M30B35 Swap FAQ

[BuzzBomb]

Mhh... but how does the ECU know to adjust the idle when there is no signal from the A/C switch???

Judging by the schematics, I'm going to say that m1.3 ecu does use the a/c compressor signal as input at pin 40. So you can try connecting pin 4 of c103 to pin 40 of the ecu.

For a m1.3 ecu map go to the 1992 e34 ETM, section 1210.2 Digital Engine Electronics (DME M1.3, 6- Cylinder M30)

Actually both 40 and 41 are tied together and take their signal from the A/C switch power on wire. Just tie them together at the DME, pull the radio, and run a wire to the back of the A/C switch (pin 3, GN/Yl). Done.

[Sharkland]

Hi everybody !

I post from France, and I would like to thank you for all this stuff !
I've made the swap and your experience helped me a lot

I would like to add an info about the temp sender gauge :
Here is my car : An E24 which was a 628 CSi L-Jet and I put a M30B35 in it !


As my nickname says, in Sharkland there's a lot of BMW parts, and I so can test several possibilities
I tried a one-spade temp gauge (with the brown/violet) and it worked out well. Some pics to illustrate :



Test with hot water and seeing if someting hapens...


Seems okay !


Here's the gauge I used :




The two-spade gauges are used for the air-conditioned cars. In my E24 I use another temp gauge to start the airconditionng fan which replaces the visco fan cluch...

Once again thanks for all the info there !

Sharkland (from the south of France)

[BuzzBomb]

I tried a one-spade temp gauge (with the brown/violet) and it worked out well.
Here's the gauge I used :

Is this the original sender from your 628?

[Sharkland]

Hi !

No, the original was a two-spades gauge as the car had the airconditioning option. But temperature characteristics are the same...

The one I put on my E24 : one spade, from an early E24 or an E12 : 118°C


The same gauge but with two spades. Air-conditionned of the late 70's. 120°C


Always the same but for E24 since 05/1982 or E28... Bosch


The same in a 535i E34. VDO


There's no visual difference. Are they really different ?

[BuzzBomb]

Hi !

No, the original was a two-spades gauge as the car had the airconditioning option. But temperature characteristics are the same...

The same gauge but with two spades. Air-conditionned of the late 70's. 120°C

Just so you know, the sender in this picture has nothing to do with air conditioning in an e24. This larger body sender with two spades was an e24/e23 specific sender, because one spade sends a signal to the gauge, and one spade is for the temp warning indicator lamp in the cluster. The e23 uses this sender as part of the "Automatic" A/C system, but not the e24.

[geordi]

I've read and re-read this thread regarding the coolant temp sensor/coolant temp sender. I got totally confused and had to step back to make sure I really understood. Hopefully this will help others.

The B35 has two coolant temp thingies that are plugged into the thermostat housing.

Coolant Temp Sensor
This puppy feeds the ECU with info on the engine temp. It connects with two wires via a BLUE connector (at least on my E24 B35 harness). The wires that run to it are BR/RT and BR/OR. The BR/RT goes to pin 45 of the DME. BR/OR is ground.


Coolant Temp Sender
This goes to the instrument cluster and drives the temperature gauge. It connects with two wires via a BLACK connector. The wires that run to it are BR/VI and BR/GE (GE is yellow). On an E34 both wires go to the the cluster. It appears BR/GE is power and BR/VI is the sender.


The B34 has three thingies plugged into the thermostat housing: A Coolant Temp Sensor, Sender, and the Thermotime Swtich. The Thermotime Switch is not needed on the B35.

The B34 Sender has one wire (the B35 has two per above).

The E28 cluster has a BR/VI wire leading to it that feeds the temperature gauge. If you are using a B34 Sender, then the BR/VI wire from the harness (was going to pin 4 on the 20X connector) will go to the BR/WH wire at pin 4 of the C101.

This is super straight forward, so I'm not sure why others had temp gauges that didn't work. Maybe it's because they were using B35 Senders?

