Is my starter motor dying? [UPDATE 11/2]

[atruelunatic]

For the past month I thought my car has been taking longer than usual to start. Think 2 seconds versus 1 second. Then today, I drove 90 miles and stopped my car. When I tried starting it after 10 minutes, it took a few seconds and now I can actually hear the engine cranking slowly until it finally catches.

I was hoping it'd be a one time thing, but doesn't look like it as it did it 3 more times today.

The first and second time I was under 1/8 of gas. The 3rd time I was at the gas station after I just filled up. The 4th time was after another 2 hour drive at home where I was able to record this video from the outside. I tried recording from the inside, but you can barely hear the car start so this outside video is a lot better.

I'm thinking the starter motor needs to be replaced, what do you guys think?

I just measured the battery voltage after the last 2 hour drive to be 12.3 V.

More info on car relating to the engine:
2011 e92 M3
90,600 miles
Rod bearings replaced at 89,300 miles with WPC coated and ARP bolts
Akra evo with ESS tune
Macht Schnell air filter
Below is the video:

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UPDATE 11/2: See post #17
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[Beemdog]

AGM batteries can lose the ability to produce cranking amps without a large drop in resting voltage. Typically you will see a large voltage drop when the starter is actually cranking over if the battery is tired. Can you have someone crank the car over while you monitor the battery voltage? When these AGM batteries decide to go, they can lose capacity very quickly, even if stored on a battery tender.

Another option is to start the car when jumped to an external battery via jumper cables and the underhood connections. If the starter cranks quickly/normally, then you know the starter is OK. Starter for an M3 is an expensive piece and difficult to get to compared to many other cars (it's buried under the throttle bodies in the Vee of the engine block), so I wouldn't change it unless you know it is going out.

[atruelunatic]

Originally Posted by Beemdog

AGM batteries can lose the ability to produce cranking amps without a large drop in resting voltage. Typically you will see a large voltage drop when the starter is actually cranking over if the battery is tired. Can you have someone crank the car over while you monitor the battery voltage? When these AGM batteries decide to go, they can lose capacity very quickly, even if stored on a battery tender.

Another option is to start the car when jumped to an external battery via jumper cables and the underhood connections. If the starter cranks quickly/normally, then you know the starter is OK. Starter for an M3 is an expensive piece and difficult to get to compared to many other cars (it's buried under the throttle bodies in the Vee of the engine block), so I wouldn't change it unless you know it is going out.

Thanks for your reply. That is what a shop I just sent this video to also said. We'll be doing a load test next week to double check.

I saw DIY instructions for the starter, and it looks too challenging for me as it is buried deep. I'm not confident yet to remove the plenum.

I'm a little confused about the underhood connections. Do you literally mean something to connect the external battery in the engine bay? I would have thought jump starting our M3s would be just to the battery in the trunk. If you can confirm, that'd be great. I don't have another battery, but do have another car to jump start off of... but not sure if that'll provide the correct amount of volts/amps necessary to start our cars.

Thanks again for your fast reply!

[Beemdog]

Originally Posted by atruelunatic

I'm a little confused about the underhood connections. Do you literally mean something to connect the external battery in the engine bay? I would have thought jump starting our M3s would be just to the battery in the trunk. If you can confirm, that'd be great. I don't have another battery, but do have another car to jump start off of... but not sure if that'll provide the correct amount of volts/amps necessary to start our cars.

Thanks again for your fast reply!

Yes, under the hood are the connections for jump starting your M3. There is a post on the passenger side fender for the negative ground (far left of engine compartment up high when standing in front of the open hood).
The positive terminal is under a red plastic cap toward the back of the engine compartment, also on the passenger side. There should be a pic in your owner's manual.

You can jump start the M3 from another car, but use care and make sure the cable clamps are really secure, since a poor connection will also crank slow. I also generally avoid jump starting from a smaller class of vehicle, such as a 4-cylinder economy car. Poor quality or small wire gauge jumpers will also produce a slow cranking starter. Sometimes it's best to go to a shop if you don't feel great about your jump starting setup (and you will hear of people botching this procedure up and damaging something).

[atruelunatic]

Originally Posted by Beemdog

Yes, under the hood are the connections for jump starting your M3. There is a post on the passenger side fender for the negative ground (far left of engine compartment up high when standing in front of the open hood).
The positive terminal is under a red plastic cap toward the back of the engine compartment, also on the passenger side. There should be a pic in your owner's manual.

