bringing back a 92 BMW 850i V12

[850iBEAMER]

Hi,

I just bought a 92 BMW 850i. She wasn't running. Took me a while to get in the trunk with the batteries removed and manual trunk unlock not working lol. Got it all powered up. All fuses, relays... checked and cleaned. Reinstalled the door handle which was setting off the alarm which has now cleared. I started it up but it is only running on one bank 1-6 passenger side.

THE PROBLEM - when I first took a look at the car the girl that I bought it off of was trying to jumper the battery from the hood with no batteries in the trunk. She was connecting power to the drivers side coil pack instead of the positive charge terminal.

1. I am now getting a O2 overheating trouble code. I followed the path through the wiring diagram in the manual. I think the power flowed thru the coil, downstream of the fuse, thru the ECM and overheated the O2 when she tried to charge the battery. Could also have a ECM issue now that the O2 sensor heating resistor is burnt out, it could have shorted out the ECM. The ECM is still giving trouble codes so I think it is operational, but O2 heating circuit may be compromised.

Does anybody have the schematic of the 7-12 ECM (driverside).

2. I was checking the spark timing of the coil. The main power (high voltage) of the coil is plugged into the number 7 cylinder spark plug. This may also be why the 7-12 bank is not running. I checked the manual for the spark plug wire locations from the rotor but they are not identified.

Does anybody know what spark plug wires go where as I don't have the valve covers off. I also want to check the passenger spark plug wires too (bank 1-6)

Any help is much appreciated

Thanks ahead of time.

[TxGR8White]

If you look closely on the Orange distributor cap, the individual cylinders are numbered. The very center port goes to the ignition coil. The sparkplug wires should also have a corresponding number stamped on the wire. #7 = #1, #8 = #2, #9 = #3, etc.

[supavnick]

Timm's site is a life saver:

http://www.meeknet.co.uk/E32/V12_Distributor_Leads.htm

[850iBEAMER]

ya, I think I found the spark problem. Took off the cap and seen there was no electrode in the middle (main) that goes to the rotor on the left drivers side. The spring is still there but that's about it. The passenger side electrode in the middle was worn down to this tiny little ball. Just going go build a new electrode, stainless tube with a copper centre soldered at the top.

For the caps on the left side (sitting in the car) the main is in the middle, then goes to number 12 piston I think, has the timing coil around it (next one down), 4th plug down on the cap is #12 piston spark plug wire. On the right side (passenger) the main is in the middle (fourth wire down), then number 6 piston spark plug wire is just above it - has the current pickup for the timing (3rd wire down) so looks good.

Thanks for the timing info, cuts out a lot of guesswork. I see the timing pickups are on 6 and 12, the front of the engine, good to know.

- - - Updated - - -

Cleaning my MAF's, just want to check, flow arrow points in the direction of air flow?

Found some good pics, the arrow points in direction of air flow, a lot of good info on here.

Soon to be 500hp ) grrrrrr!

Did anybody ever stick a 255 lph Walbro fuel pump in their car. I want to power one pump and run naturally aspirated, then be able to switch pumps if I want, or run them both (supercharged)

1. Has anybody ran a 255 LPH Walbro fuel pump in an 850i?

[850iBEAMER]

Okay time for a serious question. LOCK MODULE INFO HELP NEEDED

I think I have a door lock module missing on the left driver door. Behind the door panel in the bottom front corner I have one module attached to the door. Then I have some power wire connectors and a data pin with nothing attached to it. It looks like there is suppose to be a module on top of the one that is there. The previous owner must of took it out. Now the door lock/unlock is on the fritz. Also messing with the trunk lock unlock. I'm thinking it is the door control module? Screws up the hole data network, DWA, trunk, doors, windows... I considered just trying to cut power to the door locks but it is all spidered together. I am speculating but I think the missing module(s) is kicking in my cut off relay, shutting down pretty much everything with the engine off.

1. Also missing a module in the rear drivers side (left) right above where the second battery is by the tail lights???

2. Can anybody tell me what the module on the lower front inside of the driver's door is? I think there are two, one ontop the other, I need to order one closest to the inside of the car but it is missing so need some specs please for a 92 850i with sport mode auto.

[TxGR8White]

How about snapping some pics to make it clear what you are actually talking about.
These cars have several plugs that do not connect to anything, but can make it appear as if something is missing.