CEK,which part number did you to order the Coolant Temp Sensor and Coolant Temp Sender? I have an e24 harness and 1.3 ECU.
Anyone else feel free to chime in.
thanks

[tig]

CEK,which part number did you to order the Coolant Temp Sensor and Coolant Temp Sender? I have an e24 harness and 1.3 ECU.
Anyone else feel free to chime in.
thanks

Temperature sender to cluster 12621710512 use 88 528e(part number 12621710512 ) 

Engine temperature sensor to ECU 13621709966 same as m30b34 (part number 13621709966) 

At least that's what my spreadsheet says. I can't find the actual order/invoices. Sorry.

[geordi]

I've read and re-read this thread regarding the coolant temp sensor/coolant temp sender. I got totally confused and had to step back to make sure I really understood. Hopefully this will help others.

The B35 has two coolant temp thingies that are plugged into the thermostat housing.

Coolant Temp Sensor
This puppy feeds the ECU with info on the engine temp. It connects with two wires via a BLUE connector (at least on my E24 B35 harness). The wires that run to it are BR/RT and BR/OR. The BR/RT goes to pin 45 of the DME. BR/OR is ground.


Coolant Temp Sender
This goes to the instrument cluster and drives the temperature gauge. It connects with two wires via a BLACK connector. The wires that run to it are BR/VI and BR/GE (GE is yellow). On an E34 both wires go to the the cluster. It appears BR/GE is power and BR/VI is the sender.


The B34 has three thingies plugged into the thermostat housing: A Coolant Temp Sensor, Sender, and the Thermotime Swtich. The Thermotime Switch is not needed on the B35.

The B34 Sender has one wire (the B35 has two per above).

The E28 cluster has a BR/VI wire leading to it that feeds the temperature gauge. If you are using a B34 Sender, then the BR/VI wire from the harness (was going to pin 4 on the 20X connector) will go to the BR/WH wire at pin 4 of the C101.

This is super straight forward, so I'm not sure why others had temp gauges that didn't work. Maybe it's because they were using B35 Senders?

CEK,which part number did you to order the Coolant Temp Sensor and Coolant Temp Sender? I have an e24 harness and 1.3 ECU.
Anyone else feel free to chime in.
thanks

I received part number 12621710512 Temperature sender to cluster today (It is superseded by 12621710511). It has one spade on the sending unit, while my e24 6er harness has slots for two spades. So just to clarify; I am only using one slot on the harness and the other will not be used. The sender is grounded on the housing… correct?

[demetk]

How come you didn't get the sender with the two terminals so the warning light would also work?

[geordi]

How come you didn't get the sender with the two terminals so the warning light would also work?

Well that's kind of my problem… if I read the thread correctly, the recommended sender for the swap is part number 12621710512, (now superseded by 12621710511). What I found is #s 12621716137 and 13621709967. Realoem doesn't provide enough information to verify if they have two terminals. Yeah… this is confusing

[demetk]

What year e24? Here's the senders, #8 - Temperature sending unit/warning contact

http://bmwfans.info/parts-catalog/E24/U ... r_hoses_2/

I'm assuming the warning contact is the second terminal for the warning light on the gauge.

[BuzzBomb]

Harness is e24. Chassis is e28. No warning lamp.

[demetk]

Ok then, nevermind. The single terminal sender will work.

[geordi]

What year e24? Here's the senders, #8 - Temperature sending unit/warning contact

http://bmwfans.info/parts-catalog/E24/U ... r_hoses_2/

I'm assuming the warning contact is the second terminal for the warning light on the gauge.

88-89' e24 harness.

Thanks for the back up guys.

