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M90 Motronic 1.0 wiring diagram

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PV-ALPINA
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Joined: Tue Sep 11, 2012 8:02 am
Location: Sweden

M90 Motronic 1.0 wiring diagram

Post by PV-ALPINA » Tue Nov 24, 2015 2:30 pm

Hi,

I wonder if anyone has the wiring diagram for the Motronic based M90? The engine is from a 1981 635CSI with ECU 0 261 200 002 and AFM that ends with 013.
Johan Nordkvist
633CSIA 1977 Polaris
M635CSI 1984 Bronzit Beige
M635CSI 1985 Diamant Schwartz
635CSI (manual with catalyst) 1988 Diamant Schwartz

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Hefeweizen
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Post by Hefeweizen » Tue Nov 24, 2015 3:46 pm

Here, this may help
http://www.house-calls.us/Electrical

Good luck
Rainer
85 635CSi (Silver, Daily Driver)
79 633CSi (Red Euro, Project)

"If you think a good European mechanic is expensive, try a bad one!"

PV-ALPINA
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Joined: Tue Sep 11, 2012 8:02 am
Location: Sweden

M90 Motronic 1.0 wiring diagram

Post by PV-ALPINA » Tue Nov 24, 2015 4:04 pm

Hi,

This is unfortunately for the 633CSI with L-jetronic so it is not the same as M90 with Motronic 1.0. Euro 635 csi with M90 Engine and motronic was made for just one year late 80-early 82. and has a special wiring diagram. If anyone has the instruction manual for a Euro 635 csi from 1981 the wiring diagram should be printed at the end of that manual.
Johan Nordkvist
633CSIA 1977 Polaris
M635CSI 1984 Bronzit Beige
M635CSI 1985 Diamant Schwartz
635CSI (manual with catalyst) 1988 Diamant Schwartz

GRNSHRK
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paging Bert to the Shark Phone . . .

Post by GRNSHRK » Tue Nov 24, 2015 4:26 pm

PV, there is a gent named Bert Poliakoff (sp :-? ) on the board who is performing a complete resortation of an '81 Euro, ///M90 with Motronic 1.0 :-k

I would reach out to him if he doesn't respond to this thread, for sure he's got what you need =D>

:mrgreen:
:mrgreen:
Bobbo
1980 633 CSi
Cypress Green/Pearl Beige
2011 F10 528i
2005 E46 330 Ci ZHP Cabrio
Image

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GripGreg
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Post by GripGreg » Tue Nov 24, 2015 7:19 pm

Bobbo, or whomever; If my Buster has a build date of 9/81 with a motronic system,
and is a euro build, why do I have an M30 motor according to Realoem and not an M90? :-k Very interesting!
Why is Bert's an M90?
Is it possibly because of the change-over year? Did I answer my own question?
I found out the M90 is a better motor? Why?
Also, Realoem doesn't say if I have a 1.0 or a 1.3 system. Vin is 5592605
Thanx in advance,,,,Greg
Hit the apex
in Long Beach, Cal
Buster/'82Euro6 Build Date 9/81
Rosallina/'80 528i Build Date 4/80

GRNSHRK
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Good questions, related to the changeover . . .

Post by GRNSHRK » Tue Nov 24, 2015 9:12 pm

Yes Greg, confusing times for the E24 for sure #-o

Your 09/81 build date "should" make yours an MY82, which for US version 6ers is a real mish mash from the parts bin :roll:

Underneath you still have the E12 chassis, as well as the interior, AND still retains the vacuum boosted power brake system, but with the first version of Motronic, which I surmise would be V1.0 :-?

