My 2008 E350 Mercedes-Benz recently gave me a major headache with a frustrating starting problem. One day, it just wouldn’t start. The engine would crank, but it refused to turn over. After some troubleshooting and a few parts replacements, we finally figured out the issue, and I wanted to share my experience in case it helps anyone else experiencing similar problems with their 2008 E350.
Initially, suspecting a common culprit, we replaced the crankshaft position sensor. After this, the car started and ran for a few hours. Relieved, I thought the problem was solved. However, after a quick stop at the store, the dreaded no-start condition returned. The engine cranked strongly, but wouldn’t fire up. Interestingly, after letting the car cool down completely for about 5-6 hours, it would start again. This was perplexing. I managed to drive it straight to my trusted mechanic, hoping for a more permanent solution.
The next day, with the engine cold again, my mechanic confirmed the issue – the car wouldn’t start. His first step was to check the fuel pressure, and it was reading zero. This pointed towards a fuel delivery problem. Based on this, we decided to replace the entire fuel pump assembly. After the fuel pump replacement, my 2008 E350 ran perfectly for three days. I was thrilled, thinking the ordeal was finally over.
Unfortunately, on the fourth day, the problem resurfaced, even more dramatically. While driving on the highway, the car suddenly stalled on the off-ramp. Thankfully, I was able to coast to the side of the road. This time, however, the car wouldn’t restart, even after cooling down completely. It was towed back home, and I was back to square one.
My mechanic revisited the car and again checked the fuel pressure. Just like before, it was reading zero. This led him to suspect a different issue – a faulty fuel sending unit. He hypothesized that the sending unit might be incorrectly reporting the fuel level, leading the car to believe it was out of fuel even when it wasn’t. To test this theory, we added 5 gallons of gasoline to the tank, even though the gauge indicated there was fuel.
And that was it! The 2008 E350 Mercedes started immediately and has been running flawlessly ever since. It turns out that the fuel sending unit was indeed the problem, causing inaccurate fuel level readings and leading to fuel starvation. If you’re experiencing similar starting issues with your 2008 E350 Mercedes, especially if you’ve already checked common components like the crankshaft sensor and fuel pump, consider investigating the fuel sending unit. Adding a bit of fuel to see if it starts might be a simple diagnostic step to point you in the right direction.
