Purchased yesterday - FailSafe driving home.

[Indigo46n2]

New owner, but not new to cars. Bought a 2001 740iL. Did not know about this problem:

Trans FailSafe Prog.

Ive read recent posts, everyone has their own unique symptoms.

Previous owner said "Timing chain and guides were just replaced, coolant flushed and oil changed. By the way *THATS A NEW BATTERY*." Car physically drove like a 2018 champion during 5 min test drive. Indash display screen blank. Telephone missing, but radio and all heating/interior lights still work. Electrically she seems sound minus indash display.

40 mins into a 6 hour drive home, battery light, ACS, Brake, ABS and Passenger Airbag lights. 10 minutes later, FailSafe limp mode and stuck at a rest area. Turned her off in panic when the gas would not respond. Imagine my face when I thought my transmission had shattered or something else crazy.

Found this forum and some youtube videos. Disco'd my ABS module at two connectors, had a second look at the trunk battery: there is no rating or date on it, no brand name, only a big green sticker that says "ECONOMY" leading me to believe previous owner had electrical issues and found the cheapest battery he could so it would be ok for a test drive.

Jump started, 10 mins later FailSafe and same lights. Ran and bought a voltmeter, battery read 6.5v. Shes a goner. Bought a battery from Walmart, h8 for $130.

12.85v while disco'd
12.6 while connected in trunk across terminals
13.45v while idle running
14.44v while 2k rpm.

Ran her for 3 hours trying to get home Asap at 85mph 3k rpm trying to maintain alternator charge, then FailSafe.

11.6v idle
11.9v at 2k prm, I witnessed the voltage slowly decreasing as I held the leads on the terminals. She dropped to 11.00 and then 8.5 in maybe 5 minutes. Rpm surges, batt light flashes, engine shuts off.

Alternator was making an attempt but the battery would not sustain. In my inexperience I suspected a bad component drawing heavily upon battery. Constantly got the message "check rear lights/check lic plate lights" upon startup and shut down. Found a light bulb sitting dislodged inside rear right taillight housing with no harness connected, but no harness in sight and no visibly cut wires. Brake lights blinkers and running lights all seem to work fine all around the car, but the message still displays.

I pulled multiple fuses before learning you could shoot power across fuse terminals, including anything related to ABS module, cd changer, satnav, alarm, telephone, garage opener, interior dome lights, sunroof, leaving only bare essentials like fuel pump/engine control/speed control/heater cores etc. Battery continues to actively drain while engine running and at elevated rpm.

I am towing the car tomorrow to my home and planning to order an alternator, I am on a budget and hoping to order one refurbished from ebay for less than $300 to replace myself.

Before I do so, I was curious if any new information has come out recently in regards to parasitic drain? Any ideas? The posts about "2 alternators and 3 batteries later still broken!!" are terrifying to my wallet.

[Narlift]

Sounds like alt is toast. going out.

[jclausen]

Second alternator

[Timm]

If the battery light comes on that means the alternator is not charging - so either it is not spinning (belt slipping) or it is dead - and I'm afraid we get a lot of dead second-hand alternators. Here's how to replace it:

https://www.meeknet.co.uk/E38/Altern...eplacement.htm

The 'battery' light is directly connected to the alternator (which is processor controlled) - the processor continually checks the health of the alternator - if it fails in any way it will illuminate the 'battery' light.
P.S. Forgot to say - they often start failing when they heat up - classic case of failing electronics....

[Indigo46n2]

Thanks everyone, and thank you Timm for the link. Looks like Ill be giving into that this weekend and will follow up when its complete.

Minus this issue, Im absolutely in love with her and glad to now be apart of the club!

[740ilDuke]

E38's are super finicky when it comes to power. AGM batteries are a must. Alt's are all remanufactured at this point, even from BMW. The best bet I've seen has been AutoZone. Its about $400 but comes with a lifetime warranty. Mine's been in 2 years, no issues. Hopefully this solves your laundry list of issues. GL!

