Help Me Sort This M30B35 Engine Harness

ClayW

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I need help Identifying which plug does what on this engine harness for an M30B35. Unfortunately, I didn't pull it, so nothing is labelled.

Here's what I've got so far:
1 - Tank vent
5 - O2 Sensor
8 - DME
10 - 12V Battery Power
17 - TPS
22 - AFM


11 & 12 are obviously relays, but I'm not sure which one is which, so I don't know which relays to get.

Thanks in advance.

M30B35Harness.jpg
 

HB Chris

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The color of the wire and type of connector plug will help determine where they go. The relays on a b35 are for the ecu and the fuel pump. There are basically seven wires that connect to the chassis harness which you can splice in next to the brake booster. On my harness I removed the diagnostic plug and it’s wires. I can provide some pics if needed.

Chris
 

BuzzBomb

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1 - Purge valve - It's use depends on what intake manifold you intend to use. If you are want to use the original L-Jet logs, just cut it off.
2,3 - Starter Solenoid - You only need the black w/ yellow striped wire which is your starter trigger.
4 - Connector to the ALT sub harness. If you don't have that harness, you'll need to run a +12 to the ALT from the starter +12 pole, and pick up the blue (CHG light) wire to connect to the engine bay harness (cluster)
5 - O2 Sensor
6 - Oil Pressure (You'll need a oil pressure sender with a Bosch connection)
7 - Idle Control Valve
8 - DME (179)
9 - DME compartment fan (not used)
10 - 12V Battery Power
11 - Fuel Pump Relay (Orange)
12 - Main Relay (white)
13,14 - Grounds for DME
15 - Coil +
16 - Coil -
17 - TPS (You only need three of the wires in that connection if you want to replace the Auto TPS with an original style one)
18 - Thermo-Time Switch (Blue plastic sender in the thermostat housing)
19 - Temp Sender (You'll only use one of the wires and connect it to your original spade connector temp sender)
20 - Crank Position Sensor (Motronic 1.3)
21 - #6 Spark Plug Wire Pickup (Motronic 1.3 )
22 - AFM (Motronic 1.0-1.3)
 
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BuzzBomb

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If I can further help with sorting your harness or its connections to the E9 engine harness, feel free to move this to private messaging.
 

ClayW

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1 - Purge valve - It's use depends on what intake manifold you intend to use. If you are want to use the original L-Jet logs, just cut it off.
2,3 - Starter Solenoid - You only need the black w/ yellow striped wire which is your starter trigger.
4 - Connector to the ALT sub harness. If you don't have that harness, you'll need to run a +12 to the ALT from the starter +12 pole, and pick up the blue (CHG light) wire to connect to the engine bay harness (cluster)
5 - O2 Sensor
6 - Oil Pressure (You'll need a oil pressure sender with a Bosch connection)
7 - Idle Control Valve
8 - DME (179)
9 - DME compartment fan (not used)
10 - 12V Battery Power
11 - Fuel Pump Relay (Orange)
12 - Main Relay (white)
13,14 - Grounds for DME
15 - Coil +
16 - Coil -
17 - TPS (You only need three of the wires in that connection if you want to replace the Auto TPS with an original style one)
18 - Thermo-Time Switch (Blue plastic sender in the thermostat housing)
19 - Temp Sender (You'll only use one of the wires and connect it to your original spade connector temp sender)
20 - Crank Position Sensor (Motronic 1.3)
21 - #6 Spark Plug Wire Pickup (Motronic 1.3 )
22 - AFM (Motronic 1.0-1.3)
Thank you!
 

Ohmess

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If I can further help with sorting your harness or its connections to the E9 engine harness, feel free to move this to private messaging.
Keep it here. These threads are golden to someone who runs into this problem in the future.
 

BuzzBomb

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Also, there are a lot of redundant wires in that B35 harness, especially the Auto fitted harness. If you want an more period look, you can pare it down to half it's size by using only what you actually need and re-wrap it.
 

teahead

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Curious if the diagnostic connector is of any use. If absolutely zero, then would be cleaner if it was rewired to remove it
 

BuzzBomb

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In an E9, since there is no check engine light or service interval, the only thing it could be used for is a remote starter trigger but it’s so unlikely that you would ever use it that it’s better to just remove it in most cases.
 

