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MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4317
Experience:  Mercedes Benz Qualified Diagnostic Technician
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I am having problems with my a190 amg-ignition failure after

Customer Question

I am having problems with my a190 amg-ignition failure after being parked for a few hours.Generally starts in the morning. Have had diagnostic test x2 by garage (not a mercedes garage unfortunately) to find problem.A mystery. Bought car last july from a friend and he ommitted to tell me that this had happened several times before.Am guessing not the starter motor as car would be obsolete by now.Help....
Submitted: 3 years ago.
Category: Mercedes
Expert:  MB Paul replied 3 years ago.
Hi,

could you tell me more about what is happening please:

Does the ignition come on when you turn the key?

If so does the car crank over and not start or does the engine not crank over at all?

Are you getting any warning messages on the dash?

Best regards, Paul
Customer: replied 3 years ago.

Hi,


When it does start it can crank over and stop mid spark.On occasions that it refuses to start it omits a low (excuse the description) "ugh" and no spark or any intention of sparking. Starts when I leave overnight.One method I had been using which appeared to work until last couple of days,was taking key to half way point,pumping the gas then cranking the key fully in the barrel.Now that isnt working.Am wondering ignition connection? Thanks for your help.

Customer: replied 3 years ago.

No warning messages on dash.

Expert:  MB Paul replied 3 years ago.
Hi,

If the engine is cranking over then it sounds likes the starter motor is ok.

I assume the car has been checked for fault codes on a diagnostic tool with no faults stored?

If so then a possible cause is a bad crankshaft sensor - this can cause issues like you have described without storing any fault codes. It is fairly cheap & easy to replace.

another issue we see on the A Class is with fuel pressure problems - usually caused either by a faulty fuel filter or a bad fuel pump. A fuel pressure test with a mechanical test gauge would be a good idea at this stage to see what the pressure is actually reading.

Best regards, Paul
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Customer: replied 3 years ago.

Have booked in for full diagnostic with mercedes garage next week.Thanks for your help.

Expert:  MB Paul replied 3 years ago.
Hi,

no problem at all. I hope all goes well & let me know if you need anything else

best regards, Paul

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