Rough running on start-up - battery related? [SOLVED]

== Resolution Update ==

The rough running was solved by installing an Autozone 94R-DLG. Battery light no longer shows and the car runs very smooth after cold starts now + the transmission no longer makes really rough changes in the first few miles.

Another update after about six weeks: it seemed to take a few weeks for the new (unregistered) battery to be charged correctly by the car. The battery would be low after a week of my short commute so my wife used it for a week (8 mile commute, 80% highway). Since then it's been perfect even with my 3.7 mile surface street commute. Finally the DCAN cable arrived and I used INPA to register.


Dealer attempted to fix using the part numbers which made no difference:
New Battery cable, negative, IBS (12427603567 $ 217.24)
New Adapter for IBS (12517615476 $52.37)
New Adapter lead IBS (61129123571 $13.27)

The old battery would show green in its eye after being charged with a CTEK. Typically it would run fine on the next start but then be back to square one with the eye showing black.
==


Dealer is unable to resolve, they already replaced the Battery Module. 11K mile 2009 E93 that's garage kept.


This morning I monitored a few settings before a short ~2 mile trip, and then again returning home.

As usual it ran rough backing out of the garage and for the first few hundred yards.

In the images Volts (CM) is control module, Volts (Ad) is at the OBD port. ~8.5V and ~9.5V seems really low. On returning home voltage was stable and there was no rough running/ engine surging.

Does anyone else with the ELM 237/ Torque setup have the time to monitor their voltage on a cold morning start?

A CTEK 7002 says the battery is ok. When time permits I'll pull the battery and run the CTEK's recondition mode. This rough running is not the end of the world but is annoying.

Wouldn't the battery only affect the actual initial ignition? After that, it is just being charged back up, but has no role in how it runs (unless you have an electric supercharger). Varying voltage could be a result of the engine not running smoothly (electrical power once running is drawn from the alternator, which is driven by the engine).

Did the dealer check the fuel pump and injectors?

Dealer found fault code 2E8D and replaced the intelligent battery sensor. These parts are listed on the worksheet:

New Battery cable, negative, IBS (12427603567 $ 217.24)
New Adapter for IBS (12517615476 $52.37)
New Adapter lead IBS (61129123571 $13.27)

The image from this morning probably included cranking. I'll run the app again resetting after cranking on the next cold morning. It's had one bottle of Techron through already. In a month or so I'll put another bottle through with on 1/4 tank. Would do it now but I change the oil every-time something like that is used.

After reconditioning the battery next on my list is looking for air intake leaks. I put in a new engine air filter already (previous one looked almost brand new). The low battery light has not show since I bought the CTEK.

Could be a failing ignition coil.

Originally Posted by tturedraider

Could be a failing ignition coil.

Was thinking that too. No codes so far. Maybe after trying other alternatives I'll buy one and swap it day by day between the plugs.

== Resolution Update ==

The rough running was solved by installing an Autozone 94R-DLG. Battery light no longer shows and the car runs very smooth after cold starts now + the transmission no longer makes really rough changes in the first few miles.

Dealer attempted to fix using the part numbers which made no difference:
New Battery cable, negative, IBS (12427603567 $ 217.24)
New Adapter for IBS (12517615476 $52.37)
New Adapter lead IBS (61129123571 $13.27)

The original battery would show green in its eye after being charged with a CTEK. Typically it would run fine on the next start but then be back to square one with the eye showing black.

==

Originally Posted by MP3_E46

== Resolution Update ==

The rough running was solved by installing an Autozone 94R-DLG. Battery light no longer shows and the car runs very smooth after cold starts now + the transmission no longer makes really rough changes in the first few miles.

What's your year & mileage?
_____________________________

Edit: Saw your other thread.

"This a 2009 E93 with 11K miles on, I've done 700 of those including one long weekend trip."

Not driven much - BMW's warning evidently true!

Originally Posted by CALWATERBOY

What's your year & mileage?
_____________________________

Edit: Saw your other thread.

"This a 2009 E93 with 11K miles on, I've done 700 of those including one long weekend trip."

Not driven much - BMW's warning evidently true!

Attachment 355039

July 2009 E93 with 11.4K miles today

Another update. Left the radio on while cleaning the car today and the darn low battery light appears. Watch this space... the rough running was obviously voltage related as it's been fine for days now. Perhaps this car has a very high standby current drain?

