Big coupe, small garage - a BMW E24 adventure

or, just how many systems can previous owners mess up on a once-proud automobile...

It started out innocently enough with a listing on bringatrailer.com for an '84 BMW 633CSi. I was high-bidder on a reserve-not-met auction and made a deal with the seller to get the car. After some scheduling SNAFUs the car finally arrived in my driveway last summer.

From the auction description, I figured I'd do some relatively easy fixes and I'd have a reasonable fair-weather daily driver and potential HPDE platform in the future. 

Yeah, no...

My initial findings:

• Car wouldn't start after sitting for a few days, so I'm not sure exactly what electrical work was done by the previous owner. Put it on a trickle charger to get it running, and it would hold a charge better once I started driving it a couple of days in a row
• Once running, it was pissing power steering fluid all over the engine bay - I replaced the low-pressure hoses (which seemed to be the source). Still pissing a bit of fluid
• The straight-pipe exhaust was really loud, like, louder than any of my race cars loud

Got it registered and got a Reject inspection sticker (too loud, no catalytic converter on visual inspection) so I could drive it. Drove it to work a couple of time with the straight pipe and needed to jump start it to get it home both times. It also has an intermittent idle issue where is surges - sounds like I'm daring someone to race - which does not make many friends in the neighborhood, or with fellow motorists at intersections with the straight pipe.

Lou's Custom Exhaust quieted it down with a universal cat and a Flowmaster. Still has some "tone", but I was able to get it through inspection and not get so many headaches while driving.

Started driving it a bit to get an idea of what's what with the car (as opposed to what the seller said in the auction description). Overall, it's not too terrible, but definitely looks like it sat in the sun for many years - dash is cracked, leather is dried out, clear-coat has failed, and all of the rubber seals are dried out.

Now about those seller claims:

• Air blows cold - not so much, and the smoke billowing out from under the hood when I tested the AC on the way to work one day was an added bonus as the compressor seized and melted the belt

• Electric seats work as they should - also not so much. The car has "comfort" seats with a bunch of adjustments. Fore and aft are ok, most of the other adjustments don't work - lots of grinding gears from worn, or out of alignment stuff. I plan to ditch these and get something sportier and lighter (with manual adjustments)
• MPG gauge is fairly accurate - only if the car is off. It doesn't work at all
• Heat - When it got cool, I tried the heat and thought I was back in my '87 GTI with the leaking heater core, so that will need to be fixed. ...and the fan only works on high (control transistor needs to be replaced)
• Other electrical stuff - backup lights don't work (I suspect ground issues), dome light doesn't work when the door opens (likely the dimmer module), radio volume control very crunchy (needs to be opened up and cleaned)
• Needs idle control valve - bought one, changed it, idle still surges sometimes. Could be the idle module, could be a vacuum leak, could be other random electrical gremlins
• Odometer stopped worked - yup, it's not working, but there are relatively easy fixes for that
• Oh, and the tires are over ten years old and worn unevenly, so they'll need to be replaced, and the shifter bushings are toast, so they'll need to be replaced, too.

Once the weather started to turn cold, I put the car in the garage and started to dig into some stuff I could remove from the car and work on inside

Out came the cluster to fix the odometer - now it's a project

Took the cluster apart to replace the gears. Someone has been in there before. The SI board has been replaced with one without batteries, and someone did this mystery modification:

No sure what's being jumpered, but at least it's fused. A bunch of current does seem to have been flowing through the board, as the PCB under one of the resistors looks a little crispy. I removed the "mod" and will see what happens when I reassemble. If anyone has any ideas on what they purpose of this jumper is, I'm all ears - the collective wisdom of bigcoupe.com and bimmerforums didn't know...

I replaced the odometer gears (the original ones were seriously crumbly) and re-flowed solder joints on the speedometer and tachometer circuit boards (I had an '84 318i and re-doing baked solder joints cured many ills). I also took apart the radio and cleaned out the volume control. Everything's ready for reassembly.

Did a little more digging into the car. Pulled the heater fans out, and got to the fan-control transistor:

This board must have been touched by a previous owner, too, and the mounts were broken and the thing was wired in place..

Started to dig into more mechanicals as well. Apparently, the steering box mount is a weak point on the E24, and it seems to have broken on this car. I'm sure this is not a "factory approved" fix:

I was able to source a NOS front subframe from a seller on bigcoupe.com, which will be the next big project - I plan to reinforce the steering-box mount before I swap it in... May change suspension bushings, too, if I have everything apart.

