SOLVED 1981 M30B32 Motronic 1.0 start issue.

E28 technical advice asked and given! Troubleshooting, modifications and more.
chrome75
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SOLVED 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

Hi ALL,

my apologies for posting questions regarding an engine conversion in a E3 on the E28 forum.
But I guess that the engine that I have in my E3 is/could be the same/similar to a 533i?



Car: Originally 2500 with carbs (E3) with manual transmission.
Engine: M30B32 Motronic 1.0, originally from a 1981 733i (E23) with automatic transmission.

Engine is dropped in to the E3 paired with the manual transmission.

All the wiring is connected properly to my best knowledge, I get fuel, no spark.


I have gone thru the steps described @ https://www.hpsimotorsports.com/motronic- related to ignition.



Anybody that possibly have a 1981 733i EUR ETM (Electrical Troubleshooting Manual)?
I guess that a 1981 533i (if there is one..), or a 1981 633Csi ETM could work as well.


Thanks a lot!

Bo
Last edited by chrome75 on Dec 29, 2022 4:38 AM, edited 1 time in total.
RonW
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by RonW »

I know the 535i has an issue with the ignition control transistor in the ECU. I don't know if other Motronic ECUs have the same problem.

But here's a link: ECU Repair and Chip Install.
Mike W.
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by Mike W. »

Some wiring diagrams are here, http://wedophones.com/BMWManualsLead.htm

However the first thing I see is the Motronic/Transmission relationship. M1.0, M1.0a, used sensors that went into the bellhousing to read both the flywheel teeth and an insert on the flywheel that was not present on pre motronic engines. That told the motronic ECU both what cylinder was where and when, and when after that to fire both the injectors and ignition. So you would need both a motronic flywheel and bellhousing to install the sensors into. Getrag 4 speed and 5 speed bellhousings are the same, but not the ZF 4 speed which at least some of the early cars came with, like mine.

Converting a carb'd E3 to L jet is much easier, I did that myself back in the 90's sometime. It was a great upgrade at least from the carbs we got here, which may be somewhat different than what you got, driveability was 1000% better although both fuel economy and torque were off some.

It might end up being easier to just use the carbs, there is an adapter to use a motronic camshaft with a conventional distributor.
chrome75
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

Ron, thanks for the link I will definitely look in to that. I'm not 100% comfy with doing things internally to the ECU but I guess that i need to learn. Bo
chrome75
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

Mike, good point for sure.

I managed to get the correct flywheel with a pin for the "position/reference sensor", also a the correct bell housing. I have recently checked and the pin is still there.
I measured both sensor and they came out fine, Position/ref. sensor = 950 ohm (between terminal 1 & 2), and Speed sensor = 979 ohm (between terminal 1 & 2).

I have been struggling with the "main relay", it has been difficult to understand what might be the correct main.
My conclusion is that a Bosch 0 986 AH0 602 should be the correct one, It's a 5 pin relay with a 30, 86, 87 & 87 b, 85.

I did secure the "green" cable that comes from the loom to the 3 pin outs (next to the ECU connector) that connects to the OBC. I connected the "green" to the ignition switch and it activates the main relay port 86. When that was done I got the main to "click"!


My first thought was to convert the carbs to injection, but i got a fully functional M30B32 and I went for that. After the car was in the hands of a few "experts" that obviously didn't manage to resolve the issue i got all fed up and decide to do it my self!

Wedophones have been helpful to a certain extent, but the info differs between 1982 735i and mine. The pin outs on my 35-pin ECU connector is different, color of the cables are different...
So a 1981 733i EUR ETM would be GREAT help!

Bo
Mike W.
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by Mike W. »

I don't know where to find the wiring diagram for that, we're obviously a US centric board so our references are biased towards that.

The first thing is probably insulting, so my apologies in advance, but I've seen it before more than once. Swap the speed and reference sensor connections up on the intake manifold. It's the same connector so easy to get switched. If it doesn't start, switch it back, don't forget.

