How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask MB Paul Your Own Question
MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3567
Experience:  Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes
15777119
Type Your Mercedes Question Here...
MB Paul is online now
A new question is answered every 9 seconds

Car turns but won't crank. Changed crank position

Customer Question

Car turns but won't crank. Changed crank position sensor. Check engine light still on.
Submitted: 7 months ago.
Category: Mercedes
Expert:  Lou P. master tech replied 7 months ago.

Hello. First thing , does the fuel gauge show the correct level that you know of ?

Customer: replied 7 months ago.
I assume it does
Expert:  Lou P. master tech replied 7 months ago.

Wrong lol. We never assume. So a common occurrence is a failed rear Sam. The rear Sam controls the fuel pump and also the fuel level sensor so that is always a dead give away. Check for fuel at the fuel pressure test port.

Expert:  Lou P. master tech replied 7 months ago.

We need to know if we are missing fuel or spark.

Customer: replied 7 months ago.
Where is the test port located
Expert:  Lou P. master tech replied 7 months ago.

Right front of engine (passenger side )

Expert:  Lou P. master tech replied 7 months ago.

Pull the air cleaner up and follow the fuel rail to the front you will see the tire valve cap. Looks just like a tire cap. See if fuel sprays out. Then crank again and see if fuel sprays out again.