suming

My 2008 e 550 has this problem which seems to be getting worse.

Recently it has started first thing in the morning with no problem. Recently once the car is warm it is hard to start. Cranks for a very long time over and over. Today the battery seemed to have died from cranking it so many times. The lights inside the car were dim and it turned over very slowly, then suddenly the engine came to life.
Have cleaned maf sensor, checked cps, spark plugs etc. Still happens. Sometimes it starts no problem but others it takes minutes of trying.

Any ideas? Could this just be a bad battery? Only code is misfire codes.

konigstiger

Replace crankshaft position sensor part # 6429050000 see attachments.

suming

Thank you bud! I'll do this today

suming

Scanned the car and had crank position sensor. Replaced it and still have the problem.

suming

Update: went to start it after driving for about 20 mins and no start. Tried cranking it over and after about 5 goes my battery completely died. Put a different fully charged battery and still no start. Now suspect it is the fuel pump. Any ideas?

rapidoxidation

Does it start when it gets a whiff of ether in the intake? If your fuel pump is an issue, it'll still start with ether but won't keep running.

konigstiger

CPS was one problem, next explore fuel pressure: http://www.mercedesmedic.com/fuel-sy...hooting-guide/

suming

Will check the fuel pressure and pump today. Funny thing was when checking codes last night after trying to get it to start the crank sensor code came up but it wasnt the open circuit code. No other codes or misfires