Battery died!

[veeonfire]

Hi All,

Haven't posted for a while as I took my 840 (1998 CI Sport) off the road for a bit over the winter (worse thing I ever did!). I was driving it once a week to keep it going but hadn't used it for about 3-4 weeks until today and of course the battery was dead.
Call out the recovery guys and they jumped the car - she started fine.

The problem I now have is that the ASC light is on permanently - error code in INPA:
38 - position controller (ADS Part)
error frequency - 255
vehicle speed 2.75kmh (even though the car is stationary)
ASC passive
ABS control passive
Stop light switch off
ASC-control passive

The other issue I have is the car seems to have no power at the moment - I mean 0-60mph takes around 20 seconds and even if you floor it there is not much response. I have tried in D, S, and manual shift and it makes no difference - the car revs OK when in Neutral but whilst driving I have no power.

Any ideas as to what is going on? There are no other errors in INPA for engine or gearbox...
Any help / guidance is much appreciated as I would like to get her running properly again.

Thanks

[BobieM]

With these dual battery cars especially, there is a huge difference between a jumpstart that starts the car and having the batteries fully charged. I would shut it down, fully charge them (using the positive and negative lugs under the hood), then try again. The car really needs to be charging properly and have healthy batteries in order to have healthy electronics. Depleted batteries can really freak the electronics out. Your acceleration problem sounds like a transmission failsafe condition, which can also be a product of low-voltage.


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[veeonfire]

Thanks for the response. I did take her out for about an hour drive (no radio or lights on etc) and she now stops and starts as normal. Don't have the trans fail safe light on or anything on the MID - just the ASC light and the error in INPA...

[BobieM]

Give it a little time, let those batteries get up to a standard charge. I'm glad that things are smoothing out for you. I understand the panic I freaked out the first time I got a transmission failsafe status in my 740, due to a low battery. These cars have some nice self-protection mechanisms, but they can blindside you sometimes.


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[Timm]

Error 38 is an internal ABS/ASC+T code - the ABS/ASC+T module is possibly dead but may respond to disconnecting the batteries and reconnecting.
It sounds like you are stuck in 4th gear even though you have not seen the TRANS FAIL-SAFE PROG message on the MID. Did manually changing gear actually do anything? Did the tevs change when you changed gear? Did the gear position show in the instrument cluster?

The way I would play this is to buy a pair of new batteries (the old batteries would have died after a few days with zero charge) - charge both out of the car (new ones are not necessarily fully charged) and fit them, and then hope everything works - if it doesn't we will take you through how to get it going again.

P.S. Never jump start the E31 (or the E32 and E38), they don't like it, I have seen so many problems caused by this. It is always cheaper to buy batteries and carry them to the car than try and mend it afterwards.

[tangcla]

P.S. Never jump start the E31 (or the E32 and E38), they don't like it, I have seen so many problems caused by this. It is always cheaper to buy batteries and carry them to the car than try and mend it afterwards.

not to mention it's getting increasingly hard to find a car with enough current to be able to jump-start the dinosaur...

[veeonfire]

The car is not stuck in 4th gear and does shift up/down in both auto and manual modes. It changes at around 2-2500 rpm and will not let you rev any higher (or at least struggles to do so).
The jump start was done off the RAC battery pack - so not connected directly to another vehicle.
I did try clearing the code but it just came back. The breakdown guy tested the batteries and alternator and told me they were still about 70% and did not need replacing - do you think a good disconnect and overnight charge would do the trick? Or just replace them?

[Timm]

I would try disconnecting - charging - reconnecting. As the ASC light is on I would guess that presently the ASC secondary throttle butterfly is partially closing and reducing engine power - you could try disconnecting the plug to the ASC motor (shown below with BLUE wires going to it, just to the left of the two connectors) to see if you can go a bit faster!

[veeonfire]

Do I need to remove both batteries or can I charge them via the front points as BobieM said (where it was jumped from in the engine bay)?
Also - is there a preferred charger? The ones I have seen on eurocarparts say max 1.6 engine or max 1.8 engine....

[Timm]

No, disconnect the negative leads as detailed here:

http://www.meeknet.co.uk/e31/E31_Bat...eplacement.htm

and charge each battery in turn. For day-to-day battery maintenance consider using something like a Ctek MXS5

[veeonfire]

Just to clarify when you say disconnect the negatives do you mean charge in car or disconnect and remove both, then charge?


