Searched around on the forums and noticed a lot of owners have had to replace the injectors. Spoke with MB mechanic to get an estimate on what it would cost to have the injectors replaced and he mentioned that he hasn't had to replace any on 300 SDL and asked why I felt that I needed to have them done. I explained the symptoms smoke especially when accelerating, loss of power, hard start, and finally now the car does not start at all. He said that it could possibly be the fuel pump.

My question is has anyone had a similar issue with an SDL? I am willing to replace the injectors with new Bosch (don't have enough time to rebuild with Bosio or Monarch parts and can't find anyone near me to run pop test to ensure good spray pattern.) How can I confirm if the the pump needs to be replaced? Not noticing any leaks in the garage or around the engine which is why I suspect injectors.

The injectors won't prevent a start.

You problem is most likely related to fuel filters, primary and secondary, and/or the tank screen.

After those are changed or verified, then you can check the output from the pump.

Thank you Brian. I will check filters over the weekend and report back.

With any suspected fuel issue change the fuel filters with known good ones first. Can save dollars and agrivation to have some and the tools to change them always in the trunk. It may not be the filters but you have to know it is not unless something else is patently obvious.

This pretty well applies to all diesels. Do not fuel at small low volume places either. Larger truck stops tend to be much safer. I have never got truly bad fuel from one. If not self service make sure the attendant is really putting diesel fuel in.

Finally got around to looking at the car. Turns out the problem was a combination of the battery terminals needing to be cleaned and a weak battery. Once they were cleaned and car jumped, started up fine.

This thread is a perfect example of how an inaccurate description of the symptom(s) can lead both the owner of the vehicle and the entire forum down the wrong path.

The actual symptom, but never stated, was "slow cranking speed".

All of the other symptoms, while possibly present to a small degree, were not relevant to the problem and had nothing to do with the solution.

Glad you got it resolved. I'm a bit curious what turned your mind away from the fuel filters and the pump (which you were hell bent on changing).

The car belongs to my mother and she never mentioned slow cranking, only the symptoms which I listed originally, which is why I never listed it as a symptom. I was confident that it was not both fuel filters because they had been changed in Sept 2011 when the car was in the shop for a fuel leak and power steering gear box replacement. In Oct 2011 a new battery had been installed and I assumed the shop that installed it had cleaned the terminals.

Yesterday when I tried jumping the car and it still would not start. My mom reminded me that we had the same problem years ago. When she mentioned that, I realized it was the terminals.

Fuel filters are not a time thing. One really dirty load of fuel can finish them. That's why anytime there is a suspected fuel issue either prove you have good fuel flow existing or change them.

There is no long term harm either as if the filter you pulled proves not to be the issue. just put it in a tight container and carry it as an emergency spare in the trunk.