Car will not start until I bang on the engine!

My car starts intermitermently. To get it started, I must bang on the engine with my tire iron. After several bangs, It usually starts but for the past 2 weeks, the banging is less effective. An auto machanic I saw told me that he had no idea what the problem was. Can anyone out there please help solve this mystery??? Thanks

Does not start needs clarification. It cranks, but will not start, it does not crank until I hit it etc would be helpful.

I believe you have a starter problem. The starter bendix can hang in the engine which will prevent it from turning the engine over. Banging directly on the starter will dislodge it and it will start. I see this all the time on the Ford Rangers. You need a new starter if this is what’s happening.

Sorry not clear. When I try to start my car, it does not always start. When it fails to start, it fails to crank. When it fails to start, I begin to bang on the engine. Then I return to the cab and begin turning the ignition key to start the car. When this fails to start the car, I begin the process all over again. Lately, this process has been getting drawn out.

Step one is to clean the battery connections, ground connection and cable connections to solenoid and or starter. Is it related to the engine being hot or cold?

You probably need a new starter as was said above. Bang directly on the starter in the meantime instead of the engine; you’ll probably have better luck.

I too agree with the starter assembly. Yours is a common symptom of fried contacts in the bedix assembly. Or perhaps even a worn and sticking assembly itself.

Here’s what happens. When you turn the key to “start”, a solenoid pulls a lever that’s part of the Bendix assembly. The lever slides the starter motor gear into engagement with the ring gear on the flywheel and also engages two contacts that complete the circuit to the motor windings. These contacts arc every time they’re engaged and disengaged, and they can get fried (contact material erosion and carbon desposition) over the years. The solenoid/level assembly itself can also wear and get sticky.