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

[Cactuar]

After youngbimmer's post I went and verified the fuses and relays in my car. Thankfully they were all clean.

Pic of the defogger fuse removed. Almost all the connectors were this copper color, is that expected?
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All looking good under the hood:
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I checked if my car had a vent tube for the battery and all I found is a hole in the floor, no tube (top-right corner in the pic).
No rust fortunately, just some dirt stains.
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So then I looked on all the sides of my battery and I couldn't see where a tube goes? Maybe in the top section on the side? There are small holes there on both sides. Or maybe my battery doesn't need venting...?

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[Cactuar]

Ok yep, the two small holes are the vent holes. One hole should be plugged with a cap, and the other hole should have a tube running to outside the car.

The plug is included with the ACDelco battery but the previous owner didn't install it.

Looks like I'll be buying a plug and a tube for my car.

[Cactuar]

Changed the differential oil yesterday. Not a difficult job but the smell of the fluid is not very nice, and it was tedious having to use a garden sprayer to pump the fluid inside the fill port (cheap DIY method). In the end I filled almost 2 liters of fluid, 75w140 LSD fluid in this case.

One note for those who want to change their diff fluid: you will need a stubby 14mm hex bit socket, to remove the fill plug. There is not enough room for a regular size bit. I had bought a regular 14mm hex bit in 1/2 size and there was no way to fit a ratchet in there. In the end I bought a stubby bit in 3/8 size and that worked fine.

Do not use this:
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Use this instead:
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[Cactuar]

So today was oxygen sensor day in the Cactuar garage...

After dealing with rust and two snapped bolts at the rear muffler:
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I got the exhaust low enough to see the sensor. However, what tool do I need to remove it?
I tried getting a short adjustable wrench in there but there is not enough room, because of the angle of the hex part.

Do I need a special tool?

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[dannyzabolotny]

I have a set of oxygen sensor wrenches, they're very helpful for tight spaces like that. This is the set I bought a little while back: https://www.amazon.com/CARTMAN-Autom...gateway&sr=8-4

Very handy for modern BMW engines as well, particularly the N63.

[theBMWbeast]

You need an o2 sensor socket. Most auto parts stores will loan them out if you don’t want to buy it.

[Cactuar]

Thank you, I will get an O2 sensor socket!

[Cactuar]

Just wanted to report quickly that I got the sensor out using this Tekton O2 sensor tool. Thanks for the advice guys

How critical is the torque spec on the sensor? I only have a 1/2 torque wrench and I can't get it to click due to the small rotation angle (cramped space).

It's on there pretty tight at the moment though, is that good enough?

[shogun]

That is enough, no need for a torque wrench. Bentley repair manual says on page 180-4: oxygen sensor to exhaust system 55 Nm (41 ft-lb)

[Cactuar]

Yes that's the value I was attempting to reach with my torque wrench. I will leave it alone then, thanks Shogun!

[Cactuar]

So the O2 sensor replacement went well. I got scared at first because I saw smoke coming from where the sensor screws in. After a while it went away. It's probably the PB Blaster that was burning off, because I sprayed a ton of the product there.

I also replaced the coolant temperature sensor (blue connector) for a new Bosch unit.

Then I changed the paper gasket between the throttle body and the intake manifold. The original gasket was covered in oil and was very dry and cracking.

These were all good items to change after 26 years (all the parts were original) but unfortunately they didn't fix my rough idle.

I checked all the intake hoses (only by feel for the two hoses under the intake manifold, I have small hands) but they were all in good shape, soft and without cracks.
Guess the next step is to get a smoke test. I hate having to bring my car to a mechanic, but I have no choice in this case.

[theBMWbeast]

They have little smoke test machines on eBay if you wanna do it yourself. ~$50. All you need for it to work is a compressor. I have one, works well, found a few leaks I really couldn’t see elsewise.

[kce1900]

shogun recommended this procedure:
https://www.youtube.com/watch?v=AsgB9eBl58I
https://www.youtube.com/watch?v=uZKZQNo5wpY
I bought the pump, but haven't tried it yet.