BuzzBomb

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Do you have the pinout for the X20 connector, and the necessary wiring for it?
Since most of the people that I've done this for wanted a more period look, also because there are far more wires in that harness than is really necessary, that 20 pin connector usually ends up in the trash. If you do trash the 20 pin connector, it's a good idea to use a removable connection to the engine (Weather Pack)
Simplified wiring, (chassis color to 1.3 color)
Alternator
Blue to blue
Coil power
Green to green
Oil pressure
Brown/green to green/brown
Starter
Black (large gauge) to black/yellow
Temp gauge
Brown/white to brown/yellow
Tach
Black (small gauge) to black
Fuel pump
Green/violet to green/violet – If not native, a new wire ran to new rear pump
 

ClayW

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couple questions:

1. The Coil Power wire just needs “key ON” power, correct?

2. The Temp Sensor wire only needs to be hooked up if I’m running the Temp Sensor through this harness, right? (I prefer to run it separately—just want to confirm that I don’t need to us the harness wire.)

3. How do I remove the diagnostic plug? Just cut out all the wires connected to it?
 

BuzzBomb

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couple questions:

1. The Coil Power wire just needs “key ON” power, correct?
Yes, fused. Might as well use the green wire that is already there for that?

2. The Temp Sensor wire only needs to be hooked up if I’m running the Temp Sensor through this harness, right? (I prefer to run it separately—just want to confirm that I don’t need to us the harness wire.)
Correct.
3. How do I remove the diagnostic plug? Just cut out all the wires connected to it?
Which plug- The one original to the car of the one on the 1.3 harness?
You wont need either. Without knowing how deep you're going as far as the engine bay harnesses, most of the loom forward of the connections that you'll be making near the firewall between the 1.3 and the original harness can be removed, including the original diag plug. The 1.3 diag plug will be redundant and can be removed. Honestly, if you are not afraid of getting dirty, lay the 1.3 harness out, unwrap it, and just use what you need. It will be half its size in the end. Plus, you can replace all the injector sockets with quick disconnects, which is well worth your time.
 

Markos

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Good point, but understand the info there is great for understanding the 1.3 harness, specifically the 20 pin connector's pin-outs, but it won't help with connections to anything before 1982.
Good point. I hadn't considered that the e28 site wouldn't have much information on e9-specific swaps.
 

BuzzBomb

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For those of you out there considering this conversion but find it easier going with written instructions, I put together a simple and short info sheet, compiled with info found on this site, the big blue book, and personal experience. Hope this helps.

E9 Motronic 1.3 Wiring Steps
Remove tape at harness from firewall towards front of car 18"
Note the separate black plastic harness with 5 wires.
2 SW (starter)
BN/GN (oil pressure)
SW/RD (cranking power to coil)
GN/WS (power to carbs)
Cut the plastic harness leaving 1' of lead from firewall.
GN/WS gets removed from fuse box inside of car.
SW gets connected to SW/GE starter solenoid
BN/GN gets connected to oil pressure
SW/RD is removed from the car.
SW wire going to diagnostic plug is removed entirely.
From the body harness leading to fuse box,
BU wire is charge light in dash (red L lamp)
Small SW is tach
BN/WS is temp gauge
Large GN is coil
GN/VI is fuel pump (CSI)
All remaining body and engine harness wires gets removed.
 
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ClayW

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When removing the diagnostic plug from the 1.3 harness, can I just cut out all the wiring connected to it, or do I have to leave anything?
 

BuzzBomb

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When removing the diagnostic plug from the 1.3 harness, can I just cut out all the wiring connected to it, or do I have to leave anything?
At this point, you need to crack a book and do the research. I put the time in already learning what to do, you can too. Everything in this thread, including references, will tell you everything you need to know.
 
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