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Q: Car cranks but won't start - 2007 Mercedez-Benz E350

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Car will crank but wont start. If it starts it runs great as long as you dont turn engine off. When it gets hot it needs 24 hrs before if will start again. I have changed spark plugs, cam sensor, crank positioning sensor, fuel pumps, new gas cap and all fuel injectors also intake manifold. Nothing has changed. It still cranks but engine wont turn over. Once started it runs until you turn engine off. Then you have to wAit FOR cool down before it will restart. Help!!!

My car has 115000 miles.
My car has an automatic transmission.

A: Hello. There are quite a few things that ca...

Hello. There are quite a few things that can cause this. It appears that you have already changed quite a few parts trying to overcome this problem. From what you are explaining, this is almost always fuel related. I have had a lot of these vehicles act up like this and the problem is usually with the fuel pump relay or with the relay connections in the fuse box. The only way to find the problem is to see if the engine is lacking fuel or spark when the problem occurs.

Most of the time it will be because the fuel pump is not coming on. At that time, the circuit can be tested. The excessive heat typically causes a bad connection. If you are thinking of having this starting issue checked, consider having a certified mechanic, such as one from YourMechanic, who can come to your home or office to diagnose why it will not start.

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