Start problem may be simple as loose connection

Dear Car Talk:

Our 2007 Mazda CX-7 recently had its steering pump lock up and burned out the belt. The belt and pump were replaced, but a week later, the car is starting strangely: When we turn the key, there is a loud and fast clicking sound from the driver’s side under the hood, and the engine doesn’t even attempt to turn over. After a few tries (about 25 seconds’ worth sometimes), the starter will engage, turn over the engine, and the car starts right up. However, while we drive, various warning lights flicker on and off, like the traction-control system and air-bag lights. What is happening that causes the clicking sound? Is it the starter solenoid failing to actuate the starter motor? Or is it something in the electrical system, and my mechanic didn’t do a thorough enough check?

-- Benjamin

When you hear a rapid clicking noise, Benjamin, it’s usually because the starter motor isn’t getting enough current from the battery. You’re hearing the starter motor’s solenoid trying to engage but failing to.

So, it could be a failing battery; it could be a bad alternator that isn’t properly recharging the battery; or it could be something as simple as a bad connection at the battery. You need to take it back to these guys and have them do a complete test of your charging system. That would include testing the alternator output and load-testing the battery.

Could it be related to steering pump failure? It’s possible. If the belt got really chewed up, some debris could have gotten into the alternator and caused it to fail. But it also could be coincidence. If the battery is on the edge of failing, that could just be due to old age.

Or the whole thing could be explained by your mechanic’s failure to tighten the battery terminal. If he removed the negative terminal from the battery to disconnect the power before doing the repair, and then forgot to retighten it, that would explain everything.

A loose connection would explain why the starter can’t get enough juice sometimes, but then eventually starts right up. It would explain why lights on your dashboard are coming on and off -- as you drive around, the terminal clamp jostles around as you go over bumps.

And best of all, it would cost nothing to fix. Unless you count the price of embarrassment that your mechanic will experience. So ask him to check that first, Benjamin.

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