wont start, been sitting a while.

well.. looks like I might need some help. (850 M70 auto)

My car has been sitting outside my house for about a month because of my diff issues.
Got the new diff in yesterday, but because I had my door open a few hours the batteries were drained when it was time for a test drive.
It would not even start with jumper cables.
It turns over, but it just wont ignite, I smell fuel from the exhaust and it sounds like it want's to start, but just cant get the right mix.

I left the car charging over night and was just outside to try and start it.
It did not start.
Well.. after I floored the accelerator it ran on 6 cylinders for a while.
however I had no RPM reading, fuel gauge was working though.
Once I stopped it it wouldn't start again, but I guess the batteries lost a lot of charge during my attempts.

Thinking about a "reset" by disconnecting the batteries for a few hours while they charge and give it another try in the afternoon.
could it have got some sort of hick-up when I tried to start it on drained batteries?

Are there any fuses that could possibly cause something like this?

Zitat von schnitz850;101712

Hey Noggie...

These are so temperamental with a low voltage and take a couple of days to charge both batteries!!

You could either leave it charging on the front terminals for a couple of days or disconnect your batteries and charge individually to make sure they are both fully charged and in good condition....

I would try the latter before replacing anything......

Alex

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I have a c-tek smart charger, the batteries were at 75% this morning, should be plenty to make it start.
I was running it on the started for a long time, at least 4-5 times of 10 seconds each, could hear it sputter and trying to start, smelled unburned fuel from the back, but it just would not start.

have disconnected the batteries to reset an should have the batteries at 75% again this afternoon.
Will do another attempt in about 5-6 hours.

Just had another attempt, no go, would not start at all. had the batteries disconnected for 3 hours so that should be enough for a reset.

I will have a look at my lambdas if they were damaged by accident when we changed the diff.
Other than the spedometer sensor we did not disconnect anything.

Zitat von Timm;101716

As Alex said, it sounds like your batteries are not charged sufficiently - the C-Tek charger will take at least 50 hours to get a reasonable charge in them. Don't take any notice of the charger's indicator, it is not at all accurate. It appears you have enough voltage to spin the engine, but insufficient to get a decent spark.

As the engine is now flooded make sure the batteries are fully charged before attempting another start or you will be back to square one again.

I have a big c-tek, a 7 amp charger, so it should be able to top both my batteries in about 20 hours.
There is plenty of power in the batteries, I must have run it on the starter for close to 60 seconds in total on my last attempt, and if there is enough power to do that it most certainly is enough to make a spark.

Zitat von anguswolfendale;101717

Noggie, how much of a job was this? I have a 3.91 LSD (was taken out of DickB's 840) sat in my workshop awaiting me to have the courage to tackle the job - just need some pointers as to the main issues, order of procedure etc.

Took us about 5 hours out in my drive.
We had to move parts from the old diff to the new one, and we had a long coffee break, so 4 hours should be possible.
You need to drop the exhaust, and the center bearing on the driveshaft.
the drive shaft is 6 nuts
the output shafts are 12 allenkey bolts.
the diff is held by 4 bolts, two at the front, two at the rear, the rear ones are a bit hard to get to so you need a long 18mm socket.
But two guys can easily do this in a day/evening.

Zitat von schnitz850;101719

As Tim said... 90% + will do...

Starter runs off one battery and the engine management runs off the other. That is why when you get the dreaded non start or intermittent cut out it is the inline fuse from the right battery....

Both my batteries took almost a week to charge from the front terminals (from flat) so would be quicker singularly with a full charger and not a condition/charger.....

Diff can be done in 1 1/2 hours. Worst bolt is the top one....

Alex

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I have my charger hooked to the left battery with a quick disconnect..... now where is that fuse, I've heard of it but never bothered to look for it.
It's that flat metal thing right? that vibrates and breaks over time.
I'll go and have a look.

Thanks.

I checked that hidden fuse and it looks good.
I checked the fuel pump fuses, all good.
I then pulled the fuel pump relays in the DME box and put the ignition to pos 2
now I expected them to trigger when I inserted them, but they did not.
It's been so long since I drove the car that I'm not sure if the pumps run or not, but I thought so because of the fuel smell from trying to start the car.

Might get a friend over this evening to help me out a little, will let the batteries re-charge until then.

SUCCESS !!!!!!

It turned out to be the damn fuse link after all.

I pulled a plug on each bank and bank 1-7 was dry, bank 7-12 was wet.
Measured over the partly broken fuse link and it was 8 volts on the car side, 13+ volt on the battery.
Soldered the link as a temporary solution and with it some help with jumper cables and eventually it started.

Just to find out that my gearbox is also broken, not just the diff.
It will only run in 1st and reverse, 2nd, 3rd and Drive is not working, looks like another trip to the tranny shop

Zitat von SmileitsMe;101730

Hi Noggie!

maybe there are some electrical gremlins..
incomplete charged or fault batteries can cause some funny errors..