[850iBEAMER]

The manual is garbage. Trying to find locking and alarm info is like trying to watch hell freeze over. No schematics for the input/output or power supplies. If I can't fix it just have to change over to some solid state switching with some mosfets I guess. The problem is that one module screws up the hole system. No fuses are blown. If it's not an easy fix just going to get rid of this 92 commercial crap and put some solid state industrial in it. Sick of having my trunk shut off. Maybe go with a compustar alarm for the locks which just sends a pulse out. Every thing works periodically, think the control I/O is getting messed up somewhere along the line. Getting locked out of my own car sucks. It's a made in germany car too, not sure if infared locking module was installed? I have a remote.

Just working on getting the caps and rotors back together - MAF cleaning. Will post some pics as soon as I can.

[acheson850i]

I hope you get the lock problems sorted out. I may be wrong on this, but I believe the trunk can be opened without batteries installed or discharged/dead batteries. The lock should be in the unlocked position and push up on the button with your thumb. I would be delighted to see what you mean by "get rid of this 92 commercial crap and put some soild state industrial in it". Not related to your specific locking door and trunk lock problems, but I have a friend who is working on a steering conversion (rack and pinion) and engine conversion to a LS1 V8...Not that I would do that myself, but each to his own! The car was definitely designed and made by Germans...they are smart guys ;-). Daimler, Benz and Wokke to name a few Germans! I am relatively new to this "field" but I have never heard of getting an increase of 200 HP by simply adding an additional fuel pump to system. Just curious!

[ManManinc]

He's figuring to get the walboro 255 boost pumps so that he can get the distribution he needs for the horsepower he wants to put out. These cars have two pumps but I don't know if you'll need to upgrade them if you are shooting for 500 hp. I guess it all depends on how many pounds he wants his injectors to put out.

[850iBEAMER]

Oh my god, converting to an LS1, while he's at it why dosen't he just throw a 4 banger in there lol. I think the car can easily make 500 hp, a lot of the tuners are over 400hp, and with a supercharger should not be a problem at all, probably have trouble keeping it under 800 )))))). I think a 255 LPH would supply me with enough fuel for 500 hp naturally aspirated. I was just saying pump 2 with another 255 LPH would be nice to transfer to if there was a problem with pump 1. Then when I get the time to mess around, I can run pump 1, switch on the supercharger (AC compressor pulley) and turn on pump 2. Don't really want to run 510 LPH if you are not using it, just heats up the fuel in the return line, think it would be a good setup. I see no reason in switching to an LS1, the V12 has way more grunt - torque which is rotational horsepower, the fun stuff. It's because it has more rotational mass, like hitting something with a sledge hammer instead of a finishing nail hammer. You can get 4 bangers to get 500hp easily too, but they don't have the torque, I have a Turbo Eagle Talon TSi AWD too. Torque is what gets you up to speed - acceleration. Hp will mainly just hold top speed. I like to spin my tires if you know what I mean, grrrr! That reminds me, why do I have polished 19" BMW rims, isn't everybody else running 18"?

THE M70 V12 IS CHOKED OUT FOR EMISSIONS. To get 500hp you need dual 3" in, dual 3" out minimum. Maybe start with removing the restrictor in the air box like I did today hehe, emissions garbage. Then with ported and polished heads, ported polished intake, a proper exhaust and a chip should be in the 400 - 500 hp range naturally aspirated, and torque numbers should be thru the roof. I was wanting a stick shift but think the autos handle big power better unless you have a 5G dogbox of coarse. So probably keep my auto trans and have a big hp cruiser is the plan.

Do you know if anybody has stuck a 255 LPH walbro pump in an 850i V16, I mean V12 lol? I think the factory pumps are dual 100 LPH, not enough, probably close to 100% duty cycle stock.

As for the module problem. Just going to open up my BODY ELECTRONICS MODULE (EKM) Everything runs through there, check inputs and outputs to see what's on or off. Factory stereo is out too, could be setting of a alarm trigger that is tied in with the hood. Radio is suppose to send 12V power to the EKM, if it dosen't it triggers the alarm I think, probably a soft alarm trigger as it is tied in with the hood. Will know more later, just researching it right now. I would post some pics but not at 100 posts yet.