That brings things up to now... With a little luck, I'll have it back on the road before the end of driving season here in New England.

Is there any recourse from BaT since the car didn't show up as claimed?  Or is it just "too bad, so sad"? 

Welcome to older German car ownership!  I have a '98 M3, they're great cars and I've been wanting a Shark for awhile...

Ed Raether sells a simple yet effective fix for the steering box mount:  http://www.mwrench.com  I have one in my e28 5 series.  As you probably know the e24 and e28 are more or less mechanically identical under the skin; I haven't personally had any of those issues, but I would suggest going to the http://www.mye28.com board for tech help.

In reply to docwyte :

It’s caveat emptor - let the buyer beware - part of the fun of buying something sight unseen via auction.

This is not my first old BMW rodeo, but it is my first 6-cylinder BMW. I’ve had a pair of 2002s, a very early E30 318i (before they figured out the pop-out rear window mechanism), and an early Z3 1.9 that I raced (ex-press-fleet car that was not eligible to be titled for street use). This is a bit more complex of a beast, so there were many more opportunities for previous owners to Berkeley things up...

In reply to stuart in mn :

I plan to either get one of those reinforcements and weld it in prior to installing the new subframe, or just box it in with angle iron for a more grassroots approach..

What odometer gears look like after they’ve baked in the sun for a bunch of years, and then someone (likely) hits the ODO reset while driving...

New ODO gears in place...

Aftermarket service indicator board that doesn’t have the perennially leaking batteries. Installed by a previous owner somewhere along the way. Don’t know if this is why the speedometer circuit was modified...

The 11-year-old baseball all-stars in my town went way further than anticipated this year, so the E24 has been languishing in the garage while I've been carting the kid to and from various tournament locations. With baseball season now over, i can start picking away at things again.

And now for something I can't blame (entirely) on the previous owner - interior light did not come on when either door was opened, but worked when switched to the on position, so I figured the fault was in the light dimmer circuit (the common element between the door switches). Taking apart the control module confirmed that maybe there's a little water dripping into the cabin (windshield seal? sunroof drain tube?) that caused a bit of damage to some of the electronics...

Cleaned-up ok. A couple of pitted traces to fix, and this might just be salvageable...

These really are strikingly good looking cars. I'll be following along as a warning to myself to not get sucked in by German beauty. 

Same platform as my fondly-remembered 533i. Your idle surging is probably a combination of vacuum leaks and maybe the idle control computer (a separate unit on 83-84 cars, IIRC). Since you already changed the ICV, replace the three hoses that go to it, the big hose from the AFM to the throttle body, and the plastic elbows if they're cracked, and see what happens. If it's still doing it, you may need to change the idle ECU (above the main ECU in the glove box, at least on the E28). Worst case scenario, try the penny mod: drill a small hole (I forget if there was a recommended diameter, or if it was a trail-and-error thing, but small) in a penny and stick it in the ICV as a restrictor. Solved a fair number of M30 idle problems over the years.

Oh, and the 3.73 rear end out of an E30 325is really wakes these cars up. Probably not so easy to find these days, sadly.

I had an '83 633CSi which looked very similar to that one- apart from the (many) failing electrical bits and disintegrating bushings, it was a fairly solid car and fantastic on the highway.  I miss looking at it, but really don't miss working on it 

As a guy that recently got sucked in by German beauty, i feel your pain. 

mazdeuce - Seth said:

These really are strikingly good looking cars.
 

Even so many years after being built, and even in less than perfect shape, the appearance of these things exudes wealth and seriousness.  Nobody calls me "sir" when I get gas in an old Japanese sportscar or on a motorcycle, but it's how I was addressed by even the grodiest of gas station attendants with the E24.

¯\_(ツ)_/¯ said:

I had an '83 633CSi which looked very similar to that one- apart from the (many) failing electrical bits and disintegrating bushings, it was a fairly solid car and fantastic on the highway.  I miss looking at it, but really don't miss working on it 

Yeah, I had an '84 318i which was WAY simpler to wrench on. The 6 has all of the high-end "features", but was ahead of the technology to actually make the features reliable. Too many individual wires and discrete electronics. Also a bunch of "why did they do it that way?" stuff like the two-stage, supposedly extra-powerful windshield washer system (which adds so many more components to fail), brake booster and power steering that share vacuum supply (so much potential for cascaded failures), and the like. I'm still torn on whether this will be a keeper, or not, but I'd like to get it running right before I make a final decision.