You can jump start the M3 from another car, but use care and make sure the cable clamps are really secure, since a poor connection will also crank slow. I also generally avoid jump starting from a smaller class of vehicle, such as a 4-cylinder economy car. Poor quality or small wire gauge jumpers will also produce a slow cranking starter. Sometimes it's best to go to a shop if you don't feel great about your jump starting setup (and you will hear of people botching this procedure up and damaging something).

Ah! I know the red terminal you're referring to--always wondered what it was for. Thanks for the insight. The only car I have available is a 4 cylinder economy car haha, so I'll just have to wait until Monday to do a load test. I guess I should start looking into the Carly app for the new battery.

[BMRLVR]

Probably your battery. You should see 12.6-12.7 V when tested at the battery posts. Fully charge and then load test the battery, if it fails the load test, replace the battery.

[bimmer414]

Most auto parts stores will have a carbon pile load tester available to test the battery for free. I'd do that first.

[atruelunatic]

Originally Posted by bimmer414

Most auto parts stores will have a carbon pile load tester available to test the battery for free. I'd do that first.

Originally Posted by BMRLVR

Probably your battery. You should see 12.6-12.7 V when tested at the battery posts. Fully charge and then load test the battery, if it fails the load test, replace the battery.

Originally Posted by Beemdog

--

Hi all,

What I did today in the morning was drive my car to Autozone:

First crank was similar to video. Got to Autozone to have them test it, but find out someone stole their mobile battery tester so I went ahead and removed the battery (and closed the doors and trunk... thankfully the door didn't lock since the battery was out and was able to release the rear seats through the ski hole and pop the trunk).

They didn't let me use a new battery to jump start from the engine bay posts, but when we tested the battery it was at a 67%-70% charge, but still had "Good battery" displayed.

We let the machine charge it and it was able to charge up to 12.97 V (who knows the accuracy of these machines, but still) and was indicated as a "good battery".

I popped the battery back in the car and when I started the engine back up, all was fine and was able to get the car to crank easily out of their lot.

Got home (5 min drive) and tested with my cheapo multimeter to find that the voltage is 12.1~12.2 V.

The car is sitting outside right now, not sure what I should do at this point... maybe I should just get the battery anyways as a maintenance item.

What do you guys think is the culprit? I'll try starting the car again in about 3-4 hours.
1) Bad battery
2) Bad starter motor
3) Bad alternator

First two being the likely cause.

Worst case I see with buying a new battery is that I'll have a new battery, but will need to replace something deeper. Is it possible for the load tester to be wrong that the battery can't hold a charge?

[0_to_60]

If you are in Los Angeles, i have a nice load tester and can tell you if your battery is actually bad. Recently my battery was acting weird. It was holding voltage but dropping in ampage. I got hold of a used oe battery and did the same load test and did a side by side test and if you see the lightest drop in amps your battery is weak. Also noticed my old battery was charging to full pretty quick, compared to the used oe agm

[Beemdog]

There is another possibility in that you can have something on the car constantly drawing current from the battery even as it sits there in an "off" state. However, since the battery ran down just from driving home, it does seem that the car's alternator may not be charging properly. This is not a simple alternator circuit and charges only when it is told by the electronic control unit to do so. There should be a charging voltage of around 14.4V when the alternator is operating in charge mode. You may need to have your charging system analyzed by someone who is familiar with "smart" alternators.

[Malek@MRF]

More than likely your starter is dying. This is a more common issue among other BMW's as well.

[atruelunatic]

Originally Posted by Beemdog

There is another possibility in that you can have something on the car constantly drawing current from the battery even as it sits there in an "off" state.

I hope it's not this. I'm going to swap out the battery later today and drive for about 30 minutes and see what happens when I start the car later tonight.

Originally Posted by 0_to_60

If you are in Los Angeles, i have a nice load tester and can tell you if your battery is actually bad. Recently my battery was acting weird. It was holding voltage but dropping in ampage. I got hold of a used oe battery and did the same load test and did a side by side test and if you see the lightest drop in amps your battery is weak. Also noticed my old battery was charging to full pretty quick, compared to the used oe agm

Thanks man. I was just in LA yesterday, should have posted while still out there haha. I'm going to go ahead and just swap the battery and see where this takes me for the time being.