I also made a stainless electrode for the main cap to rotor contact since the old ball electrode on the spring was either burnt up or missing. Should have it fired up tomorrow to see how the electrode works joining the cap to rotor. I cleaned my Mass Air Flow Sensor (MAF) today, had oil residue all over the resistor and plate sending wrong flow and temp data. Should be a considerable power gain. Did this on a mustang I had and was like driving a brand new car with replacement of the O2 sensors too. The front screen was banged up pretty bad, so I switched it with the rear screen. Then sprayed the resistor with electronics cleaner and hit it with 40 - 50 psi air nozzle. Just be careful not to go anywhere near the sensor wires, if you hit it you will have to buy a new sensor. Takes a considerable amount of electronics cleaner (LEAVES NO RESIDUE) to clean it because of the numerous spay cleaner, spay air without wiping the sensor wires. I was going to cut a big hole in my airbox to let more air in then discovered it is ram air. I took my headlight out and below the head light is a 3" rubber flex coupling. Mine was torn to shreds from those 300 kph runs I think. I just replaced it with a plumbing sewer pipe 3" flex coupling, worked great, very rigid compared to the old one. Just had to let it soak in some hot water for a while to fit it on. The damaged coupling I think was sending chunks through damaging the MAF screen, not good. At least it is fixed an I have my ram air back in charge. Plugs all back wired up and 7-12 bank ready to go. Any other car and I would be done by now lol. Like having 2 engines.

Another little trick I did was the MAF sensor should be oriented on top, that way if oil sprays back from the TB or vac lines the sensor stays clean.

One more question guys, says in the Body electronics module that the SIA reset is grounding out pin 8, 0 V when grounded signal applied at Pin 7 for reset to PIN 8.

Has anybody tried this, SIA reset connecting pin 7 to pin 8 in the BODY ELECTRONICS MODULE (EKM)????

[sleepy81]

Then with ported and polished heads, ported polished intake, a proper exhaust and a chip should be in the 400 - 500 hp range naturally aspirated,

Am reading with interest but I suggest you are way too optimistic. You will find via search that others have been down the 'port & polish' track. The heads are way too restrictive in their casting design to allow meaningful results. I would save time money & effort for the injector, SC, chip & exhaust modifications to approach the increases you desire.

[acheson850i]

To the OP...Thanks for your long reply and sharing your knowledge. You are my kinda guy!! Wahoo! I love your replacement of the rubber flex coupling with plumbing sewer pipe coupling...I had the same notion when I replaced and installed them on my car. Welcome to the forum and definitely do NOT heed any of my advice. Look forward to seeing some pics and riding in your 8! I just hope you are sober when I get to ride shotgun in it and let me do the the drinking! Sorry, cannot answer your question about the SIA(?) reset and the EKM/BEM). Thanks!

[TxGR8White]

the problem with making gobs of HP, is the 90 degree bend in the heads that make "free-flowing" air difficult - only if you ram a huge amount of compressed air will that work for you. Ah!, the beauty of forced induction...

[850iBEAMER]

500 hp is conservative if you ask me. I have a 2.0L that is capable of 1200hp, lots to work with. It is 4 valve though. I wonder if there is a way to fit a M50B25 vanos I6, 4 valve, 2.5L head to the M70 V12 5.0L 2 valve. The bore is 84 mm. It is 189 hp, so times 2 is 378 with stock setup. Where there is a will there is a way. The straight 6 is BMW's aircraft engine. With the 60 degree crank and 4 bolt mains on the M70, it can take a pounding, supercharger, turbos in the rear, or NOS. I kind like just he naturally aspirated though, hall azz all day every day. Could put a hydrogen generator hybrid setup in (hho), usually makes 35% to 50% power gains too. Just not sure if the head gasket could take it. Not really a head gasket I want to replace on a regular basis.

Got it running today. The electrode I made out of a stainless bolt to join the cap and rotor worked good. Ground it down, kinda made a little stainless bullet shape. Have pics and specs but gonna have to post them later. When I took off the cap, the one bank was missing the little ball electrode, and the spring was not pressing out far enough to the rotor. A spring looses it's spring when it is heated, so making a longer electrode compresses the spring more giving it better contact with the rotor. Since it was not being held tight to the rotor, I think the gap plasma discharge burnt up the little ball electrode, a spark plug before the actual spark plug. The rotor has evidence of a hole bunch of little pit marks that were very hard to remove from the centre. The plugs were burning cold too, very black. Also #12 cylinder plug wire was off hanging down the back of the engine, also fixed.

