[Cge92]

Hey all,

Recently ran into an issue with my 2008 335i. I had the car parked for over a week, went to start it and got nothing but a "click" I figured the battery was weak as it was a few years old, no big deal. Jump started from the terminasl under the hood and got it started. Drove to autozone, and picked up an H7 battery and installed it. Voila! Car started up no problem. Drove it around for the remainder of the night with no issues, until the end of the night. Car was doing the same thing, just getting a click when i went to start it. I was on a slight decline so i went to pop start the car like an old dirt bike, but didnt have enough speed so the car just stopped. I went to try to start it again, and it started.

At this point in time, i figured it must be the starter. I buy a starter online. Once it arrives, i bench test it, and it works perfectly. I installed the starter, and once i got the car back together, i was having the exact same issue. If i jump start it off of the terminals, car starts no problem. I check voltage at the battery and its just over 12v. Next i check voltage at the alternator and get over 14 at low idle. I drive back to autozone, replace the battery thinking the one i got could potentially be faulty. I load test the new battery before installing, and same problem. Just a "click", but the engine will not turn over. Next i disconnect the IBS from the battery thinking that could be it, but nothing.

At this point in time, im pretty confused as to what it could be. My thoughts are a loose connection somewhere between the battery and the starter? Anyone ever experience anything like this before? I did a thorough search, but couldnt find much.

Thank you to anyone in advance who can help me out!

Chris

[Bavarian Tech]

Did you check the ground strap ?
Is the battery cable from the Jump start post to the starter/alternator tight ?
Is the battery properly connected at power distribution box ?

[BeastMode335i]

Since you put in a new starter I'd say it sounds like a bad ground...

There's a braided cable on the rear left side of the engine that goes to the frame below the drivers feet area that is known to rot and cause these issues..

[BeastMode335i]

Originally Posted by Bavarian Tech

Did you check the ground strap ?

^^^ x2

[nissubaru]

I'm a little confused on the order of events leading up to your post. Have you been having to jump the car every time? It sounds like you jumped it once when you found the battery dead, went to AutoZone for a replacement, swapped it in. Car started up just fine but after a day or so of driving it wouldn't start again? At this point you went ahead and installed a new starter and then the car wouldn't start. You then somehow went back to AutoZone (did you jump the car?) and got another new battery, which now supposedly doesn't work at all?

What's confusing me is at which point are you able to start the car and at which point are you stuck jumping it with the under hood connections? After replacing the battery the first time you said the car started up just fine, then you replace the battery AGAIN with another new, good battery, and now it doesn't start at all? If that's truly what you're saying then I would be inclined to look into the E90 power cable recall to see if the symptoms match up with what you're seeing

https://www-odi.nhtsa.dot.gov/acms/c...3V044-6848.PDF

If the car starts fine with a healthy battery then I would definitely look into your ground strap on the drivers side as others have already mentioned. In my opinion you don't have to jack the car to see if the wire is all shitty and green, you can get a good idea by using a multimeter . I would do this by trying a few different ground points on your negative lead on the multimeter:

1. Start with your positive lead on the positive cable connected to the alternator. Ground the negative lead on the alternator housing or wherever you were seeing the 14V at idle. This should be your best reading and if your alternator isn't outputting 14V when grounded to the block or the alternator itself, then your alternator is bad. That doesn't seem to be the case here though.
2. Take another measurement using the same positive cable on the alternator, but this time use a non-engine block piece of metal as your ground. I like the strut bolts since it's part of the body. If your ground was shitty like mine then you might get a reading like 13.5V here, which as you can probably tell is a .5V drop (not good)
3. This is probably the ultimate test, but with the car still running go to the back where the battery is and take a reading using the usual positive and negative terminals of the battery (ground on the negative). If your reading comes out significantly less than the reading at the alternator, then you probably have a grounding issue. Also, the numbers I used above are just for reference, the numbers you see may be different, point is you're looking for these values to drop as you make your way towards the battery.