Then assuming it's not the problem. The main relay you have sounds correct, it should have either two 87 terminals or an 87 and an 87b, which yours does. Technically they're different, but they do the same thing. The main relay, befitting it's name, does two things, it supplies power to the fuel pump relay coil, which in turn is actually turned on by the Motronic ECU, and supplies power to the Motronic ECU itself to run it. I think of it as one terminal controls fuel and the other controls spark. That's an oversimplification, but the way I think of it. Then start tracing wires. BMW usually uses the same color wires for the same thing even if they are in a different place. So you should have a black wire running from the plug going to the Motronic ECU to the coil. A medium thick wire, a 2.5 according to the diagram. And you should have 12 volts going to the coil to terminal 15 on a green wire.

Now I'm reaching a bit here, but if you have 12V to the coil on the green wire, you should be able to remove the black wire, then briefly connect that terminal to ground and get a spark. Remove the coil to distributor cap to test that, but it would provide a test of the coil and power to it. As I said, I'm reaching a bit, that would work on earlier cars and it appears it should work on Motronic, but I haven't tested it.
chrome75
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Location: Netherlands

Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

I'm very thankful for you guys taking the time to help!!

I know that US specs/information could be different in some aspects, still it gives an indication, and honestly US forums are SO much better than what we got.

Absolutely not insulting in any way. I have switched connections at the top (at the engine), I have visually inspected the sensors at the bell housing, switched their positions matching the upper connectors, still no change.
But I know that i'm in the neighborhood of finding that very little thing giving me the headache...... :)

I do have 12 V at port 15 (+) at the coil with "ignition on" supplied by the green wire. I also get 12 V at the ECU (pin out #1) coming from the coil (-) supplied by the black wire with "ignition on". So that's cleared out.
I will give it a try to check the coil with ground elsewhere to check for spark.

I will also post what the pin outs on my 35-pin are and how they react currently with Ignition OFF & Ignition ON. Being so that I have the first gen Motronic i don't have constant 12 V in to the ECU due to NO memory.

Once again THANKS a lot for ALL the help!

Bo
downforce22
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by downforce22 »

I have a motronic 1.0 e30 with 35 pin 073 ecu that i converted to M1.3. Mine was a manual already, but from what I have seen, there is a wire to prevent the car from starting unless in neutral on the M1.3 cars.

Maybe your ecu has a wire that is preventing this? The e30s call it the Neutral Safety Switch

1. Bypassing the neutral safety switch:

- Neutral Safety Switch
The NSS is built into the automatic shifter, and sends signals to a starter relay. The purpose of this design is so that you can only start the car in Park or Neutral. Bypassing the circuit is easy. Remove the kick panel above the driver's feet. There is a glob of wires and connectors that hangs on the lower end of the steering column. Push in the tabs to and slide the connectors out, off of the steering column.
https://www.bimmerforums.com/forum/show ... ranny-Swap
chrome75
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

downforce22, spot on.

This Neutral Safety Switch has been bugging my thoughts for sure. There is information on how to skip/by pass the NSS if the car has it originally. But my car doesn't have this due to no ECU originally. Now getting the information on whether the ECU (Motoronic 1.0) requires a signal from the NSS in order to e.g. give spark is unclear. Also If that is the case what pin out it might be?

What year is your E30? Do you have the information on your original 35-pin pin outs and where they go? I'm just curios because if your car is first years of the 80's it could be similar to mine...

I will try to post the information on mine during the day.

Br Bo
chrome75
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Location: Netherlands

Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

MY Motronic 1.0 35 pin connector

pin function cable
1. Ignition Timing Control (coil output) -BLK
2. Closed Throttle Input -WHT
3. Wide Open Throttle Input -WHT
4. Start Engine Input -BLK/YEL
5. Ground -BRN
6. AFM ground -WHT
7. AFM signal (input) -WHT
8. Crank speed sensor (1) -BLK
9. AFM signal (reference output) -WHT
10. Automatic -WHT
11. Fuel Rate Output -WHT
12. Empty
13. Coolant temp (input) -WHT
14. Fuel Injector Control 1,2,3 -WHT
15. Fuel Injector Control 4,5,6 -WHT
16. Ground -BRN
17. Ground -BRN
18. Empty
19. Ground -BRN
20. Fuel Pump Relay Control -WHT
21. Empty
22. AFM temp sensor (input) -WHT
23. Ground -BRN
24. Empty
25. Crank position sensor (1) -YEL
26. Crank position sensor (2) -BLK
27. Crank speed sensor (2) -YEL
28. Empty
29. A/C “on” (input) -WHT
30. Injector/fuel related (?) -WHT
31. Injector/fuel related (?) -WHT
32. Injector/fuel related (?) -WHT
33. Injector/fuel related (?) -WHT
34. Empty
35. Ground -BRN

+ the 3 pin outs from the loom that goes to the OBC (WHT, GRN, BLK).