I still have to trace down a little toggle switch by the ebrake. I think the previous owner was shutting off one fuel pump, running one bank down the highway for fuel savings. The right bank, the one that is working right now, the wire heat shrink that feed down the front are a lot more brittle on that bank, could be because he was turning off the other bank making it work harder. I don't think he put a relay on the toggle (3A max), now it dosen't work the bank, will not turn back on. Also I am getting a Oxygen sensor overheat code. I think in turning off the bank the O2 sensor was never turned off burning it out (on it's own fuse with the power steering). Have to investigate it a bit more. This turning off of the bank could have also contributed to the burnt up rotor electrode increasing the resistance of the spark plugs with no fuel in the air. It is a smart idea, but needs to be done right. If you put it on a switch, cut off the fuel pump, coil, and O2 sensor heater on 3 NC contacts of a relay, that way if it does not work it will most likely close and run normally. Some electronic switches do not work below 5 volt, could hook it up to the speed sensor so it turns everything back on at a certian set speed - throttle position (highway cruising)....... Have to watch your load on the transmission too, will lock into 3rd gear (limp mode) if not reprogrammed (auto).

I also got the lock problem solved. I had one battery hooked up (Optima Red Top). It was fine when fully charged, but the car monitors the charge. Once in a while it was kicking in the cut off relay thinking the battery set was bad because it was only one battery instead of 2 (below 50% cut off). The O2 heater malfunctioning was draining the battery too, I pulled fuse 28, will zero in on it another day.

[850iBEAMER]

Jacked her up and checked her out. Have a leaky fuel system, could be one of a few problems with the left bank not running. Pulled the fuel pumps, on the inside of the tank, from pumps to the top lid the fuel lines are crumbling away. Also the in tank filter at the bottom of the fuel pumps is very dirty, clogging system. Will replace flex lines, internal and external fuel filters. Probably drop the tanks and give it a good cleaning too. I still have to test the pumps adding to my long list of new parts.

The transmission is only rated for 350 ft/lbs. Are there any other automatic transmissions I could swap in to get a higher torque rating? I have rebuilt transmissions before. I used red eagle racing clutches and really liked them but they don't seem to offer a set for the BMW 4HP24 automatic transmission. Are there performance clutches for the 4HP24? Does anybody have a link? The previous owner said that someone put in the wrong transmission fluid. Probably have to drop the hole trans to get all the fluid out of the torque converter. Mixing fluids usually grenades a transmission. If anybody has some helpful input, I am open to options.

Looking for a performance automatic or upgrade the one I have???

[Joe850V12]

Wow great project.
someone must be doing performance upgrades for the ZF trans or look at the late model 850ci to see if the trans is stronger

[850iBEAMER]

I was thinking of changing it from a 3 gear planet set to 6 gear planet set to handle more torque. There is already the centre pins there, just have to install 3 more planets from another set and tig them in place, dramatically increases torque rating.

Took out my fuel pumps too. My pumps where wired backwards in the tank. The front pump, pump 2 has the grey wire on it from the factory (factory fittings on pumps) It is suppose to be purple. What this ends up doing if there is a problem is shutting down the wrong bank. Gonna trace all the fuel lines and wiring to make sure it is right. Also the nut connecting the wiring to the pump is very rusted, going to switch it to stainless.

Pulled my exhaust to get a my tank so I can drop it. Only has dual 2" coming out of the cats. You need at least 3" dual for over 300 hp. I think it was reduced to improve emissions so it's a hotter burn out the pipe. Like I said, she's choked out.

[sleepy81]

Probably have to drop the hole trans to get all the fluid out of the torque converter.

If you can see the torque converter and it doesn't have a drain, drill a hole to drain & plug with a blind pop rivet.

[850iBEAMER]

There are so many things wrong with that advice sleepy, wow. Just not my style I guess. Drilling a hole in the torque converter would probably put shavings into the transmission system that is not even suppose to have lint in it, not a good idea. Also the torque converter spins and the turbines increase the pressure inside it, would spray fluid all over as a pop rivet is not a very good seal, maybe you mean pop rivet with a Oring lol. Probably still interfere with the turbines on the inside.

The proper way to get all the fluid out is to drop the transmission and torque converter, removing the valve body too for a 13 L trans fluid oil change as you are not suppose to power flush these transmissions. Or just drop the pan for a 5 L change. Most problems with transmission occur when the owner goes to switch the oil from standard, to synthetic thinking the fluid is drained, but gets a 50/50 mix of regular oil and synthetic which glazes the clutches burning them up. As much as it sucks, just going to have to drop the transmission, which means exhaust pipes, driveshaft.........