It's got enough issue with all systems that I'm on the cusp of either taking it all apart and restoring it (which would be more time and $$ than the thing is likely ever to be worth), or strip out all of the complex bits and go more in the direction of a track rat, which could be fun, but it's a bit "portly" to be a really good track car, and it's only the 3.3, not the 3.5, which limits its performance potential somewhat... It's a quandary...

In reply to 02Pilot :

I replaced the IC valve on the recommendation of the P.O.'s mechanic, but after seeing some of the "repairs" that were done on the car, I'm now thinking it wasn't the most sage advice and will likely go for the idle control module. The surging is intermittent enough that I'm thinking the issue is wonky old electronics rather than a hard mechanical fault. I don't know if the module is a single chip internally, or if there are discrete components that could potentially be replaced.

Back when I had my E28 the ICM was like $70, so you just replaced it (there were updated versions that helped with the surging). Now I see it's well up over $300, so pulling it apart might be worthwhile.

I think the 3.2 (yes, it's not actually a 3.3 - the beginning of BMW's misleading model labeling fetish, now taken to absurd extremes, but I digress) is a smoother motor than the 3.4 (again,...) for normal use, but it is a bit limited in terms of overall output.

If it were me, I think my inclination with a car of that era would be to start stripping out a lot of the troublesome luxo stuff and build a fast cruiser; almost in effect backdating the car to an E9 where possible. Take some weight out, take some systems out, build a nice suspension, and drive it. Sure, you'll probably have to fabricate some interior blanking plates, but nothing major. The only thing that would really bug me is chasing down endless electrical issues - if you think that's a real possibility, and it may be based on what you've already found, then you may want to move on to a better example rather than tearing your hair out for three years before giving up on it.

EDIT: I've got some E24/28 stuff left in my garage that I'd love to clear out (a bunch of Mahle oil filters, plus a few other thing IIRC). Let me know if you're interested and I'll see what's actually there. I'll let it go cheap - I want the shelf space back.

nlevine said:

¯\_(ツ)_/¯ said:

I had an '83 633CSi which looked very similar to that one- apart from the (many) failing electrical bits and disintegrating bushings, it was a fairly solid car and fantastic on the highway.  I miss looking at it, but really don't miss working on it 

Yeah, I had an '84 318i which was WAY simpler to wrench on. The 6 has all of the high-end "features", but was ahead of the technology to actually make the features reliable. Too many individual wires and discrete electronics. Also a bunch of "why did they do it that way?" stuff like the two-stage, supposedly extra-powerful windshield washer system (which adds so many more components to fail), brake booster and power steering that share vacuum supply (so much potential for cascaded failures), and the like. I'm still torn on whether this will be a keeper, or not, but I'd like to get it running right before I make a final decision.

It's got enough issue with all systems that I'm on the cusp of either taking it all apart and restoring it (which would be more time and $$ than the thing is likely ever to be worth), or strip out all of the complex bits and go more in the direction of a track rat, which could be fun, but it's a bit "portly" to be a really good track car, and it's only the 3.3, not the 3.5, which limits its performance potential somewhat... It's a quandary...

I spent about a year and a half before I gave up on my 84 633csi. All the reasons listed above were the final reasoning, and I can't imagine how anyone would even bother with an auto version. After going through the suspension and a handful of electrical/mechanical hiccups it just never really made me fall in LOVE with anything other than the looks. With all that said, I still regret selling it. Here's a picture I took the day my alternator took a crap on me.

Come for the build thread, stay for the group therapy session :-)

It’s comforting to see that automotive angst is a shared commodity...

That's a purdy car, if I come over can I touch it? or maybe sit in it? huh can I?

Snow-day update: Bought a new toy for the garage to help motivate me to get the E24 running this year. Saw this lift at the GRM Experience at Daytona and used my discount code :-)

Pretty easy to put together, and I like that it's all mechanical. One thing to note, though, is that the drill adaptors they supply assume a pretty hefty drill to raise, or lower the lift; bigger than the standard 1/4"  bit-size limit on most "regular" electric drills. Since you can't use an impact wrench, either, I used my air ratchet, with a 3/8" -> 1/2"  drive adaptor to motivate the lift. Worked well.

My only issue now is clearance - the E24 hood is pretty big, and my garage is really short, so I've got some issues there, and can't lift the car too high.

Once this beast is gone, I don't think I'll have the same ceiling-clearance issue with the Audi...

Threw in the towel and sold the beastie off. New owner is a has a shop a couple towns away with an M3 motor looking for a new home. With luck it will ride again...