Teach me 750iL???

I went by to check on a Garage door I was having installed for a customer..

Of course in the small garage is a 1989 750iL

Supposedly the fuel pump(s ?) died 5 years ago... and there it sits..

Generally they are good about maintaining stuff and the car looked to be no exception to that.. It just broke one to many times I guess.. and was replaced with a newer version of the same..

It was covered in a thick layer of dust.. but no signs of anything major.. Honestly I didn't look all that close. But I had to ask him about it..

What is something like that even worth first not running.. then running? Assuming free labor will the parts alone kill me on something like this? What breaks.. yada yada yada...

Electrics - redundant/duplicate systems 2- ECUs for example, I see quite a few runners with around 750-1500. Typical bmw stuff like plastic cooling parts. Running/working maybe 2000. Little value, can be expensive to fix. Personally consider it about the least desirable bmw.

the V12 on those cars have weird injection systems. It is basically 2 I6s joined at the block and crank.. hence the need for two ECUs

Nothing aftermarket can't fix and do better

They were awesome cars, but resurrecting one that broke and has been sitting for five years just doesn't make sense financially.

Is it really true that replacing the battery is a 7 hour job?

What is the cost for new pumps? and what kind of a job is it? would be my fist questions. Then price out all the rubber bits (hoses belts etc). Get this number and add it to what they are asking and you have the base cost of the car.

I have always wanted to take one of those and add LSx power. I see them for sale quite often around here in the $1000 range.

If you even manage to get the V12 running, you will be moving on to the goofy self-leveling rear suspension and the six miles of wiring for all the electronic doodads (power REAR seat and all). The E32 generation's electronics are a bit "challenging," according to many owners.

I was shopping them pretty hard for my dad, then started looking at 740i's as they're a lot simpler, then ended up with a 528i, weirdly.

They are not worth a whole lot even in good shape because when something goes wrong, it is ludicrously expensive to fix.

If this thing is in decent shape I might suggest getting it out and attempting to get it running in the most direct way possible. Try to make the stock parts work, if they don't, replace them with something that is easier to deal with. This is GRM after all. I just can't bring myself to say "Don't take that rust free German missile." If you have the technical ability to fix and/or upgrade then I think that this is a great project. Just my thoughts, I am not too familiar with the BMW 12. However, they do sound amazing when uncorked.

Jay_W wrote: Is it really true that replacing the battery is a 7 hour job?

The battery is under the back seat, which is electrically operated. I think the 7 hour figure is if the battery has died, and you have a dead electrical seat in the way.

singleslammer wrote: I just can't bring myself to say "Don't take that rust free German missile."

i can. RUN AWAY. i can personally guarantee an investment of 30 man hours and $500-$1000 in the first 200 miles. after that, another $1k, another 30 man hours, another 200 miles. if your lucky enough that the twin throttle body idle motors aren't seized/shot after sitting ($400 each up), the water pump radial seal isnt dry rotted (ive done over 1000 w/p's in my life, the only worse one is a X5), the radiator end caps aren't brittle and leaking, the oil seals from the VC's all the way down to the pan aren't cracked and leaking, and the seals and solenoids in the trans aren't all boogered and clogged, even if all this turns out to be fine, there's still about 500 other things i bet i can find wrong with it.

RUN AWAY.

unless you are ok with a full teardown, re-gasket, re-ring and re-everything electronic...in that case go for it keep us all posted!

-J0N

stuart in mn wrote:

Jay_W wrote: Is it really true that replacing the battery is a 7 hour job?

The battery is under the back seat, which is electrically operated. I think the 7 hour figure is if the battery has died, and you have a dead electrical seat in the way.

There certainly must be some way to jump start the car.. providing enough juice to move the seat.

but with no enablers around here.. I think I have my answer...

Offer scrap price (or less) and wait...

ronholm wrote: There certainly must be some way to jump start the car.. providing enough juice to move the seat. but with no enablers around here.. I think I have my answer... Offer scrap price (or less) and wait...

On some cars with a remote battery (MINI Cooper S, for example), there is a positive jump start terminal in the engine bay. I don't remember if my E30 has one.

My take on a late model 750: Buy a clean, rust free example, strip it down to remove as much of the potentially troublesome bits as possible, sell off said parts (profit!) and rebuild the car hot-rod style with a LS and aftermarket wiring harness and vintage air HVAC. The only OE electrical bits I'd probably keep would be the windows... maybe... depending on how difficult fitting a hot rod kit would be.

Yes, it would be a crap-ton of work and wouldn't be worth much, but in the end you should have a fairly reliable cruiser that probably gets better mpg than the V12.

