When the weather gets cold, more and more often problems with the performance of cold engine arise. Beginning of topic you can read here, but how – what to do, if the situation turned out to be more complicated.

It can happen, that problems with leaking injectors are so significant, that damaged cylinder (or even more often – other cylinders of the same bank also) start to miss cycles – group misfires appear, MSD80 “turns off” “damaged” cylinders etc. The situation becomes such inadequate, those online diagnostics don’t give an exact answer.

Good news – it is quite easy to identify the “guilty” bank: Lambda and the according integrator has significant differences from correct values (see Part 1 of the topic).

When the guilty bank is identified, proceed as follows:

Screenshot: YouTube; BMW Check


take out the injectors and attach them as seen in the picture. The injectors, which are leaking in the closed position, can be identified immediately when starting the engine.

If this test doesn’t help to find the guilty injector, you can attach the control signal, insert the injectors in a glass bowl and repeat the attempt to start the engine.

Injectors, which are performing correctly, has to have two alike, symmetrical fuel bundles.

If any of bundles is non-symmetrical; the fuel is not injected with fine drops, but leaks with jet; the fuel continues to leak after the closing of the injector – the injector is damaged and has to be replaced.


Note: of course, when MSD80 will identify, that in some cylinders the fuel is not burned, the engine management unit will turn off these cylinders. To perform the repeated test:

a) turn off/turn on the ignition (error message status of damaged cylinders will become passive);

b) delete the error messages;

c) repeat the test.


At the end – an excellent video from YouTube; Rolandas Latvys

As you can see, injector No.2 has a serious problem.


Related entries:

Cold engine and problems of injectors