850 down a bank

[Sundancer]

1993 850, automatic, It started intermittent, the passenger side bank would drop out, giving me a transmission lockout and a fault code on the cylinder position sensor. it would do this about 3 or 4 days...now does it every start, it starts, runs on 12 for a few seconds then a bank drops out...

I swapped coils no change,

-swapped MAF,

-swapped DME harnesses,

-installed new plugs, it had Bosch F8LCR I replaced with Bosch FR8LC then replaced with NGK BKR6EK

-new plug wires

-new rotors

-new distributor caps

-checked fuel rails, fuel at back when cranking,

swapped pressure regs, but damaged one on removal, so waiting for replacement...

any other ideas, Could it actually be the crank sensor?

[XAlt]

Ok. Run a stomp just to see if anything's being stored, O2s, coils, etc.

Unplug one MAF so the opposite bank will run on 6 (with no connector, the disconnected bank will fire and stall almost instantly, hence the car being unable to run with both off). Check if both do so.

[koenig d]

25 year old fuel pumps

[Sundancer]

I'm on hold until I get a new pressure regulator...

[shogun]

Make a quick and dirty test http://bmwe32.masscom.net/sean750/fu...Regulators.htm
The M70 has 2 pumps, so 1 for 6 cylinders, each:
Bosch part number is 0580112507 (according to an old repair book)
operating pressure is 3 bar
conveying capacity at 12 V 1.7 liter/minute
capacity against counterpressure 875 cc/30 seconds
power consumption 5.5A

[Timm]

"runs on 12 for a few seconds then a bank drops out" is perfect behavior for a lack of the cylinder identification signal (the doughnut on leads 6 and 12) on the affected bank. The DME runs the car in lost-spark mode when first started and looks for the identification signal - if it doesn't get the signal it switches off the injectors as it believes there is no spark.

[shogun]

Here the testing data from the E32 book

M30/M70 ignition system data accdg to Bentley
Coil primary, coil code # 2051118335 terminals 1 (-) and 15 (+) resistance 0.50 ohm
Coil primary, coil code # 20510171101 terminals 1 (-) and 15 (+) resistance 0.37 ohm
Coil secondary, coil code # 2051118335 terminals 15 (+) and 4 (ctr. resistance 6.0 kohm
Coil secondary, coil code # 20510171101 terminals 15 (+) and 4 (ctr. resistance 9.0 kohm
spark plug ends 5.0+/- 10% kohm
shielded plugs 1.0 +/- 20% kohm
spark plug wires 0 ohm (approx.)
rotor 1.1 +/- 10% kohm

M70 firing order: 1-7-5-11-3-9-6-12-2-8-4-10
crankshaft position/rpm sensor: 540+/- 10% ohm

from workshop manual
distributor rotor 1+/-20% kohm
angled/shielded connectors 1+/- 20% kohm
spark plug connectors 5+/- 20% kohm
cylinder identification sender coil resistance at 20 degree C (68F) <1 ohm
pulse sender/crankshaft position sensor coil resistance 540 +/- 10% ohm
temperature switch for e-box cooling E32 750: switch on at 44 +/- 3 degree C, switch off at 36 +/- 3 degree C.

[72tpik5]

I am of no help here, but as usual, I am humbled by the knowledge and willingness of the members on this forum to assist a fellow 8er. Well done gentlemen, much respect.

[Sundancer]

It appears it was the crank sensor, well not the pick-up on the block, but the donut on the sparkplug wire...

[Timm]

No need for thanks!

https://www.bimmerforums.com/forum/s...3#post29781353

[Dr. T]

It appears it was the crank sensor, well not the pick-up on the block, but the donut on the sparkplug wire...

So guys, does this mean it requires an entire set of spark plugs or do we have a method of just replacing the 'donut' on the required wire(s)???

[Sundancer]

No need for thanks!

https://www.bimmerforums.com/forum/s...3#post29781353

Sorry , when I posted, it had run for 5 minutes, while exuberant with the thought of it running on 12, it was intermittent, so I was taking it cautiously : )

My apologies for not sending out more accolades, I did thank another individual that had helped out, not through the forum...

- - - Updated - - -

So guys, does this mean it requires an entire set of spark plugs or do we have a method of just replacing the 'donut' on the required wire(s)???

you could replace just the donut, by removing the plug boot, pulling the old one, and putting the new one on and replacing the boot. I in effect did this, I first tried to run the car with the old donuts on the new wires, then replaced the old donuts...

Even though I probably did'nt need it, After replacing plugs, wires, distributor cap and rotor, I don't regret doing it, there were signs of arcing, and wear, so it was time anyways...

[Sundancer]

sigh...its back...

no where as bad as before, but where it when it got worse, I get the trans fault safe mode alarm, but it clears and the car runs normal for a while...

[shogun]

Just a shot in the dark: do you have the chance to try another tested and working EML module for a test run? There was just a case solved on the German E31 forum, he tried for more than 6 months, changed a lot of parts, even changed the EML module twice.
Last week he tested the 2 EML modules on a friend's car, result limpmode, running on 1 bank only; so he installed another (the 3rd meanwhile) EML module and all is fine now. 2 EML modules he bought used were not working properly.

[jeffbebe]

I have a spare cyl 12 single lead with donut. Used but in perfect working order. More than happy to send (from New Zealand).

[Sundancer]

I have a spare cyl 12 single lead with donut. Used but in perfect working order. More than happy to send (from New Zealand).

I appreciate the offer, I do have a spare donut and wire that works,

I'm trying to track down another good EML, but not easy in my neck of the woods....

It is much better, the bank drops and comes back seconds later, before it would drop out on starting, and stay out...