question for stevebfl and other like gurus
 

E500 is at MB dealer today Symptoms - difficult cold start. When starts, emits a rotten eggs odor and displays an intermittant rough idle. Dealer replaced plugs, caps and rotors on first try last week because advise a 56 code. I delivered it yesterday and they asked to keep it overnight to get DTC on a cold start.

My non coded nose tells me to replace the O2 sensor near the cats. What say you all?

TIA

Tom

O2 sensors aren't doing anything on a cold start, mixture is set by the temp sensor for the injection system, I'd have that checked out first.
Gilly

Thank You Gilly!
 

Intake sensor it was.

Tom

For any researching 500E E500 M119 Engine symptoms similar to above, before taking it to a dealer, you may want to replace the intake sensor P/N 009 542 68 17 first to see if it resolves problem.
The dealership replaced my caps, rotors and plugs on first visit on above symptoms to the tune of $800.00 The sensor is a $13.84 part that took the same dealership $141.36 in diagnosis and labor to get it right the second time.

Glad it lead to a good repair, to be honest I was referring to the coolant temp sensor.
Gilly

You know Gilly, I think those techs at the dealership would have replaced my wife if they thought it would fix the car and get it out of their shop. At one point it was pulling up enough codes to deplete thier parts department of M119 fuel management components.

I suggested, through the Service Advisor, that they replace the sensor without qualification as to which one. The tech recommended that the dealer keep the car overnight to test cold start in the AM. Reported "PERFECT" and I picked up the car.

Do you think that the above was just a "bandaid" and that the problem will reappear?

Tom