[Cactuar]

I will get the mechanic to do the smoke test, because I also want to get my fuel pressure regulator tested at the same time.

Today I worked on changing the transmission fluid. I got as far as draining the fluid and removing and cleaning the pan.

However when I attempted to remove the three torx bolts holding the strainer, two of them stripped! One came out OK with a T25 bit.

The T25 feels just a tad loose in the bolt head, so I wonder if I need to get a T27 bit. Can someone confirm if the strainer bolts are T25 or T27??

I really wish the Bentley manual would list the size of the fasteners, it would save some headaches!

Edit: I think the bolts are indeed T25 but my torx bit is poorly machined and cheap quality. It came in my basic tool set from a common store so probably not the best quality.

[Cactuar]

Success, the strainer is out! A member here said he hammered the next largest torx bit into the bolt to get it out, and that worked great.
I will be ordering three new metric bolts to replace the torx nonsense.

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Now I am facing a dilemma with the filter O-ring. All three O-rings I have are different.

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This seems like a common occurrence according to Shogun here, lots of aftermarket filters get the size of the O-ring wrong.

This is where the original BMW part will be crucial I think. I will order 24311218570 to be on the safe side.

[Cactuar]

I bought a fluid transfer pump to add to my toolbox (used a garden sprayer for diff oil last time and it wasn't fun).
At the same time I thought I would do a smoke test using a cigar.

The test worked well, except I only had small cigars on hand and they didn't make a lot of smoke. Anyway, there was no trace of smoke at all in the engine bay!?
I even tried pushing a bit of air using a compressor (low pressure) to force the smoke but it only came out of the exhaust pipes.

I'm stumped, because I was certain I had an exhaust leak with the way my idle revs up and down.

Any suggestions for other places to look? Should I get a real smoke test done with more smoke volume?

[CroughtonE32]

Whenever I feel like reading a little, I sit down at the desktop and skim over Shogun's blog and fix its, and TIM's page. Tim has this thing called a "Magic Reset". I've never had to do it, but the one page of reading makes me think it might be fun to set my ECU back to the day it came off the line. Tim explains it great here. Basically, removing from the ECU all the driving habits etc that it has learned over the years. I guess it's a (well, nothing seems to work so why not give this a try). Could be people would say not to do it, but give it a read. If anything it's a very interesting page from Tim's site.

https://www.meeknet.co.uk/E32/Reset.htm

[Cactuar]

Thanks Jeff, I read about the magic reset before (I also read during bouts of insomnia!).

Elsewhere I read that unbolting the negative battery terminal under the rear seat does the same thing.
I've tried that when I replaced the O2 sensor in August but it didn't change anything to the car. Same behavior as before, no initialization period or anything.

I should try this method, by draining the circuits of the car. Good idea.

I'm still waiting for the transmission filter O ring I ordered from the dealer.
When the transmission is bolted back together and working I'll try the magic reset.

Btw, I've had the transmission pan off the car for two weeks now while waiting for parts. I measured the oil that drained: 6 liters! That's twice the typical amount of a drain and fill (3 liters). The full capacity with torque converter is 7.5 liters, so this ATF change will be more thorough that I anticipated.

[shogun]

that is also sometimes called the magic shogun reset
Actually someone found that out on the German forum back in 2004 and I translated that and posted it on then active RF E32 forum and the name was born: back in 2004....Thanks, Shogun... I would have never thought... Roadfly ...Apr 6, 2004 ... tell you - black magic or not - the "full reset" procedure worked wonders for my car! ... Shogun, somebody's on to something - believe it or not! ....
Then I added it to my website: SHOGUN RESET Procedure & Testimonial http://twrite.org/shogunnew/fixes/controlsystems.html