When "Ignition OFF" i get NO signal on any of the 35 pins (0 Volt)
When "Ignition ON" I get the following signals:

pin function cable
1. Ignition Timing Control (coil output) -BLK => 12 V

3. Wide Open Throttle Input -WHT => 5 V

9. AFM signal (reference output) -WHT 12 V
10. Automatic -WHT => 12 V

13. Coolant temp (input) -WHT => 5 V
14. Fuel Injector Control 1,2,3 -WHT => 12 V
15. Fuel Injector Control 4,5,6 -WHT => 12 V

20. Fuel Pump Relay Control -WHT => 12 V

22. AFM temp sensor (input) -WHT => 5 V

25. Crank position sensor (1) -YEL => 1.1 V
26. Crank position sensor (2) -BLK => 1.1 V
27. Crank speed sensor (2) -YEL => 1.1 V

29. A/C “on” (input) -WHT => 12 V
30. Injector/fuel related (?) -WHT => 12 V
31. Injector/fuel related (?) -WHT => 12 V
32. Injector/fuel related (?) -WHT => 12 V
33. Injector/fuel related (?) -WHT => 12 V


+ the 3 pin outs from the loom that goes to the OBC (WHT, GRN => 12 V, BLK => 12 V).

Any thoughts? Do I have signals at the correct places or not? Do I miss any signals?

Bo
JohnH
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by JohnH »

The official Schaltplane are available at https://bmw-grouparchiv.de/ for free download.

Select Search, then Keyword Search and fill out the search page as follows;

Please select a keyword catalog: Type of archival document

Alphabetical display: schaltplane

Selected search criteria: Workshop literature, Vehicle electrics / electronics

and then press the search button, which with a bit of luck will give you a list of the documents available. Click on the picture, and then you can download the manual.

Hope that helps a bit.
tschultz
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by tschultz »

If your car is an '81, does your cluster have the fuel rate/consumption gauge? I wasn't sure that 1981 models had this. If you do, I think you also have the OBC which would have the lockout code feature. If you car is early and doesn't have these features, then you likely don't have the lock out feature.

The difference is like the E12 vs E28 difference of interior and cluster layout.

Early style Image

I am just thinking back to my knowledge of the 1981 635 models which used motronic M90. It is motronic so should follow the normal wiring layout, but no lock out feature. The reason I suggest no lock out with no OBC is because I did a M1.0 to M1.3 swap and the early model didn't have OBC or this wire in the C103 of the glovebox.

I could get my car to start but it would not move off idle. Being a euro car, it did not have o2 sensor feedback. My suspicion is that the automatic flywheel pick--n came off and it would not rev properly. Turned out the euro ECU and wiring was NOT the same a US based cars of the same year.

Have you already converted the C101 fusebox connector to match the engine? Not sure if '81 E23 had spade style connector, but I would guess it might be plug and play with E3 fusebox.
Worth checking if the coil is getting 12v during cranking and try to diagnose by following the flow of power to the spark plugs.
chrome75
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

Thanks John!

Very valuable information. I have done some searches but I will definitely continue, it seems like this is a very good direction to get information.

Bo
chrome75
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Location: Netherlands

Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

tschultz,

my car is a -76 E3 with no such thing as fuel rate/consumption gauge or OBC.

Unfortunately i don't know what "lock out" or C103 is?
Is it the function that the OBC have with a code in e.g. E24's?
If that is what you are referring to I guess that you are talking about the connector next to the ECU main connector. It's a 3-pin connector with a green, white and black wire that usually goes to the OBC. Being so that I don't have an OBC i connected the green wire directly to the ignition switch. When I did that i got the main relay to "click".
3-pin:
-Green connected to main relay port 86.
-White connected to ECU pin out #11 (Fuel gauge)
-Black connected to ECU pin out #1 (coil output)


I didn't do the connection at the fuse box. I will try to check that, as it is right now there are some cables loose from the engine wiring harness, don't really know what they are... What seems to be connected is at least ignition switch, I get 12 V at the coil, i get the starter to run.