Originally Posted by Malek@MRF

More than likely your starter is dying. This is a more common issue among other BMW's as well.

Thanks Malek for the insight. I hope it really isn't dying though, BMW buried the starter deep in there! I'm going to swap out the battery first and see where this leaves me. Thank you for your help via e-mail as well.

[Malek@MRF]

Originally Posted by atruelunatic

I hope it's not this. I'm going to swap out the battery later today and drive for about 30 minutes and see what happens when I start the car later tonight.



Thanks man. I was just in LA yesterday, should have posted while still out there haha. I'm going to go ahead and just swap the battery and see where this takes me for the time being.



Thanks Malek for the insight. I hope it really isn't dying though, BMW buried the starter deep in there! I'm going to swap out the battery first and see where this leaves me. Thank you for your help via e-mail as well.

I have a couple new AGM BMW batteries I have here for testing. Why don't you swing by and have the battery tested and try a new battery before buying a new one and eliminate all guess work.

[WickedE93]

Originally Posted by Malek@MRF

I have a couple new AGM BMW batteries I have here for testing. Why don't you swing by and have the battery tested and try a new battery before buying a new one and eliminate all guess work.

Malek is so cool! Who does that?! He does! You should definitely take him up on his offer OP, he's a good guy and knows these cars inside and out.

[BMRLVR]

Originally Posted by Malek@MRF

I have a couple new AGM BMW batteries I have here for testing. Why don't you swing by and have the battery tested and try a new battery before buying a new one and eliminate all guess work.

Great offer!

[atruelunatic]

Originally Posted by Malek@MRF

I have a couple new AGM BMW batteries I have here for testing. Why don't you swing by and have the battery tested and try a new battery before buying a new one and eliminate all guess work.

Hi Malek,

I really wish I could, but the 3 hour drive out there kills and I don't think I'll be in the area for a long while. Awesome offer though.
Thanks!

Originally Posted by WickedE93

Malek is so cool! Who does that?! He does! You should definitely take him up on his offer OP, he's a good guy and knows these cars inside and out.

He is for sure! He swapped out my rod bearings not too long ago as well. It's just the drive out from Ventura that kills. I was just in Irvine yesterday though which I should have called Malek while in the area and try a diagnosis on the phone. But with rush hour slowly starting, I only thought about one thing: get home ASAP.

[atruelunatic]

Update 11/02/2015:

Over the weekend I replaced my battery as this was the first culprit I think and some good news... The car starts up more reliably! When I first installed the battery, the problem didn't go away, but I at first attributed it to the battery not being fully charged off the shelf. After about 1 hours worth of cumulative driving, the car starts up every time within a few seconds and is consistent now.

Now this may be in my head, but I think it still takes a little bit longer than usual. What do you guys think?

All clips are about 5-10 minutes apart. Car being already at proper temp.

I had errands to do and they were all within 5 minutes of one another, car was pretty warm so not as bad as a cold start. I'll continue to record the starter sounds until I feel 100% confident the problem is solved, but still wanna hear what you guys think... normal?

Please excuse the watermark, didn't have anything readily available haha

[bimmer414]

Seems like it's struggling a bit. Mine turns over faster

[Malek@MRF]

Originally Posted by atruelunatic

Update 11/02/2015:

Over the weekend I replaced my battery as this was the first culprit I think and some good news... The car starts up more reliably! When I first installed the battery, the problem didn't go away, but I at first attributed it to the battery not being fully charged off the shelf. After about 1 hours worth of cumulative driving, the car starts up every time within a few seconds and is consistent now.

Now this may be in my head, but I think it still takes a little bit longer than usual. What do you guys think?

All clips are about 5-10 minutes apart. Car being already at proper temp.

I had errands to do and they were all within 5 minutes of one another, car was pretty warm so not as bad as a cold start. I'll continue to record the starter sounds until I feel 100% confident the problem is solved, but still wanna hear what you guys think... normal?

Please excuse the watermark, didn't have anything readily available haha

Your starter is on it's way out. This is not a rare problem among modern BMW's.

[pbonsalb]

Because the starter is in the V of the V8 or because of the 12:1 compression or because BMW is not specifying high quality starters from its suppliers?