The US version '82 uses an M30B32 engine, low compression ratio, while the Euro versions (certainly the 635) was still running the infamous M90 =D>

So if your 6er is a 635, then it likely has an M90 as well [-o<

Why is the M90 considered "better" you ask :-k

Well, this short stroke "true" 3.5L engine shares the internal dimensions of the original M88 that was found in the ///M1, high revving and a torque monster, even in SOHC/12V trim :lol:

And I wouldn't hold too much credit in the REALOEM site indicating that you have an M30, as they are known to be not all that accurate [-X

I think you will find that ///M635 owners that run their VIN find that the site indicates that they have an S38, which of course is not true either :roll:

Hope this helps 8)

:mrgreen:
:mrgreen:
Bobbo
1980 633 CSi
Cypress Green/Pearl Beige
2011 F10 528i
2005 E46 330 Ci ZHP Cabrio
Image

You can never have too many BMW's

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Brucey
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Re: M90 Motronic 1.0 wiring diagram

Post by Brucey » Tue Nov 24, 2015 10:17 pm

PV-ALPINA wrote:Hi,

I wonder if anyone has the wiring diagram for the Motronic based M90? The engine is from a 1981 635CSI with ECU 0 261 200 002 and AFM that ends with 013.
The ECU pinouts are common with the other early motronic ECUs and although there are some detailed differences (eg in idle control) most of what you have is identical to the engine wiring of later (and more readily available) diagrams that relate to the 5/82 on motronic models.

Useful diagrams exist in the Haynes manuals for

-3/5series
- E12 5ers

The body wiring and stuff like electric fan wiring etc is identical to E12 stuff.

IIRC Ron has a blown-up wiring schematic from an '81 BTW, taken from the owners manual. It is accurate, but very poorly laid out. I don't say this often, but the diagrams in the Haynes manual were easier on the eye in this case.

If you want to know what is in the thermostat housing, this

viewtopic.php?t=15397&highlight=gubbins

should help

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

bpoliakoff
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Post by bpoliakoff » Tue Nov 24, 2015 11:19 pm

I have an 81 euro with the 002 ECU and 013 AFM i have the chassis wiring schematic for the car that was copied from a factory manuel. I had them copied on an extra large copy machine and they are blown up 130% In addition I have the “keyâ€
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.

GripGreg
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Post by GripGreg » Wed Nov 25, 2015 5:18 am

Thanx Guys! This is now more clear than it's ever been!
I have a Euro M90 3.5 with a Motronic 1.0.
On the intake side is a stamp 3.2/3.5.
I already knew of the E12 chassis and interior. WOW! Don't I know! :roll:
Thanx again,,,,Greg

Ps: Wait, Bobbo, you said the build date "should make mine an My82 which for US versions":
But, Buster was bought in Europe by a soldier and shipped to the
Bakersfield area upon discharge. :-k
Hit the apex
in Long Beach, Cal
Buster/'82Euro6 Build Date 9/81
Rosallina/'80 528i Build Date 4/80

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olympia57
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Re: M90 Motronic 1.0 wiring diagram

Post by olympia57 » Wed Nov 25, 2015 8:31 am

Brucey wrote:
PV-ALPINA wrote:Hi,

I wonder if anyone has the wiring diagram for the Motronic based M90? The engine is from a 1981 635CSI with ECU 0 261 200 002 and AFM that ends with 013.
The ECU pinouts are common with the other early motronic ECUs and although there are some detailed differences (eg in idle control) most of what you have is identical to the engine wiring of later (and more readily available) diagrams that relate to the 5/82 on motronic models.

Useful diagrams exist in the Haynes manuals for

-3/5series
- E12 5ers

The body wiring and stuff like electric fan wiring etc is identical to E12 stuff.

IIRC Ron has a blown-up wiring schematic from an '81 BTW, taken from the owners manual. It is accurate, but very poorly laid out. I don't say this often, but the diagrams in the Haynes manual were easier on the eye in this case.

If you want to know what is in the thermostat housing, this

viewtopic.php?t=15397&highlight=gubbins

should help

cheers

Ron gifted that laminated wiring schedule to me . I'd offer to copy and send it but it's a bit creased and faded and I'm not sure it would copy too well being laminated.
I also have the original wiring diagram that the above was copied from and that is in an early owners manual but you have to use a magnifying glass to follow it through.
Bert's offer seems the best solution.
Good luck.
1981 635 series 1

PV-ALPINA
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Location: Sweden

ecu

Post by PV-ALPINA » Wed Nov 25, 2015 9:09 am

Ok, thanks alot for your answers.

Then I have another question. Does anybody know if the ECU:s on motronic 1.0 are interchangable? I mean if you have a 002 ECU and 013 AFM can that be exchanged with a 011 ECU and its corresponding AFM or 043 ECU with corresponding AFM? All Motronic 1.0 do have the low resistance fuel injectors so that should not be the problem.

