New-to-me 1992 735iL – the fun begins!

[shogun]

I do not have the VIN, my 750iL 11/88 is different from 735iL 12/91, when I use a EURO version it should look like this http://bmwfans.info/parts-catalog/E3...trical_system/
2 tanks, "intensive" maybe just means yes: headlight washing. On my 750 the intensive (concentrate) tank is on top with the large tank, that looks like this http://bmwfans.info/parts-catalog/E3...trical_system/
the small container at the bottom #23 is called Fluid container 61671390635 from 09/88. My tank on top is the big one for water and the small one for concentrate http://bmwfans.info/parts-catalog/E3...ld_cleaning_2/

[Cactuar]

Thanks for the info Shogun, this confirms that I don't have the intensive wash system.
I guess BMW used the same code for the headlight system and the intensive wash system.

[Cactuar]

In progress in the garage: changing the transmission mounts.
Finally got the old mounts out today, penetrating oil was crucial to get the top nuts off.

The difference between old and new is obvious. Both are Genuine BMW. The old mounts were collapsed but not torn, just very deformed. The top metal "hat" sunk into the rubber.
The new mounts should restore some smoothness in the drivetrain.

mounts.jpg

[Cactuar]

Tonight I inspected the driveshaft center bearing with the driveshaft still installed in the car. I moved the shaft up and down and could see the rubber flexing correctly, no cracks or major signs of wear. I did see some kind of flaking on one side, shown in the pics below.

I don't get any driveshaft related vibrations, at least none that I can feel. Should I still replace the bearing? How can I determine if it's bad?
Is it possible to make the driveshaft turn while the car is jacked so I can hear the bearing? Maybe I could put it in neutral, but I don't want to damage anything so asking first.
Thanks in advance for the advice!

Front side
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20201101_001608.jpg

Back side
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20201101_001425.jpg

[shogun]

you can turn one of the wheels to turn the driveshaft, no problem. Usually the bearing of the center bearing is not the problem, the rubber between the bearing and the outer metal ring breaks. You could still leave the center bearing installed and check it once a year, as you do not drive anyway that much.

[a777fan]

Yeah, unless you are it itching for something to do, I’d leave it for now. Sounds like you don’t have any play in the bushing or rubber. Additionally, you’d hear/feel a CSB if it was going bad. Yours doesn’t look too bad given its age!

[m60power]

If you don't have any driveshaft vibrations and your center bearing is not making any clicking or knocking sounds on acceleration, then I would leave it be. Not worth the hassle unless it's failing.

[Cactuar]

Thank you for the tips guys. I'll leave the center bearing alone for now and watch for vibrations and noise in the future.

One of the six bolts holding the heat shield above the exhaust was very hard to remove, it became cross threaded while removing it. No idea how that can happen, all the other bolts came out easily. It's a good opportunity to order this thread chasing kit by Lang: https://www.amazon.ca/gp/product/B00...K6Y9EEQB&psc=1

[zapass]

In my case two bolts from trans bracket and one from heat shield were corroded on the end. It was hard to remove them because this end, damaged by corrosion, had to go all the way through threaded hole, probably damaged it a bit. I put new bolts using lower torque than specified.

[Cactuar]

I fixed the threads using the kit I posted above by Lang, it worked very well.

I reinstalled the transmission bracket and noticed that the bracket is shifted slightly (2-3mm) laterally compared to the previous position. I can see the witness marks where the bolts used to be installed.

Does a difference of a few mm matter for the transmission mount? I hope not because I reinstalled the exhaust and would have to remove it again to fix it!

[zapass]

I would focus more on trans position itself, not bracket. Question might be how to measure it. I do not have good method.
You can move bracket with exhaust installed. I removed bracket completely with exhaust installed.

[Cactuar]

Good point about the transmission position, I didn't think about that.
If anyone has any tips I'm all ears...

[Cactuar]

Well the replacement of the transmission mounts is done. I showed how I went about it in the video below.

I wish I had two jacks (and a car lift!) but even with only one jack I managed to get the exhaust out of the way to replace the mounts.
The new mounts greatly reduce the amount of vibrations in the cabin so I am pleased with the fix!

[Cactuar]

I was driving the car tonight and paid attention to the fuel economy meter (I usually ignore it).
It goes to 30 L/100km when I come to a stop at a red light, that seems kind of odd.