So, should be easy for me to drop when I fix the tank too. The venting is messed up. It is operated electronically into the manifold from my understanding. So if your butterfly valve on your throttle body is covered in oil, like mine was, or you have the batteries out of the car, or even drained batteries from the automatic cut off destroying the chargers and batteries, the tank does not vent exploding the vent line during winter storage, or vice versa. There is a vent in the door but think it is only operated during fill. Just going to fix the vents and be done with it, vent it by the gas cap like every other car on the planet. Something else to watch out for, in the 1992 manual for fuel, page 16-14/1 the rear pump is black violet (bank 7-12 - left) but on the next page 16-14/2 with the pump pulled the front pump is violet. An error in the manual. So much for german over engineering. Mine was wired with the rear pump violet, which is how the ECU is oriented so going to leave it that way. This non venting could have also contributed to the rapid breakdown of the couplings from fuel pumps to lines on the inside of the tank clogging the fuel pump filters on the inside of the tank also.

Thinking of just putting in an equalization line at the bottom of the left and right tank and get rid of the sender. Put pump 1 on the right, and pump 2 on the left with their own return lines, switch pumps to 255 LPH with one way backflow valves, have a selector switch to pick either pump 1 or 2, Y the inlets so have a true dual setup. Or could even wire it from the ECU inputs to the pump switches with LEDs on the switches to monitor the ECU shutdown of the banks, that are overriden by the single pump supply to both banks. Then have 2 spare vac lines for twin turbos later which would probably be slightly over 500hp

[PbFut]

back up to your battery issue a few post previous
Just a thought. The GM and the ELM have some capacitors starting to fail uniformly on these cars. There are 4 or 5 capacitors in the GM and 3 in the ELM. Changing out the capacitors in the GM fixed my battery drain issue and other odd happenings with the window, trunk, wipers, and probably a few other things I am forgetting.
I am also getting a random tail light and license plate light failure code at start up on cold mornings. Last week I found 3 capacitors in the ELM that I believe suspect. They are probably causing the codes since it is an identical fail to the GM issues and the same type capacitors. I received the 3 remaining capacitors in the mail yesterday and will be this weekend's project barring other life surprises. With the GM issue fixed, I am looking forward to no more random electrical oddities. This same problem could also be contributing to your issues but only a guess. Best of luck with your project. It will be fun to follow.

[Wuffer]

Not familiar with ELM - do you mean LKM - Light Control Module? Just to clarify.... 8-)

[legoman67]

500 hp is conservative if you ask me. I have a 2.0L that is capable of 1200hp, lots to work with. It is 4 valve though. I wonder if there is a way to fit a M50B25 vanos I6, 4 valve, 2.5L head to the M70 V12 5.0L 2 valve. The bore is 84 mm. It is 189 hp, so times 2 is 378 with stock setup. Where there is a will there is a way. The straight 6 is BMW's aircraft engine. With the 60 degree crank and 4 bolt mains on the M70, it can take a pounding, supercharger, turbos in the rear, or NOS. I kind like just he naturally aspirated though, hall azz all day every day. Could put a hydrogen generator hybrid setup in (hho), usually makes 35% to 50% power gains too. Just not sure if the head gasket could take it. Not really a head gasket I want to replace on a regular basis.

you should really do some searching before you get too carried away. You aren't the first one to try to get more power from a naturally aspirated M70. Head work, head swaps, etc, its all been attempted multiple times with limited to no success. The biggest problem with swapping the 4 valve heads is the driver side bank needs a "mirror" of it. Not to mention the oil and coolant passages don't line up on either side.

[DeadStar]

you should really do some searching before you get too carried away. You aren't the first one to try to get more power from a naturally aspirated M70. Head work, head swaps, etc, its all been attempted multiple times with limited to no success. The biggest problem with swapping the 4 valve heads is the driver side bank needs a "mirror" of it. Not to mention the oil and coolant passages don't line up on either side.

Legoman67 is right. This isn't your run of the mill small block that you can throw headers and cams at and make big power. It could potentially be done but then again you can do anything with enough money to throw at it. As others have said they respond well to boost. If you're serious about power you should really look into that.

[ocho50]

meeknet.co.uk is the place for you.