[tig]

[
Found this: http://www.seattlecircuit.com/fuel_signal.htm

Onboard Computer fuel signal correction
Restores complete accuracy after you install larger injectors


The fuel signal converter is designed to correct for larger than stock fuel injectors on most Bosch and Siemens equipped vehicles. The usual symptoms of installing larger fuel injectors is that your On Board Computer (OBC) will display inflated mileage and range information. This is due to the fact that the larger injectors require a shorter signal than the stock injectors to flow the same amount of fuel. Your OBC interprets the shorter fuel pulse as increased fuel economy.

The fuel signal converter digitally conditions the fuel signal to match the signal for your stock injectors. Your OBC will once again display accurate mileage and range information.

The circuit is simple to connect and requires only power, ground and a fuel signal as input. It is available in two versions: the original version that will work with factory ECU’s and the standalone version. The standalone version will bypass your ECU completely and read the fuel signal directly from a single injector. This is useful for Megasquirt, Autronic, MOTEC and other standalone ECU’s. It is extremely small, rugged and can be mounted almost anywhere.

It is fully adjustable for any injector upgrade and in most instances will reach accuracy exceeding +/- .2 mpg!

I might get one and see if it works.

Purveyor of these just replied to my inquiry:

Charlie,

Sorry for the tardy reply.

It will work just fine with the m30, as long your're getting some kind of OBC reading on mileage (probably like 55mpg?)

It has an internal software range that works for most cars, the fine-tuning is done via a potentiometer on the board.

I'm def getting one.

I installed this over the weekend, and it works great.



I installed it on the female side of C103, inline with the WT/BK wire that goes to the OBC. For power, I used a spare 12V from the main relay that was part of the B35 harness and was unused. For ground, I used the ground for the flashlight charger.

The potentiometer lets you adjust the signal to the OBC/econometer:

Keep the adjustment knob in the middle to start and get an idea of where your corrected mileage stands. Turning it to the left will increase your displayed mileage, turning it right will decrease displayed mileage.

I started with it all the way to the right and I showed 7-8mpg after a 4-5 mile drive. Then, with it all the way to the left, I showed 26pmg on the same loop. Putting it roughly in the middle it then showed 15mpg.

A few tankfuls of fuel and it will be easy to dial in. Great product; would buy again.

[Sharkland]

Hi !

Two pics of the nearly ended project...







Hope you'll like it

[c3p0]

I have a m30b35 in my 84 533i. I'm running a seta harness. My question is how do I get the check engine light to work. I'm pretty sure I don't have the bulb in the 84 cluster

[Bimmerguy2002]

You would need to run a small wire from the c103 to the bulb socket and then the second wire out of the back would go to a ground to complete the circuit. It should be buried under there if you take the cluster out and look around, ive seen one that i had to fish all the way down to find it toward the column.

[c3p0]

I looked around last night and I could not find it any where. Took the cluster out and looked around too

[c3p0]

Also. What color wire should I be looking for. I think it's grey. But not 1000%

[ronsea]

Im having trouble with mounts... i have a b35 out of a 91 e34 and a 88 528e. i purchased both left and right side mount adapters from Koala so that i could use my stock mounts and neither side fits. i noticed someone else in this thread had the same problem with the same company. are there any other companies that sell mounts for this swap or any stock mounts that i could use? e28 m5 mounts maybe? i dont know how to weld so making my own is not an option.

[Tarmo321]

Helllo!

What kind of instrument clusters could I use on my e28 with M30B35 swap? Does other M30s cluster work also? Or could I use E34 ones maybe or are they different?

[D Unit]

What custom exhaust specs do you guys suggest for the m30b35? I have an e23 and am still using the b34 exhaust manifolds as well. Should I got Y pipe --> 2.5" piping --> Magnoflow muffler?

[M M]

I just want to say a big thank you to all those who put information into this thread. I have just completed the B35 swap in my eta and having this thread made things very easy. Even the wiring matched up perfectly (aside from a couple colors) to my Euro spec wiring.

[c3p0]

ve been running my 1.3 swap for a while now using a ETA harness, i noticed that when i turn my AC on the AUX fan does not turn on, i know the low speed works, i tested it today, any input ?