[Ruskii]

Please keep us posted if new alternator solves your issue! And welcome to the club!

[georgebest]

E38's are super finicky when it comes to power. AGM batteries are a must.

+1 get the biggest AGM battery you can fit in

[Indigo46n2]

"AGM" battery?

I had no idea autozone offered warranties on our alternators, looks like thats the move Im going to make.

[Narlift]

"AGM" battery?

I had no idea autozone offered warranties on our alternators, looks like thats the move Im going to make.

Bad move bud...unless you are OK with changing it out 4 times within a very short amount of time and just end up going with a better one anyway..
Its a lot of labor man to have to just do it all over again because the cheapo rebuilt autozone alt failed and they do.....often. be warned!

[racer2086]

AGM = activated glass mat battery. Superior to the regular lead-acid batteries. I only use those now after having some lead-acid batteries leak on me and go bad in short order.

I also agree the alternator is probably your issue. The main thing is getting a good one. I don't know about South Dakota, but there are a number of shops around me that will rebuild alternators. Depending on who, they can use quality parts (e.g. Bosch) and do a much better job for less money than one you would get at Autozone in addition to being thorough and honest. Last alt I had rebuilt cost me about $100. It was for my Mustang, but they looked at my BMW alt when I had it out and said it was in great shape and not to touch it.

[georgebest]

What "BMW remanufactured" means? https://www.fcpeuro.com/products/bmw...x5-12317508054
I somehow doubt that BMW cares about remanufacturing alternators. Or is it just a genuine BMW remanufactured by somebody?

[Grady in Texas]

For what it's worth, I had an alternator that failed overcharging. I bought a used one but my local guy's alternator rebuilding guy kind of rejected it based on the condition of the winding. So I'm having my old one rebuilt and will pick it up the car up in the morning. Fingers crossed.

[carnut1947]

My water cooled alternator failed. I bought an $80 kit from a vendor on EBAY. This is a "brushless" alternator. The kit included the regulator, bearings and diodes. Fairly simple to rebuild. It's been running great for a year now. And I agree an AGM battery only.

[Indigo46n2]

Ill definitely be investing in a rebuild kit in that case, as for now we will see how necessary this lifetime warranty is gunna be.

Ive checked different websites for AGM batteries, none of them say their batteries "fit" our model. Is there a specific type or website I should order from?

Also curious about Timms write up that says "BMW COOLANT ONLY". Closest BMW dealership is 6 hours away, should I order some from an online vendor and wait or can I use an alternate? Alternator came in yesterday so Im doing the swap now and just finished draining all coolant.

[Timm]

I say to use BMW coolant as we have good information regarding the properties of it - and it is the same stuff all around the world whereas other makes are unknown to me and not universal.

[Indigo46n2]

Thanks sounds good. I procured some from a fellow bmw owner, 3 gallons of it. Just finished the alternator swap, the coolant filling and bleeding process seems more complicated than replacing the alternator and Im super intimidated lol.

Any hindsight tips before I get started? Ive seen videos and everyone seems to do it differently

[purplecty]

Remove engine cover and put something to catch the coolant under the expansion tank. Put something in those little flaps on each side by the firewall to keep them open but be careful as they can get brittle. Turn ignition on and turn temp to 90 fan speed on low and unlock the cluster to see the KTEMP at test 7. Remove bleeder and cap and fill coolant to the top of the tank allowing the bubbles to escape from the open bleeder screw. Keep filling it to the top of the tank for a few minutes until all of the bubbles have escaped. Re-install the cap and screw, start the engine and crack the bleeder screw at regular intervals to see if more bubble escape (I usually do not let the ktemp to go above 70 or 80c when I stop opening the screw and make sure you do not get a check coolant on the cluster during this procedure. There will be plenty of coolant to bleed off though so this really shouldnt happen). I usually then let it idle or go for a spin making sure the HEAT feels good on both sides of the cockpit and watch the KTEMP on the cluster making sure it does not exceed 110c. If it does let it cool and bleed it again until the temps stay at or below 110c. When the engines cools off in the AM check the fluid level and top off as needed. Full coolant is the top of the floater level with the rim of the tank. There is a pic noted on the tank right next to the cap which shows how it should be when full... Good Luck!