Since Motronic 1.0 do not have a removable chip(except for the M88 Engine with 055 ECU) there is few possibilities for tunig. However, I have figured out that Alpina B7 used a standard 0 261 200 043 box. The "only" differences compared to a NA engine is the turbocharger and the fuel injectors. Correct me if I am wrong, would it not be possible to just change the injectors on a motronic 1.0 to ones with higher flow capacity when tuning the engine? Lets say you know that a particular camshaft and headwork would give a power increase of 25%, by using injectors with 25% more flow capacity would solve that problem with the standard ECU, or?

/Johan
Johan Nordkvist
633CSIA 1977 Polaris
M635CSI 1984 Bronzit Beige
M635CSI 1985 Diamant Schwartz
635CSI (manual with catalyst) 1988 Diamant Schwartz

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Brucey
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Post by Brucey » Thu Nov 26, 2015 12:07 pm

you may find Bill Wolff's data (reproduced here; viewtopic.php?t=12218&postdays=0&postor ... f&start=30)

of use.

FWIW I suspect that a 008 ECU might do you; it has an O2 sensor input but I think (please correct me if I'm wrong) it defaults to open loop settings if the O2 sensor is unplugged. I am also told that the 008 is chippable.

I don't know anything about the 043 ECU, sorry!

All the ECUs that drive low impedance injectors work differently from those that drive high impedance injectors; the high impedance ones see a simple square pulse (so are closed by spring pressure) whereas the low impedance ones see both opening and closing pulses. If you drive LI injectors using an ecu meant for HI injectors, the output stage of the ECU will blow up at WOT. I have heard of people doing this (at idle, for a short time, where the duty cycle is short enough that the ECU won't so quickly fail) as a diagnostic test.

If you use HI injectors with an ecu meant for LI injectors, the current rating of the output stage is OK but load is considerably more inductive. The transients may overwhelm the voltage protection built into the output stage of the ECU. I have heard of people using this combination but I don't know how reliable it is.

A point of concern is that at some stage the way the AFM is calibrated changed completely; one version (the early one I think) uses a voltage output that is linear with flap angle and the other uses a voltage output that is linear with air mass flow. If you exchange the AFM for the wrong type the fuelling will go to pot on an open loop car.

Another variable is the WOT contact in the TPS; this closes at different angles according to the part number of the TPS. Once the WOT contact closes the AFM signal is bypassed and the sole fuelling (and ignition) determinants (for open loop and closed loop I think) are engine speed and temperature signals (coolant and air). Note the FPR will still regulate fuel pressure if the plenum is a partial vacuum (eg clogged air cleaner). the fuelling is set to be rich (normally a little too rich) at WOT, presumably to preserve the piston tops!

As you suggest, getting the engine's fuelling more or less correct is possible with a little jiggery-pokery; however this still leaves the vexed question of the ignition timing. On early motronic the inlet vacuum is effectively inferred from the AFM signal, and the AFM signal exerts a major influence on the ignition timing as a result.

Maybe that is a good way of doing it... but modern fuels often work better in these engines with a bit more ignition advance on part throttle. A common 'tweak' is to increase the AFM spring pressure a little, and also to decrease the fuel pressure slightly if the mixture goes too rich. This advances the ignition timing on part throttle and can improve matters in terms of midrange performance (torque and fuel economy); however it also eats into the margins at WOT so whilst a little less rich may be a good thing you can overdo it and there is a danger that the engine will run too lean at WOT. Note that stoichiometric at WOT is too lean really.

BTW since the 055 ECU (M635) has built in idle control and the external idle control in 002 etc ECUs is not 100% reliable, I have often wondered if a chipped 055 ECU would make a good substitute (with wiring changes to support the ICV drive).

hth

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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tschultz
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Re: M90 Motronic 1.0 wiring diagram

Post by tschultz » Tue Oct 02, 2018 9:54 pm

Turns out 008 Ecu is not compatible with '81 635's used to using the 002 ECU.

Working on converting my setup to 008 and US stuff, but am still working through it.

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