[Cge92]

Originally Posted by nissubaru

I'm a little confused on the order of events leading up to your post. Have you been having to jump the car every time? It sounds like you jumped it once when you found the battery dead, went to AutoZone for a replacement, swapped it in. Car started up just fine but after a day or so of driving it wouldn't start again? At this point you went ahead and installed a new starter and then the car wouldn't start. You then somehow went back to AutoZone (did you jump the car?) and got another new battery, which now supposedly doesn't work at all?

What's confusing me is at which point are you able to start the car and at which point are you stuck jumping it with the under hood connections? After replacing the battery the first time you said the car started up just fine, then you replace the battery AGAIN with another new, good battery, and now it doesn't start at all? If that's truly what you're saying then I would be inclined to look into the E90 power cable recall to see if the symptoms match up with what you're seeing

https://www-odi.nhtsa.dot.gov/acms/c...3V044-6848.PDF

If the car starts fine with a healthy battery then I would definitely look into your ground strap on the drivers side as others have already mentioned. In my opinion you don't have to jack the car to see if the wire is all shitty and green, you can get a good idea by using a multimeter . I would do this by trying a few different ground points on your negative lead on the multimeter:

1. Start with your positive lead on the positive cable connected to the alternator. Ground the negative lead on the alternator housing or wherever you were seeing the 14V at idle. This should be your best reading and if your alternator isn't outputting 14V when grounded to the block or the alternator itself, then your alternator is bad. That doesn't seem to be the case here though.
2. Take another measurement using the same positive cable on the alternator, but this time use a non-engine block piece of metal as your ground. I like the strut bolts since it's part of the body. If your ground was shitty like mine then you might get a reading like 13.5V here, which as you can probably tell is a .5V drop (not good)
3. This is probably the ultimate test, but with the car still running go to the back where the battery is and take a reading using the usual positive and negative terminals of the battery (ground on the negative). If your reading comes out significantly less than the reading at the alternator, then you probably have a grounding issue. Also, the numbers I used above are just for reference, the numbers you see may be different, point is you're looking for these values to drop as you make your way towards the battery.

Yes, i have been using a jumper box anytime the car doesnt start. Ill do the diagnostic test you described later on today. Ill also check out that ground strap.

Thank you to everyone who responded!

[Levanime]

looks like ground strap,
easy way to diagnose is, with jumper cables, connect one side to engine itself, other side to body ground location and try starting that way

[Cge92]

Ok, so I finally got to my car today with a multimeter.

First I checked the voltage values with the engine running.

Alternator to engine block: 13.95

Alternator to strut bolt: 13.95

Alternator to battery negative terminal: 13.95

Next I checked values with the engine off

Battery: 12.39

Positive terminal under hood to the ground bolt: 12.01

Starter positive to engine 11.91

Starter positive to strut: 11.84


I notice everytime I have someone try to start the car and I'm checking voltage at the starter terminal, the voltage drops to 0 for a moment then goes back up to the original voltage.

Looks to me that I'm losing voltage somewhere from the battery to the starter some how.

Anyone have any ideas?

[Cge92]

Car is fixed.


I was tracing the postive lead from the battery up to the starter. When i removed the battery i noticed the lead was slightly loose. Removed the nut and it was very rusty and corroded. Replaced the nut, re installed the battery and were good to go.


Little bummed out because i replaced the battery and starter for no reason, oh well. Lesson learned.

[nissubaru]

Originally Posted by Cge92

Car is fixed.


I was tracing the postive lead from the battery up to the starter. When i removed the battery i noticed the lead was slightly loose. Removed the nut and it was very rusty and corroded. Replaced the nut, re installed the battery and were good to go.


Little bummed out because i replaced the battery and starter for no reason, oh well. Lesson learned.

I replaced my alternator twice and the battery once chasing down the bad ground cable if it makes you feel any better lol

[streetpro]

I had issues with slow/weak cranking, occasional hickups such as no initially starting at all, second try went slowly etc... the grounding strap was all corroded and grey/green already... so I bought a 300mm/70mm2 universal strap, swap them and have a strongly starting engine ever since :-)