2002 ML500, ignition switch "spring return" from start position problem - PeachParts Mercedes-Benz Forum

Bigdaddybenz · #1 09-20-2011, 10:36 AM

Hi guys!!!

I'm sorry to have not had better words to concisely describe the problem that I am experiencing in "The Title" of this thread, so allow me to explain

I have a 2002 W163 ML500 with 177,000 miles.....When I attempt to start it the key feels like it is hanging up in the start position, and if I let it go it will continue to engage the starter without "spring returning" to position 2.

If I manually flip the key back to position 2 (run position)...the engine fires flawlessly and the vehicle operates normally.

Now, I know that many on here will suggest by default that I replace my Crankshaft Position Sensor......I replaced it less that a year ago.....

***On another note: (When I removed the defective CPS I was startled because it had a metal flake stuck to the magnetic pickup tip of the CPS, which I assumed was causing the problem......I immediately thought to myself that the starter drive gear must be meshing too tight against the flywheel ring gear, so I accessed the area under the bell housing, blew out any possible additional metal flakes, and then spayed white lube around the ring gear, while barring the engine over) <---Just thought I'd throw that in there in case some of you run into this....

Back to the subject at hand.....My question is: Does the "spring return tension from the key-switch start position to position 2" come from the lock assembly or is it built into the the actual ignition switch????

At this point, I'm assuming, and partially praying that it is inherent in the ignition switch's design.....So, I figure it can't hurt to change the ignition switch prior to getting into far more complex mechanical lock and tumbler issues....

Is there an exact procedure for replacing the ignition switch???......My concern is working around the driver's steering wheel airbag.....

Thanks in advance, as always for any replies

Dee

Bigdaddybenz · #2 09-20-2011, 03:45 PM

Think I was waaaaaaaaaaaaaay off the mark.......This vehicle is not getting SPARK during the cranking process.......When I flip the key back to the run position (position 2) quickly the vehicle starts every time......

So, my question is: What authorizes the coils to become "hot" during the cranking process, and what failure may I need to look for????

Thanks in advance

Bigdaddybenz · #3 09-22-2011, 11:09 AM

UPDATE:....OK, I AM COMPLETELY FLABBERGASTED!!!,,,,,I STOPPED AT THE STORE, CAME BACK OUTSIDE, CAR WOULDN'T EVEN CRANK.....

ANTICIPATING THE NEED FOR A FLATBED TOW TRUCK, I DECIDED TO ROLL THE CAR BACKWARDS INTO A MORE EASILY ACCESSIBLE POSITION......WHILE DOING SO, MANUALLY TURNED THE STEERING WHEEL AND PUT IT IN NEUTRAL

DECIDED TO ATTEMPT TO START THE CAR. JUST OUT OF SHEER BOREDOM WHILE AWAITING THE TOW TRUCK.....AND BAM!!!......NOT ONLY DOES IT SUDDENLY START, IT STARTS PERFECTLY AND THE INITIALLY ISSUE AS POSTED ABOVE IS RESOLVED!!!

SERIOUSLY GUYS, WTF JUST HAPPENED??????

NOW MY MIND IS REALLY FRIED!!!!

DID PUSHING THE VEHICLE OR MANUALLY TURNING THE STEERING WHEEL EFFECT SOMETHING THAT WAS OFF KILTER????

PLEASE HELP......THIS IS GOING TO BUG ME UNTIL THEY DAY I DIE!!!!

Bigdaddybenz · #4 10-01-2011, 09:29 PM

OK GUYS!!!!...........I REALLY, REALLY, REALLY, REALLY FEEL STUPID!

THE PROBLEM REOCCURRED, I DID LOTS OF DIGGING FOR INFO.....

BOTTOM LINE, IT WAS THE FUEL FILTER

W163 FUEL FILTER HAS A CHECK VALVE AND REGULATOR INCORPORATED INTO ITS DESIGN....MY CHECK VALVE WAS DEFECTIVE, THUS THE FUEL PRESSURE WOULD BLEED DOWN UPON THE VEHICLE BEING PARKED, AND IT WOULD TAKE THE ADDITIONAL CRANKING TIME FOR THE FUEL PRESSURE TO BUILD BACK UP!!!

YUP, I'M AN IDIOT!!!......BUT A LESSON WELL LEARNED, NEVERTHELESS! :-)

thnax, Dee!