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98 BMW won't start sometimes-intermittent problem

My 98 BMW 528i with 90,000 miles will not start every time. Been properly maintained since new. Typical is that it starts in the morning, I go to the first stop, it won’t restart. Hear clicking noise like bad battery and the dash lights flash. Usually requires jump or Booster Pak to restart. Sometimes (not all) it will restart without help after a few (15) minute wait. New battery 2 months ago. My BMW trained mechanic, not a dealer, has checked battery, it is good. Also checked alternator and said it puts out 14 volts (I’m told above 13 means it is OK). We are both at a loss. A quick charge on the battery lasts about one week. Any thoughts?

My conclusion is your new battery is “bad”.

Or perhaps you have a loose connection or corrosion at the battery, jump point under the hood, starter, or one of the grounds. Check and clean 'em all.

Any reputable parts place will check your battery free of cost. If it’s free of any charge, they will have to charge the battery so they can check it.

As MG suggest and I would add, be sure to check both ends of every cable involved.

Thanks. We retested the battery and it is good.

We checked the connections and they all appear OK. When testing the battery while off the car, it holds the charge. However, when in the car, it slowly drains. Our conclusion is something in the system is “on” and draining the battery when the car is not running. So, I guess we go to the dealer and put it on the scope next. Any oter thoughts?

How did the parasitic draw test end up? My conclusion when you say “will not start” is you are experiencing slow or no cranking.

When the engine fails to crank what is the status of the batterys charge?

When I say “will not start” I hear clicking noise like bad battery and the dash lights flash. It will not turn over. Requires jump or Booster Pak to restart because the battery has been drained. To test the battery, we removed the battery from the car and it held the charge when tested. Placed it back in car and the gauge shows something is draining the battery slowly. The new battery is a Bosch battery. Dealer says I need a BMW battery because they hold a stronger charge longer to handle all the computer stuff they placed in the car. After they place a BMW battery in the car they can run the diagnosis to determine what is draining the battery. This is what I fear about the dealers. Any thoughts? And thanks for the help.

The scenario is as follows, You turn key to start,all you hear is “clicking” you remove battery for test,you don’t say what the state of batterys charge,you just say it “held the charge” if I interpet correctly you are saying a battery that load tested good will not crank the engine.

Then your thread dives into a battery drain area. It takes time (dependant on how large the drain)to destroy a batterys ability to crank the engine adaquately,it does not happen immediatly.

A battery that load tests good should crank the engine (unless you killed it by the load test,unlikely)The drain issue is a longer term issue.

Give me the results of what happens when you take a fully charged battery,install it in the car and IMMEDIATLY try to crank the engine.Try cranking ten times until it starts over a 5 min period, it should start every time (it should start many more times than this,but WE will start here)

You don’t need to use a BMW battery.

Well, here’s what I hope is the final resolution. The BMW dealer kept the car 8 days, checking all systems on their computer, starting, restarting, etc. After they replaced the new Bosch battery with a BMW battery, the problem disappeared. They told me to use the car as normal, and report back if it did not start again. To date, it has started every time. It appears the new Bosch battery was bad. Of course, my regular mechanic says you never know if in their testing they adjusted something or hooked up something that was the real problem. For now, I’m happy.

Thanks to all who tried to help.

I was the first to respond to your post and what did I tell you? new battery bad