So charge the batteries and disconnect them from the car (over night) to clean error history if you dont have something like DIS to do this.
also make some sync drive after reconnecting batteries.. (for DME)

Maybe it helps..

greetings Richard

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I'll give you a rundown on the whole story.
Had my Gearbox rebuilt in May/June. Drove to a meeting in Sweden, came back, when visiting a friend I floored the car as I was about to go home, big bang and I suspected the diff broke.
Yesterday I replaced the diff and it was indeed broken.
Then these starting issues, and now it appears that the gearbox is also damaged.
Since I had it rebuilt and reinforced only weeks ago with a 2 year warranty I intend to take it back for them to have a look.

Since the gearbox works in first and reverse but not in the other gears or D, I suspect it's a mechanical issue in the gearbox depending on the selector as it is also mechanical.
I did try my spare gearbox control unit but it had no effect, so I doubt it's electrical.

Zitat von steve;101739

Be aware that your batteries probably won't hold their charge as good as before they were discharged.
I had strange issues with my one year old batteries after they went flat.
Altough I recharged them completely (I have a CTek as well) they were loosing their charge in days and the car produced strange errors.
After reading a thread from Martin and Christoph regarding Megapulse, I tested it and got them back to around 90-95%.
(strangely, my problems with very low idle RPM is also cured with the revitalised batteries... )
As Richard said, batteries are funny things in the 8 Series.

Cheers,
Steve

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Well... gearbox shop is closed until Monday, so no news there.

Batteries.
I battled for 3 years with new batteries.
The car was dead in 10-12 days, I kept recharging for 3 years believing it was a tracker that drained them, before I found that one had a faulty cell. And that battery kept draining the other.
Got two new ones last October had them fully charged, and the car started without any problems after sitting for 3 months.

The recent drain was because my drivers door was open for about 5 hours during the diff swap, this was enough to drain the batteries to the level where they no longer could turn over the engine.
The fuse link breaking during this time is probably just a freak coincident.
Anyway, the car is running and the batteries charged, just need to get the gearbox fixed.......again.
Looks like it will be late August before I get to use the car.

2012 has been the worst of my 6 years of ownership, so far I have only had the car on the road for 1 week this year.
With luck I'll get to drive it in September, if I'm not sent away for work.
October it's time for winter storage.

I guess my problems with this is not over.

I got my car back a few weeks ago and it ran rough, figured it was because the DK's where out of sync.
Sunday I needed to move the car, it started, really rough, and as I pulled out if my garage it died, and has not started since.

I thought it might have been the fuel that had gone bad so I started flushing the lines by disconnecting the back of the fuel rails and running the car on the starter (not the best way but it works).
After having flushed about a liter I noticed that just one of the temporary hoses I had hooked on to the fuel pipes was wet.
I split the hoses and tried again and this confirmed it, just one pump is running.
The car gets fuel to cyl 7-12, but not to 1-6.
Hidden fuse is ok (voltage checked)
Fuel pump fuses are OK (Ohmed)
Measured over the fuses when cranking. Fuse 24 (pump #2) gets 11v. Fuse 23 (pump #1) gets 0,5v.
My conclusion is that whatever sends the signal to run pump #1 is not sending it.
From what I can see it's K210 that sends power to the fuse, and K210, I cant say if that relay triggers on my own, so I need someone to come over and help me.

This leaves me with two options.
1. Relay triggers. meaning input voltage on the contact is not present, this comes from X6400 terminal 30, this also powers a lot of other things, like the DME 1. and is the 50A fusible link aka hidden fuse.

2. Relay does not trigger.This means that The DME #1 is not triggering the K210 relay, or there is no power output to K210 from K212 (from hidden fuse) or the DME is not triggering K212.

Looking at this I need to take a closer look on my hidden fuse as this is a major part in distributing power to the involved componets, or my DME is broken, and I need a new one. will try to swap my DME's too.

Right..... Since I was looking at the schematics while writing my previous post I got some ideas so I went out in my garage and did the following.
-Swapped DME, no change.
-Checked hidden fuse, 13v after the fuse.
-Checked relays K212 and K210 (along with K211 and K213 for pump #2), all have power where they are supposed to have power.
-Put 12v on the pump fuse, pump starts and fuel flows.
-Checked wiring between K121 and 210 to the DME plug, Ok.
-A neighbor came by and we concluded that it was K210 (pump relay) that did not trigger, swapped them, but no change.

I'm out of Ideas, it looks like the DME for some reason does not trigger K210, Since I have swapped my DME's I think they are OK.

Anyone know if there are any sensors or inputs that control the DME enabling the fuel pump?

I just pulled the battery grounds and will attempt an overnight reset.