connecting the injector fuel lines and once again after the lines are connected, with the engine running. Try not to distort the plastic injector fuel line when tightening. Make sure that the plastic lines do not touch each other since normal vibration will have them wearing each other through.