I have never worked on any German luxo/sport barges but they either must be ungodly hard or expensive or both because I see these things at the local bone yard all the time sitting right next to the lowly Hondas and Kias. It's simply amazing that the big BMWs , Mercs and Jags end up there when they appear (outwardly) to be in good shape.

mguar wrote: In reply to Ian F: Chances are darn good that the V12 is fine.. Hot rod the V12 with a mega squirt. Put a couple of small turbo's on it and the thing will awesome..500 plus horsepower an an insane amount of torque.. Stuffing a Chevy V8 into it wouldn't achieve anything.. Still a heavy complex car prone to breakage..

It's not just the V12, it's everything else hung on it and attached to it. A transmission rebuild would exceed the value of the car. While tools are available to deal with VANOS, they aren't cheap.

I don't think you understand my idea... it would look like a BMW, but that would be about it... but like I said, that's the only way I'd get one of these...

Besides, I didn't say it was a good idea...

I am well aware of Allards, but I'm getting the impression you aren't all that familiar with BMW's...

The only thing I can add to this is that every BMW pro tech I've ever spoken to about the V12s has indicated that they are something to be actively avoided with the same vigor as man-eating sharks and tuberculosis.

02Pilot wrote: The only thing I can add to this is that every BMW pro tech I've ever spoken to about the V12s has indicated that they are something to be actively avoided with the same vigor as man-eating sharks and tuberculosis.

I have heard the exact same thing. The super exotic V12 stuff like the 850csi etc is really cool, don't get me wrong. Really, though, the M60/M62 V8 is a better engine in every way. Especially if I'm the one turning wrenches on the damn thing! I've seen a few 7er V12's under the hood and I wouldn't know where to start...

I daily drove one for a little over 5 years. It had 98,000 on it when I got it and 205,000 when I gave it to my mother-in-law. While I had my share of problems, nothing really seemed much more difficult to fix than any other car. I did a water pump twice. The second time was because the brittle plastic fan broke and the resulting vibrations destroyed the water pump. I replaced a radiator (fan blade went through it). I fixed a few oil leaks.

I doubt the fuel pump is the reason it's not running. As others have mentioned, it's basically 2 six cylinder engines joined at the crank. There is a separate fuel pump for each bank. It will run fine (with significantly less power) if one fuel pump dies.

It is possible to remove the rear seat cushion even if the battery is dead, though it's easier to just jump to the terminals under the hood for that purpose. I can't see how it would approach 7 hours either way.

I never had any problem with the self leveling rear suspension, but maybe I just got lucky.

I remember reading an article on a hotrod that used the BMW V12.. it worked VERY well and was very unique. They too mentioned that getting rid of the stock ECUs and injection made working on the engine MUCH easier

There are 8 to 10 of them in the Atlanta area PullAPart yards. I'd be happy to get whatever you need.

T

The V12 is actually pretty good with aftermarket ECU. Matt at DiyAutoTune can hook you up on that.

Most forget all the systems in the 750/850 from that era is the equivalent of TWO engines in one car. If that can be simplified and you can deal with some "super" luxury items not working, it would be a hoot (if the price is right of course).

The M70 (8.8:1) with two T25 or T3 turbos will make stoooopid amounts of HP and TQ without much effort. However, a manual transmission option is an expensive venture.

With talent and fabrication skills something else could be adapted to an M70 V12, but the only factory BMW bellhousing and transmission that will bolt up is the one out of a 850 and they're pretty hard to find. Another problem with these engines is they use drive-by-wire throttle bodies, but I believe you can adapt a couple throttle bodies from an M20 'baby six' without much trouble.

I think the Swedes used M30 TBs for some non DBW setups . . .

I believe the flywheel for the M70 and the M60 (V8) share the same bolt pattern. The GM Auto used has a removable bellhousing, so you can get an adapter made (think 1UZ-FE and the W-58 & R-154 adapter). For a guy like me (no shop equipment), I call that expensive.

There was a guy out there that adapted the Getrag 265 using the auto bellhousing to a M70,

Check this out:

http://forums.bimmerforums.com/forum/showthread.php?t=1453720

I was asked to do another project over there.. So I had to take another look..

The back seat is already removed to access the battery..

Fuel pumps are out and in the trunk

and cooling fan and shroud have been removed..

It looks like it might be pretty nice under the dust.. but I am waiting for the call..

dorri732 wrote: I daily drove one for a little over 5 years. It had 98,000 on it when I got it and 205,000 when I gave it to my mother-in-law.

How bad can it be? He gave his high mileage one to his mother-in-law. Brave man!