E90 hard to boost is it just me?

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My trusty E46 always starts and cranks fast...

My E91 328 always cranks slowly and the really cold days no go. I have tried booster packs with no luck, did manage boosting with cables from my E46 but had better luck directly on the battery then at the front (but the front posts may need a cleaning)

I just added a ground strap to the motor, I have heard the one at the bottom corrodes.

For now I use a BMW battery charger when it's really cold.

May just need a battery but to my original question has anyone had any luck with a booster pack? I know the battery is pretty big.

Thanks!
 
The grounds do always go on those cars.. If the battery is shot you won't get it started with a booster pack at all you. You need a new battery. Costco has the H8 batteries for around 105$
 
I only had a problem when it was -22 or whatever...and I was able to boost from a car, not a booster pack

Otherwise it has been fine but I may do a battery, I usually do an original BMW battery as they are not that expensive but $105 at costco is super cheap, are they any good?
 
Yea no issues and you can return it after 4 years for a refund

How old is the battery in the car now?
 
So when I checked the last battery registration with BMW Carly it showed none...

I checked at the dealer and the battery was last changed in 2013 so time for a battery,

I ended up buying one at the dealer (I know but I am not costco member and my local costco didn't have any, it wasn't too bad at $260)

After installing I registered it but when I read out the battery it doesn't show it was registered. Not sure if it is a Carly glitch and if I should fire up my DIS

Thanks!
 
It's a regular lead acid battery if it has the same specs just drive. You only really need to program it if going to AGM..
 
That's what I figured, still cranks slowly, new battery and I added a big ground strap.

It always starts, it is just different then any other BMW i have had

Thanks for everything
 
That's what I figured, still cranks slowly, new battery and I added a big ground strap.

It always starts, it is just different then any other BMW i have had

Thanks for everything

The current draw on E90s and "modern" BMWs is nuts when you first press the starter button. I had checked the amperage once and it was around 30% higher than my E46. Starters fail because the grounds start to go or better someone puts those "thin" cabin filters in and water leaks down into the engine bay... and I've seen people change starters and still doesn't work because grounds.... Then you fry the comfort access module.

3 thick new ground wires two on the bottom and one on top does the trick. Watch out for a bad radio amp causing a current draw... I had this issue in my E90

The AGM batteries handle the "Start Stop" and efficient dynamics stuff better than a Lead Acid battery. It's not recommended going to lead acid as they can't hold up the constant demand. AGM batteries are also more stable... There are also EFB batteries. You need to be really careful with replacements now, its just not toss in a group wtvr and go.
 
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I don't have access to a lift right now so I put a big ground wire between a chassis ground and one of the big bolts on the alternator...

With the new battery so far so good, but it just doesn't crank like my E46 :)
 
I don't have access to a lift right now so I put a big ground wire between a chassis ground and one of the big bolts on the alternator...

With the new battery so far so good, but it just doesn't crank like my E46 :)

That's fine where it is. There is another ground by the boost point and exhaust manifolds.
 
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