Hello everyone, I have a 07 E350 4Matic with 50k on it. I have started to encounter problems with starting my car. This happens once in awhile, and not all the time. I would crank the car over to start and it would start but then shutoff. Sometimes the car would just keep cranking and not even turn over. But on most days, the car starts up normal.

I don't know if it has to do anything with gas, but just the other day I was low on fuel and I parked the car on a steep hill. The car wouldn't turn over, So I called my brother to bring over some gas and he brought a 1 gallon tank of 87. I poured 1 gallon of the 87 in the tank, just enough to make it to the closes gas station and I filled the entire tank with 93 octane like I always do. I noticed a change in performance, but after I burned the entire tank out and refilled another 93 in the car, it ran beautifully again.

But then, I started to have problems with the car turning over. So, I brought my car to my local MB dealer for service, I explained to them my situation and they ran a diagnostic test on the car, they said there was nothing they could find, and if it happens again, bring the car back. Well, the next day I brought the car home, it happened again. So now im thinking maybe the 87 gas that I poured in fouled my spark plugs? Ether that, or my fuel pump is starting to go?

By the way, there are no lights or messages on my dash when this problem occurs. And I also noticed, if I turn the key and wait 5 seconds or more the car will start perfectly normal without stalling or dyeing. But if I turn the key quickly, the car just stumbles and dies once in a while. Please, any suggestions or thoughts to help me out would be kindly appreciated! Thanks.

 

Im amazed with all these views and no tech answers.

 

Well,

It is not 100 % clear from your post that if the car cranks or not each time you try to start it.

But, when it starts and then shuts off it sounds like it could be a fuel pump issue. Also, the statement that if you wait between turning the key ON and turning it to crank makes it to start better also speaks about fuel pump issue.

When you turn the key ON but don't crank it you should hear the fuel pump come on for a second or so. If you don't hear this the pump does not work correctly.

It could also be a fuel pressure regulator problem. Pressure regulator is at the other end of the fuel rail after all injectors and lets excessive fuel back to the fuel tank. If this regulator goes bad, i.e. loses its spring, as they so many times do when they get old, the fuel spraying would not work correctly with inadequate pressure at the fuel injectors.

 

Hey, you're in the wrong forum , your car is W211 but this place is W212 . Mods need to move this thread to a proper place so that you can get tech replies from experts

 

All the tech experts for your car are in the W211 AMG forum...search first, then ask.

 

Took it to the dealer, they found that the crank position sensor is damaged from over heating. Thats what caused the car to not fire up.

 

I presumed crank sensors would cause stalling issues only . Thanks for your feedback , happy safe driving

 

Dealer called me back after they finished installing the new crank sensor, they said the car starts up like new, but now the car runs rough. They said my fuel pump is done, and needs to be replaced. They said its 1,050 parts and labor to get that fix. And they said that I have engine oil leaking from a ripped head gasket. I don't know if there pulling my leg, because the car never ran rough with me. It just had that hard starting problem. Is my local dealer pulling my leg or what?