[Indigo46n2]

Remove engine cover and put something to catch the coolant under the expansion tank. Put something in those little flaps on each side by the firewall to keep them open but be careful as they can get brittle. Turn ignition on and turn temp to 90 fan speed on low and unlock the cluster to see the KTEMP at test 7. Remove bleeder and cap and fill coolant to the top of the tank allowing the bubbles to escape from the open bleeder screw. Keep filling it to the top of the tank for a few minutes until all of the bubbles have escaped. Re-install the cap and screw, start the engine and crack the bleeder screw at regular intervals to see if more bubble escape (I usually do not let the ktemp to go above 70 or 80c when I stop opening the screw and make sure you do not get a check coolant on the cluster during this procedure. There will be plenty of coolant to bleed off though so this really shouldnt happen). I usually then let it idle or go for a spin making sure the HEAT feels good on both sides of the cockpit and watch the KTEMP on the cluster making sure it does not exceed 110c. If it does let it cool and bleed it again until the temps stay at or below 110c. When the engines cools off in the AM check the fluid level and top off as needed. Full coolant is the top of the floater level with the rim of the tank. There is a pic noted on the tank right next to the cap which shows how it should be when full... Good Luck!

Hey thanks man. Ill be checking in the AM for any leaks.


Unfortunately folks, I still have a problem. I just swapped the alternator, bought a new AGM h9 95r battery and threw it in. 7 minutes into just idling I got the battery light. I dont understand wth is happening. Battery is already reading 11.96, down from 12.85 before I threw it in.

[purplecty]

Hey thanks man. Ill be checking in the AM for any leaks.


Unfortunately folks, I still have a problem. I just swapped the alternator, bought a new AGM h9 95r battery and threw it in. 7 minutes into just idling I got the battery light. I dont understand wth is happening. Battery is already reading 11.96, down from 12.85 before I threw it in.

Where did you get the alternator from?

Sent from my SM-N910T3 using Tapatalk

[purplecty]

Bad move bud...unless you are OK with changing it out 4 times within a very short amount of time and just end up going with a better one anyway..
Its a lot of labor man to have to just do it all over again because the cheapo rebuilt autozone alt failed and they do.....often. be warned!

I've seen them fail out of the box...

Sent from my SM-N910T3 using Tapatalk

[Indigo46n2]

Before I chalk it up to bad out the box, is there anything else that could cause the drainage? Any obvious signs of a system drawing too much power besides the battery draining?

[Indigo46n2]

The alt came with "Computer Tested Results":

Max Alt Outout: 187 Amps
Max Output Power: 2527 watts
Volt reg set point: 14.4v
Leakage Current Tested at 12v: 1.95mAmps
Ripple Current at 2500 rpm: 38 Amps
Turn on speed less than: 1600 rpm

Regulator Functions Test: Within Specs


Output Tested at 13.5v:
1800rpm = 104 amps
2000rpm= 123amps
3500rpm= 172amps
6000rpm= 187amps

[purplecty]

The battery light means the alternator is not functioning at all...

Before I chalk it up to bad out the box, is there anything else that could cause the drainage? Any obvious signs of a system drawing too much power besides the battery draining?

Sent from my SM-N910T3 using Tapatalk

[Indigo46n2]

Whats the best way to check power at the alt itself, and can I do this while the engine is running without damaging other components? Most of the old threads Ive searched through have pictures that are removed/missing and Im not sure whether to shoot on the connector plug(wired portion) or a point on the alternator.