once found that in an old TIS in German language:
In jedem Steuergeraet sind bestimmte Mittelwerte gespeichert, die die Grundwerte darstellen. Das Steuergeraet erhaelt je nach Motorzustand unterschiedliche Eingangswerte. Das lernfaehige System vergleicht die Eingangswerte mit den abgespeicherten Grundwerten und bildet dazugehoerige Stellbefehle. Die Stellbefehle werden an die entsprechenden Stellglieder weitergeleitet.
Wird das DME Steuergeraet fuer einen laengeren Zeitraum - ueber eine Stunde- stromlos, dann verliert das lernfaehige System die gespeicherten Werte. Bei Wiederinbetriebnahme eines geloeschten oder bei Einbau eines neuen Steuergeraetes muss sich das lernfaehige System die Eingangswerte des zugehoerigen Motors als neue Grundwerte selbst einlesen und abspeichern. Dieser Vorgang kann nach dem Starten zu unrundem Motorleerlauf und Stoerungen im Schiebebetrieb fuehren. Je nach Motorbeschaffenheit kann es einige Zeit dauern, bis alle Werte mit dem Motorzustand abgeglichen sind. Deshalb folgende Vorgehensweise beachten, bevor der Austausch beziehungsweise Wiedereinbau eines DME/DDE-Steuergeraetes vorgenommen wird:
1. Den Motor, wenn moeglich, vor Austausch des Steuergeraetes auf Betriebstemperatur bringen.
2. Das Steuergeraet ausbauen, das neue Steuergeraet einbauen und das Fahrzeug mit wechselnden Drehzahlen fahren.

google translate
Each control unit stores certain averages representing the basic values. The control unit receives different input values ​​depending on the engine condition. The adaptive system compares the input values ​​with the stored basic values ​​and forms associated control commands. The setting commands are forwarded to the corresponding actuators.
If the DME control unit is de-energized for more than one hour, the learning system loses the stored values. When restarting a deleted or when installing a new control unit, the learning system must read in and store the input values ​​of the associated motor as new basic values. After starting, this process can result in rough / unstable idling and faults in stop and go mode. Depending on the nature of the engine, it may take some time for all values ​​to match the engine condition. Therefore, observe the following procedure before replacing or reinstalling a DME / DDE control unit:
1. If possible, bring the engine to operating temperature before replacing the control unit.
2. Remove the control unit, install the new control unit and drive the vehicle at varying RPM

[Cactuar]

Thanks Shogun. I will definitely do the reset.

Today I installed the transmission filter on my 4HP22, using a new O ring from BMW.

I was wondering how can I be sure that the O ring is seated correctly in the opening of the transmission, and that the tube is aligned properly?
I went by feel and screwed the bolts slowly until they seated to the filter, but it wasn't possible to see actually if the filter is seating correctly.

Is there a way to know for sure or is it a case of if it's bolted, it will be guided automatically in the right place? Maybe I'm thinking too hard

[Cactuar]

Today I filled up the transmission with 6 liters of Castrol Transmax Dex/Merc ATF. I ran through all the gears and it seemed ok, so I went for a drive around the block.

The shifts are smoother now, especially 1-2 and 2-3. I still felt a bit of roughness during one 1-2 shift. Maybe a reset will fix it, if not probably a valve body cleanup will solve it.

How do I tell the temperature of the ATF without special equipment? Is there a way to get the OBC to display it?
At the moment the fluid level goes beyond the Max line, almost to the metal rod.
I definitely drained 6L+ of fluid and put back 6L, so don't know why it's so high.

[a777fan]

An infrared thermometer pointed at the bottom of the trans pan is pretty effective here. Relatively affordable on amazon these days too.


Sent from my iPhone using Tapatalk

[Cactuar]

I see they are affordable yes, thanks for the tip. I previously searched for them on Napa's website and they were 1000$+. I probably used the wrong search terms.

Forgot to post a pic of the new exhaust hangers installed. The exhaust now fits tighter inside the bumper cut out.
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[Cactuar]

The first gear exhibits a sort of whine, is it safe to assume this would go away when I change the 25 year old ATF?

So a year later the noise at low speed can still be heard. Even though I changed the engine oil, transmission fluid and filter, differential oil, it still happens.

Does anyone know what could cause this? It sounds like it's coming from the front half of the car, near the gear selection lever.

[MKIVJZA80]

can't listen right now, but if it's not an internal issue in the transmission, it could be driveshaft related. namely the center support bearing.