CDI cranks too many times before starting
 

2005 E320 CDI, with 116,000 km.

I do not drive the car often (once a week or so!); this has been since I owned the car, which goes back eight years. The drives are usually short distance (2-4 km).

Lately, the car cranks too many times before staring.

If I go for long drives, then it starts normally (i.e., after 3-4 cranks), regardless whether it is the same day or next day, when the car is cold.

There are no error codes.

The fuel filter was changed less than 2500 km ago.

Any hint int what may cause the issue would be appreciated .

Regards,
Farid

Check your Injector rail for voltage drops or a bad ground to each injector. Most German cars including VW & Audi use millivolts to the injectors and the wires can get broke or old and voltage will not go thru with change in temperatures and dampness. You could also have a bad glowplug or a bad glowplug relay sticking. Same thing with age, and dampness. I feel your injectors should be OK if it starts but not enough info on smoke coming out of tailpipe when starting. (amount, color)

Thank you Toldotom for your input.

If your diagnosis is correct, then why the drop in voltage would surface itself ONLY IF and WHEN I take the car for several short rides (rides less than 2 kms).

I emphasize it again, it never cranks more than two or three times if the car has been taken for a relatively long ride (more than 3 km), no matter how long I leave the car before I start it up again. This is my dilemma!

You need your glow plugs for helping to start the Engine when cold! Once the block of the engine is hot the Glow plugs might come on but the engine turns over quite Rapidly and the compression ignites the fuel. In most diesels the glow plug light comes on in the Instrument Cluster to show glow plug system is engaged but there is a Heat sensor of Engine Temperature to signal to turn them on for given time if needed. When your car is just barely warm the glow plugs probably are not on LONG enough to help the cylinders ignite and start the car. Thus, you flood the engine and it keeps cranking and you will have a NO START situation. The injector rail or connection will expand with heat opening the circuit! And either NO Fuel or too much!