E30 Zone

A guy from work has just bought an E31 850i V12 specifically to take him and the mrs to france on work business in.

unfortunately they left yesterday and it started to missfire on cylinder no1 (front right i believe) 50 miles from the border of france, he carried on hoping that he would be able to get to a garage in france

however 10 miles from the border it died and he had to be recovered back to devon in england.

took it home, and changed the plus and leads, and cleaned all the contacts on both dizzys and rotor arms. the miss fire is sorted, however it still doesn't run right, and it smells like its overfuelling to hell....

he has to be there on monday morning without fail, and has to take a car with him to get around once over there.

does anybody have any clue what-so-ever as to what might be wrong with it? i.e. had a similar problem etc.

things considered so far are:
Lambda sensors ( i believe one in each exhaust)
AFMs (clearly 2)
Crank positioning sensor (CPS)

any help would be appreciated so so much


cheers for the time guys.

possible ecu fault, iv never had to work on one of these as they are so reliable, there should be two lambdas in each exhaust, one near the manifold and one b4 orafter the cat i think

ajm-e30 wrote:possible ecu fault, iv never had to work on one of these as they are so reliable,

You're having a laugh right? My dads was the most unreliable car ever...

iv nver had one in the garages iv been in, and 15years mate

Hmmmmm, my dad obviously had a bad 'un.

He did have a misfire changed all HT leads etc but then never had problems after that. Sorry can't help out any more...

you may have to get a sparky out mate, but you'll probably find it will cost a small fortune as it will have to be plugged in to a scanner

i have ecu's, maf, throttle bodies, injectors etc for a 750 which should still be the same.

if you find what the problem is gimme a shout as i may have the bit you need.

Scoupe wrote:A guy from work has just bought an E31 850i V12 specifically to take him and the mrs to france on work business in.

F**k me, the eternal optimist. I wouldn't trust an 850i to make the ferry.

It would sink the ferry!

Tell him to get rid of it and buy my 535i sport

nickso wrote:i have ecu's, maf, throttle bodies, injectors etc for a 750 which should still be the same.

if you find what the problem is gimme a shout as i may have the bit you need.

may well get back to you on this one on sunday evening. although we are in Devon, and you appear to be in scotland...so exchanging parts for dollar could be interesting!

At work we have a Wurth diagnostics system, which is worth a silly amount of money, and was bought about 2 months ago, although unfortunately it appears to lack the capabilities to diagnose the 850i. I fear this may be due to BMW not releasing the relevant information to make this possible. Which would leave only a BMW main dealership who could diagnose it with the OEBD port. And they charge silly amounts of money for it . Although it looks like that could be the way it is going.

It drives so at least getting it there isn't a problem!

Have been working at it since 6 now, and we haven't really got any further which is a little irritating, mainly because nowhere seems to have the data to support the tests that we have tried.

In some cars (mainly from my experience Vaux, and Hyundai) you can touch two pins in the diagnostics plug together, and it will flash the fault codes through the engine light on the dash.

If anyone knows how to do that it would be absolutely magic.


Cheers for all of the input guys, greatly appreciated.

use a snap-on scanner, works everytime and the 850 is inthe vehicle menu

if it isn't running right, it could be in 'limp home' mode because of a stored fault code in one of the ecu's.
you can clear the fault codes by diconnecting both battery terminals,
and then hold both terminals together (not touching the battery obviously!!) for a few minutes.
hope this helps
glenn

Scoupe wrote:

nickso wrote:i have ecu's, maf, throttle bodies, injectors etc for a 750 which should still be the same.

if you find what the problem is gimme a shout as i may have the bit you need.

may well get back to you on this one on sunday evening. although we are in Devon, and you appear to be in scotland...so exchanging parts for dollar could be interesting!

In some cars (mainly from my experience Vaux, and Hyundai) you can touch two pins in the diagnostics plug together, and it will flash the fault codes through the engine light on the dash.

If anyone knows how to do that it would be absolutely magic.

im sure we could work something out.


iirc the bmw ecu can indeed flash the fault codes through the engine light.........but bmw didnt connect the light to the ecu in order for it to do this on uk spec cars. im told is a fairly simple affair to connect it up but ive not tried it yet.

I have just looked up 'optimist' in the chambers dictionary. The meaning they give is ' someone who buys an 850 assuming it will be a reliable form of transport'
Tell your mate to park it and buy a xantia, at least if it makes it to france all of them frog mechanics will be able to fix the turd !

Make sure both batteries are absolutely fully charged and will hold a charge. There are two and you need both - it will not function on just one. On E32 autos a low battery will bring up 'Trans program' and go into limp home mode.

Hateful sacks of shit. They make a Porsche 928 seem like a really good idea.

haha okies will try the ideas tomorrow morning, he has been persuaded into flying to france now, but obviously still wants the car when he gets back

I think they are a really nice looking car (obviously not as good as an E30) ..but I m detecting a certain lasck of love for them on here!

cheers again guys

they look fine... go fine (when they work) but from what I can gather... if you're not a bmw technician or have an endless supply of money, they're not worth a sniff.

I hope you get it sorted though afro boy.

Oh and if you dont, and he decides to scrap it, I'll have the engine

lol...i'll swap the engine for the bourbet b's in your sig (and on a serious note if you wanna sell them then PM me!)

been through a bit more today after the suggestion of the batteries....and the alternator is buggered.

only puts out 9v ....so ordered a new one from our local bmw garage.....£450!!!!!!!!!!

gonna fit it tomorrow, and see if it makes a difference

500 and they're yours.

£450!

no.

£372?

no

...once again you appear to have hi-jacked my topic

a little bit too much dollar for me at the moment mate, but cheers anyways

The 850i has DME's (engine control units) iirc, one for each bank. Faulty ABS sensors can incur running problems, due to the sensors being connected to the DSC control unit, through a bus network, to the DME's. Me and Tee had massive problems with Miniblob's 850CSi before he stacked it

It sounds like the misfire has stored and fault and needs to have the DME's fault memories cleared and if possible, the adaption values reset.

And NEVER, confuse an 8 series with being reliable

lol cheers mate...had the ecu reset by our local beemer dealership to start with, after the software we had wasn't any good, and it didn't make any difference...

after that we replaced the alternator, after finding charging problems with the one that was on there, and now she runs sweet as.

im pretty sure that "reliable" wasn't my idea, but in fact the guy who bought its' idea! he stands by the bloody things

Scoupe wrote: after that we replaced the alternator, after finding charging problems with the one that was on there, and now she runs sweet as.

I thought that might be the case. V8 and V12 BMW's need absolutely 100% batteries and alternators. Fit a duff battery and it'll come up with 'trans program' in no time. They systems on the car are draining the battery faster than the alternator can charge it.
Once the early gremlins were sorted out (mainly the EML throttle motors on 87-89 750iL's) the V12 cars were pretty reliable on the whole.