Thanks

[clubE31]

just ordered pair number 4 or even 5, lost count (4 years, 3 x 850's) ! (part of maintenance with these cars, especially if they sit for a while

[Timm]

You can charge them in the car fine.....

[veeonfire]

OK so I disconnected the ASC motor and she was slightly quicker - nothing major. Still struggles to get upto speed in D, S, or manual - but managed to get her to 80 (took a while). It feels like the accelerator pedal gets to a point after which it make no difference how much you press it, revs slow to climb, speed slow to climb (unless you press the kick down button - but still not a rocket like before).
Before I disconnect and charge the batteries - is there anything else to check as the ASC light is still on? Car started fine today and all electric in the car seem to be working OK.

@Timm - when you say charge whilst in the car, is the process to disconnect the negative on both batteries in the boot and then plug in the charger to both positive and negative in the engine bay? I have not done it this way before...

[Timm]

No, you need to charge the batteries by (after removing the negative leads on both batteries) putting the charger leads on, say, the left battery terminals and charging for a day. Disconnect charger and put the leads onto the right-hand battery and charging for a day.

I'm still confused as to why you have lost the engine power, the ASC butterfly seemed a reasonable place to start - if it made any difference I guess there is a possibility it is still stuck - but it seems unlikely.

What's the chances of:

Brakes stuck on (you would notice as when you took your foot off the throttle the car would stop quite quickly and the brakes would be smoking)
Something on engine damaged, MAF? Camshaft sensor?

For the next stage I reckon you need diagnostics for both the ASC and engine prblems

[veeonfire]

I changed the MAF about four years ago, and the camshaft position sensor about two years ago, and the brakes are not stuck as the car starts moving as soon as you take your foot off the brake.

The only error I get in INPA when running diagnostics is 38 in relation to the ASC - engine is clear other than that.

Do you still think it could be a battery problem or something else more serious?

[Timm]

I thought the problem was that your car was fine - then it was jump-started - and then it was broken. If that's the case then we need to keep looking for stuff that may have been affected by the jump-start, and that includes the things that were replaced a little while ago!

[veeonfire]

Yes it was fine up until the batteries died and I had to jump start it at the weekend.
If the camshaft position sensor was playing up I would get the phase sensor error in INPA (you told me this last time I changed it, and it drove differently when that had gone).
MAF - I am not sure what errors I would get but will check on INPA again tomorrow and post anything that comes up as I cleared everything on Sunday.

[Timm]

Use diagnostics to exercise the ASC butterfly and see if it actually moves - it is on the activate page of the ASC+T (F6) - it also should run when activating the pump (F5) as detailed here:

https://www.youtube.com/watch?v=-byfnSNeoy8

There isn't much that restricts the power without massive misfires and backfires except MAF, ASC butterfly and blocked cats (and a jump start isn't going to block them)!

[veeonfire]

OK so I ran the ASC pump test and yes you can hear the pump running during the test - ran it a few times to make sure.
Also found the attached two errors (38 - position controller and 10 - lambda probe before CAT) when scanning error memory in INPA
840 errors.pdf

I did clear these but they come straight back.
CATs were changed last year for Longlife sports CATs.

Are there any fuses / relays I should check or is it time for a garage visit?

[Timm]

Did the secondary throttle butterfly actually move (seen at 0:39 on video above)? Did you re-connect the plug that you took off?

[veeonfire]

Yes the secondary butterfly did move, and the plug was already reconnected after the last set of tests a couple of days ago

[Timm]

OK, then the ASC error is real and the ASC+T system is probably backing off the ignition timing - and is probably the reason for your lack of power! So, the next plan is to disconnect it - the problem is I've never had to do this so I can't give you full information of where it is, except that it is in the left-hand footwell.

Picture 2 here:

http://www.meeknet.co.uk/e31/e31_95.pdf#page=624

[veeonfire]

Many thanks - I will take a look this weekend and update. Are you saying, disconnect it and then drive the car to see if performance is back to normal?
If a control unit is faulty, I normally get a message from INPA to say it cannot communicate with it, so I am assuming this test is to verify the fault is somewhere else in the ASC system?
My initial thoughts on the error 38 position sensor were that it could be a wheel speed sensor, but again it does not tell you of a specific wheel, and normally is accompanied with an ABS light and strange cluster behaviour (which I do not have).

[Timm]

I reckon the ASC+T module is a bit upset and is reducing performance - the Error 38 is for the ASC throttle butterfly and I would guess that the module is reducing engine power in light of the error. Anyway, all just a guess, so disconnect the module and see what happens