The CTEK is actually taking to charge it this time so that battery must have become discharged. The CTEK runs through the charging mode in under ten second on the MX-5 so I know it thinks this battery is not charged now.

Perhaps battery registration is necessary so the car know it can now charge the battery for longer? Am ordering parts for this and it'll be a project for next weekend. Was close to ordering a BavTech but would like to disable the seat belt gong so it's worth the time to get this coding up and running.

Still it ran a full battery down in a matter of days so I think it has a high current drain even when locked. Might put a multi-meter between the -ve terminal tomorrow and see what it reads.

Originally Posted by MP3_E46

Another update. Left the radio on while cleaning the car today and the darn low battery light appears. Watch this space... the rough running was obviously voltage related as it's been fine for days now. Perhaps this car has a very high standby current drain?

Happy holidays fer ya:



.

Originally Posted by CALWATERBOY

Happy holidays fer ya:

Thanks, looks good from the comments. If (when?) my multi-meter test shows current drain I'll check this guy out.

Am now pretty convinced the previous owner threatened to lemon this car which is why it went to auction in such good cosmetic shape with such low miles. Dealers would normally put this kind of car back on their lot rather than auction it.

Car draws ~0.5 Amps even when locked until standby mode arrived. At 11 mins I was worried to see it still read ~0.5A, but by the time I'd returned from an errand run (different car!) the reading fluctuated between 10 and 20mA in sleep mode. Obviously the multimeter is in series with the battery.

Walking up to the car with the CA Fob did not do much. It read 0.02 (20mA) more often 0.01 (10mA). Touching the CA handle skyrockets amps -probably beyond the meter's (20A) range- but it soon settles to ~16A with the headlights on and 6A with lights off. Within two minutes it's down to 0.74A. Within 29 minutes it was down to 10mA. Conclusion: Sleep mode works fine without having to lock doors.

I'll update what it eventually falls to with the doors left unlocked and CA Fob in the house.

This is my multimeter from secondary school A-Level Electronics, I did not want to risk damaging it in mA mode so used A mode hence it reads 0.01 for 1mA. Modern ones may have overload protection, I know most auto-range these days.

Hope this info and pics assist other debugging battery/electrical issues. This a 2009 Non-nav, non I-Drive E93 but has Bluetooth (I verified Bluetooth sleeps down too by using the phone; its Bluetooth could not see the car).


At this point my theories are
1. Without registering the battery it does not charge correctly
2. Something is faulty with the charging system
3. My short commute can significantly drain the battery in three or four days

1 sounds unlikely to me but guess I'll order a BavTech and try it first. 3 seems highly unlikely unless there is a massive current drain when running.
Anyone have other theories? It has a new battery and new IBS module.

The alternator is presumably strong as once the rough running was over with the original battery the car ran fine; i.e. the alternator kicked out enough power to run the car.

I believe you can do voltage charting with the elm bluetooth module and torque.

So if the voltage is above 13 you are putting charge in the battery . You could run a chart
for your in town driving. When I have the car running mine reads between 14 and 14.5 volts.

But it you lock the car doesn't it do into sleep mode within a minute.

Originally Posted by ctuna

I believe you can do voltage charting with the elm bluetooth module and torque.

So if the voltage is above 13 you are putting charge in the battery . You could run a chart
for your in town driving. When I have the car running mine reads between 14 and 14.5 volts.

Good idea. I'll register the battery first as it's easy (if expensive to buy the BavTool). Have a lot on at (real) work this year so finding time's going to be tricky.

Another update after about six weeks: it seemed to take a few weeks for the new (unregistered) battery to be charged correctly by the car

The battery would be low after a week of my short commute (light came on) so my wife used it for a week (~8 mile commute, 80% highway). Since then it's been perfect even with my 3.7 mile surface street commute

Finally the DCAN cable arrived last week (almost four weeks to arrive from Hong Kong!) and I used INPA to register. IMO the car had eventually figured out how to charge the new battery before then

Should be this final update! I know it'll help others hence am taking the time to post all relevant details.

Today I tested the Ah of the CTEK reconditioned battery. It measured 46Ah using the equipment shown (attached). Its rating is 90Ah but likely it really had ~80 Ah when new.

So I believe if we'd kept running the car for a few weeks with the CTEK reconditioned original battery it would have worked fine. Remember the (non registered) new battery did not hold a charge for at least a week.