Good point to check if the coil gets 12 V while cranking, have not done that.

Bo
pappentl
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by pappentl »

I installed an M30B34 in my 1981 528i, converting from L-jet to an e28 535i engine harness and '059 Motronic I had lying around. Other than defeating the automatic lockout (also switched to a 5-speed) it was plug and play. I only had to feed power into the ECU and fuel pump relay, IIRC. I made a jumper from the e28 engine harness plug to the old style e12 plug at the fuse box. I can look at the connections if you'd like. The only issue with the whole install was making sure I had good grounds.
chrome75
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Location: Netherlands

Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

@JohnH

You ACED it!

Got the info for my 1981 733i EUR from the archives. SO DARN HAPPY!!!!

Bo
chrome75
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Location: Netherlands

Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

pappentl,

if I understand correctly you had an auto in your E12 from the start?
Would be great if you could look at the connections!

I need to check my grounds, it's actually one thing that I haven't done yet.

Bo
JohnH
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by JohnH »

chrome75 wrote: Aug 15, 2020 6:30 PM @JohnH

You ACED it!

Got the info for my 1981 733i EUR from the archives. SO DARN HAPPY!!!!

Bo
Bo

Pleased to help. Band (Volume) 4 , Seite (Page ) 2.1 ?

Regards
John.
chrome75
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Location: Netherlands

Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

JohnH wrote: Aug 15, 2020 11:37 PM
chrome75 wrote: Aug 15, 2020 6:30 PM @JohnH

You ACED it!

Got the info for my 1981 733i EUR from the archives. SO DARN HAPPY!!!!

Bo
Bo

Pleased to help. Band (Volume) 4 , Seite (Page ) 2.1 ?

Regards
John.
John,

Band (Volume) 4, Seite (Page) 2.4 "Erläuterungen zum Schaltplan digitale Motorelektronik ab Modell 81.

First ever information that confirms the pin outs on my ECU.

Bo
chrome75
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Location: Netherlands

Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

tschultz wrote: Aug 14, 2020 9:52 AM
Worth checking if the coil is getting 12v during cranking and try to diagnose by following the flow of power to the spark plugs.
Coil port #15 (+):
Ignition off = 0V
Ignition on = 12V
Cranking = 9.3 V

I get signal while cranking but is to low?
chrome75
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Location: Netherlands

Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

Gents,

bit curious if any of you can determine if the situation seems normal or if I'm missing voltage or have wrong voltage somewhere...?
Also what function does port #10 Automatic have?

Conditions:
-Decent battery
-ECU connected
-Ignition off, Ignition on, crank

Pin function--------------------------------------------- Ign. OFF-------Ign. ON----------Crank

1. Ignition Timing Control (coil output)----------- 0 V-------------12 V---------------9.3 V
2. Closed Throttle Input----------------------------- 0 V--------------0 V----------------0.3 V
3. Wide Open Throttle Input------------------------ 0 V--------------5 V----------------5 V
4. Start Engine Input--------------------------------- 0 V--------------0 V----------------8.6 V
5. Ground
6. AFM ground----------------------------------------- 0 V--------------0 V----------------0.3 V
7. AFM signal (input)--------------------------------- 0 V--------------0 V----------------0.5 V
8. Crank speed sensor (1)----------------------------0 V--------------1.4 V--------------1.8 V
9. AFM signal (reference output)------------------- 0 V--------------12 V----------------8 V
10. Automatic------------------------------------------ 0 V--------------12 V---------------10 V
11. Fuel Rate Output--------------------------------- 0 V--------------0 V-----------------0 V
12. Empty
13. Coolant temp (input)---------------------------- 0 V--------------5 V-----------------3.9 V
14. Fuel Injector Control 4-------------------------- 0 V-------------12 V-----------------10 V
15. Fuel Injector Control 1-------------------------- 0 V-------------12 V-----------------10 V
16. Ground
17. Ground
18. Empty
19. Ground
20. Fuel Pump Relay Control------------------------ 0 V-------------12 V-----------------2 V
21. Empty
22. AFM temp sensor (input)------------------------ 0 V--------------5 V-----------------3.4 V
23. Ground
24. Empty
25. Crank position sensor (1)------------------------ 0 V--------------1.1 V---------------1.5 V
26. Crank position sensor (2)------------------------ 0 V--------------1.1 V---------------1.5 V
27. Crank speed sensor (2)-------------------------- 0 V--------------1.1 V---------------2 V
28. Empty
29. A/C “on” (input)--------------------------------- 0 V--------------12 V----------------10 V
30. Fuel Injector Control 5-------------------------- 0 V--------------12 V----------------10 V
31. Fuel Injector Control 6-------------------------- 0 V--------------12 V----------------10 V
32. Fuel Injector Control 3-------------------------- 0 V--------------12 V----------------10 V
33. Fuel Injector Control 2-------------------------- 0 V--------------12 V----------------10 V
34. Empty
35. Ground