In this video I go from 0 km/h to 45, then 0 again.
Can someone please confirm if the meter is behaving correctly?

Also I realize this meter is more of a novelty than an accurate measure of fuel economy. I just want it to behave correctly like BMW intended!

[zapass]

For me- works ok

[kce1900]

Nice music! Who's the composer? You're still driving? My cars are in storage since Nov 1st.

The economy meter divides two measurements: fuel flow (volume per time) and vehicle speed (distance per time) resulting in volume per distance. When the speed approaches zero, the result of the division gets larger and larger, and that's why you see readings like 30l/100km. This is normal. When stopped, it's trying to divide by zero and that's why the needle disappears. (Cars showing MPG do this calculation the other way around.)

I trust this instrument only at constant speeds, preferably with cruise control engaged. At highway speeds I find it actually accurate. The one that I have in my Chevy is really a "novelty", it has only min and max, no numbers.

Shortly after I bought my car I replaced the grey cluster with a blue one. After the swap, the consumption shown by the economy meter was clearly too low. I had a look at the wiring diagrams and found that my early car was wired for only one fuel consumption signal from DME I (the M70 has two DMEs). The cluster doubled this measurement. Later cars were wired for fuel consumption signals from DME I and II and added them. Since the blue cluster wasn't getting this second signal, the readings were wrong. I ran an additional wire to supply the missing signal, and then things made sense again.

[Cactuar]

The music is from baroque composer Antonio Vivaldi, the title is Concerto in A Minor part 1, RV 523. It is part of the double concertos from Vivaldi (double violins in this case). My recording is from the 1960's, playing from a CD in the CD changer. Vivaldi is by far my favorite classical composer.

Your explanation helped me understand the economy gauge, thanks! So it looks like it's correct and working, good to know.

Yes I still drive the car, the insurance is valid until Nov 30th when the insurance is automatically paused for the winter storage period.
I had the car on jack stands for too long this year and really miss driving it! I have a nice 2h trip planned for the next week-end.

[kce1900]

Vivaldi was my guess. Just wasn't sure because I don't know much of his music. I do like baroque music, but my all-time favourite composers lived a bit later: Mahler & Shostakovich. And another is still alive. In both videos you can actually see me very briefly in the audience.

I hope you're going to have nice whether next weekend!

[Cactuar]

Thanks

I still get quite a bit of vibration in the engine bay. I tried putting my jack under the oil pan while the car was running and I can feel vibrations in the handle of the jack.

The engine mounts and transmission mounts are new. Could any other wear item cause vibrations?

[Cactuar]

Received my automotive test leads kit, now I can provide 12v to the windshield washer pump for diagnostic. Sure enough it doesn't power on. The headlight washer pump squirts fine.
Is this all that is required to conclude that the pump is bad?

[theBMWbeast]

Yes

[Cactuar]

Great thanks for the quick reply, I'll order a new pump and sealing grommet from BMW.

- - - Updated - - -

By the way this would be my ultimate electrical troubleshooting kit!

https://www.amazon.ca/POWER-PROBE-Ma...D36NHTCZ0J3V34

https://www.amazon.ca/ICARSCANNER-Au...omotive&sr=1-9

Such cool tools but very hard to justify the cost as a week-end mechanic!

[CamE32]

Received my automotive test leads kit, now I can provide 12v to the windshield washer pump for diagnostic. Sure enough it doesn't power on. The headlight washer pump squirts fine.
Is this all that is required to conclude that the pump is bad?

FWIW my washer pump also died. I simply swapped over the one from the intensive cleaning tank (the small auxiliary tank) and it was an exact fit - but I'm not sure if that's possible with the headlight washer system on your car.

[CamE32]

Last weekend I met up with the mechanic who sold me my car (he helped me undo the stubborn collar nuts to replace my front shocks) and I mentioned our rough idle problem. I explained all of the things we've addressed/done to troubleshoot.

He thinks it could be 1 of 2 things:

1) a tiny amount of corrosion may have formed around the valve seats/seals (this might be more applicable to my car since it sat for ~12 years)
OR
2) spark plug gap - too big of a gap can lead to what sounds like misfires

I've always gapped my plugs to .3 (right in between .28 and .32, per the manual's guidelines) but now I'm going to try .28 and see what happens! Wish me luck.

[Cactuar]

Hopefully the re-gapped spark plugs make a difference on your car! Let us know how it goes.