Why the ##&&$&**@@ won't you start!

My youngest son inherited an 89 BMW 325i from his older brother. The problem he is having is that when he goes to start it, it just clicks when he turns the key. It will start right up if it’s jumped from another car. Thought it was a bad battery so put a new one in the 89 and it still just clicks, but again will fire right up when jumped from another car or using one of those handy emergency battery starters. Looking for some ideas as to why this might be happening.

Disconnect and scrape, with a knife, file, or sandpaper, the battery cable loops (inside) and the battery posts. The large and small cable attaching to the starter may not be making good ELECTRICAL contact, either.

Sounds like the starter is reaching it’s end of life, replace it.

I also suspect a bad connection, either at the battery or at the other end of the ground cable from the negative battery terminal (or the ground strap from the engine to the chassis). Where was the negative jumper cable connected when it was successfully jump started (negative terminal, or someplace on the engine)? Just for fun, try running a jumper cable from the negative battery terminal to a good ground location on the engine and try starting it.

Really doubt it’s the starter since it will start when it’s jumped by another car. If the starter was bad then jumping would have no effect.

Sounds like the battery cables need cleaning or even replacing.

I like your idea. The car has the battery in the trunk and a jumper post under the hood. When you jump it, you need to ground it to the block. This would take the battery’s ground cable out of the picture. My son and I will have to trace the ground circuit to see what we find.

That’s what I’m thinking also. It could be a bad grounding cable because the battery is in the trunk and the jumper post is under the hood. When we jump it, we need to ground it to the engine block so the problem could be between the battery and where it’s grounded.

I would have to agree with Ed. I think it is the starter also. But of course you should check all battery connections before going to the starter. After checking your connections remove the starter and take it to one of your local auto part store and have them test your starter.

Found out the problem, assumed my son knew what “connected to the battery terminals” was. Turns out he had not tightened the cables to the battery. Solved his problem, he thought I was a genius. Now it’s on to the horn and back-up lights

Thanks for the feedback response. Glad it was positive. Now, if more people would try this “communications” type of approach to problem solving…THAT could go a long way towards actually solving their problem!