+ the 3 pin outs from the loom that goes to the OBC

-WHT Connected to # 11------------------------ 0 V---------------0 V------------------0 V
-GRN Connected to # 86 Main Relay---------- 0 V---------------12 V-----------------9.3 V
-BLK Ignition Timing Control (coil output)-- 0 V---------------12 V-----------------9.3 V

Coil port #15 (+):
Ignition off = 0V
Ignition on = 12V
Cranking = 9.3 V


I still don't get any spark at the plug using spark plug wire. I have also tried directly from the coil, no spark.
JohnH
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by JohnH »

It would seem that you may have a duff (bad) coil.

This Russian site http://repair.bmw-e23.com/ has an online version of the official bmw repair manual.

1. Select Reparaturanleitung for the German language version or select Repair Manual for the English language version. I will select the English version.
2. This will give you the Important Notes screen. Select, Main Groups in the top right and this will take you to the Main Contents screen.
3. Select group 12 Engine Electrical (in Russian for some reason)
4. Select 12 13 009 Ignition coil - Checking
5. This outlines the test procedure as contained in another document called Nominal Values. Unfortunately they dont appear to have a copy of the Nominal Values document on this site. They do however have the specifications referred to in the Nominal Values document, and these can be found under section 12 00 00 - See specifications.
6. The important thing to note with this document is the the values differ for ECE, US and Japanese models so select which is appropriate on each page ( the red words).
7. You want page 2 where you will find values related to the various ignition coils. As you can see all the values differ, so its vital that you have the correct coil install for the ignition system that matched the DME that you are using. You did install the correct coil?

Bo, not trying to teach you to suck eggs, just trying to be thorough.

Hope this helps.
chrome75
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Location: Netherlands

Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

Thanks John!

I've never before heard the expression "suck eggs", i actually had to google it.... Hilarious!!!

Anyhow no worries at all, I think that the best approach is to be thorough as you say and exclude all the possible areas that could lead to an issue.

I just got a new aftermarket coil (and cable coil => distributor), I would say its a cheap one. Engine did work with an exact same type of aftermarket coil previously, not in my E3 though. I have measured the new AM coil and the old AM coil and I get the same values.
Between 15 (+) and (-) i get 2.8 Ohm
Between 15 (+) and HT i get 6300 Ohm

Bo
JohnH
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Re: 1981 M30B32 Motronic 1.0 start issue.

Post by JohnH »

OK, the coil should work, but you aren't getting a spark. Given that you have transplanted the engine and ignition system (which worked?), one has to assume that you missed something during the installation, so, no spark, because its not grounding?

Check for continuity between the engine and ground (battery negative terminal).

Its got to be something simple?
chrome75
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Joined: Aug 02, 2020 6:15 AM
Location: Netherlands

Re: 1981 M30B32 Motronic 1.0 start issue.

Post by chrome75 »

John, you have a great hit rate!

I have been very focused on checking ALL the areas that usually could be a problem. With that said I have also solved some issues such as main relay function, 12V to coil, and more signals to ECU.

Yesterday I started looking at things from scratch, this time looking at grounding points.

I cleaned the battery ground to chassis, I cleaned the ground engine mount to chassis (passenger side), started looking at the ground between cylinder head (cold side) and firewall... NOTHING!
So I guess not having a ground cyl. head/firewall could mean that when I ground the plug to the head it will not give spark...

I will try to fix that coming weekend!

If that is the issue it's pretty embarrassing.... :)

On what other positions on the engine could there be grounds?

Bo
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