I am working on a BMW 635 csi '79


I am going full sequential ignition and injection in the future but for now wasted spark is OK.

All hardware is ready now only camsync not. For now I want to run wasted spark using COPs. But the inject and ignition outputs are a mystery for me.

=> start to document what you know, eg.

A1 I asssume you are running the latest released firmware/megatune package ? If not, get it from [here] (unzip and run megatune) then if you take a look at settings -> ignition settings, you'll find the option "Dual output mode"; enable that. After that set up the ignition channels in settings -> Ignition outputs dual setting screen. - DB

Verification of setting

After setting it, you can verify by doing a Man mcd dump in TerminalProgram 9600,8n1 (exit MegaTune while doing this) that ign_out=72 (not 70, that is normal dummy-ignition).

The mcd and mct are the standard canonical dump of firmware variables. The information as suggested on IssueReports is the recommended way to document settings, it allows easy reproduction of setup, quick review by experts (which increases your chance to catch config errors if your setup intentions and wiring is also documented) and avoids any human error or MegaTune problem (using very old version that is incompatible with recent firmware, or MegaTune bug). You can use MegaTune screendump for spectacularity, but mcd, mct dump is also highly recommended.

global.h describes variables:
uint8_t ign_out;     // EDIS:0x0? dummy: 0x7? disable:0xff bit1: ign_dual_out bit0: invertout

EGT - the standard EGT sensor is used (from WebShop)

Q In the beginning I tested the egt when vems was not yet installed everything was fine and I had a nice reading. But when Vems is installed it doesn’t work anymore most of the time it says 0 en than for a msec 150 C and 300 C en than 0 again.


ignition settings => ign_dualout enabled

ignition outputs. TODO: document firing sequence!!!

Pair 1

Coil 1 to pin 35

Coil 6 to pin 33

Pair 2

Coil 2 to pin 11

Coil 5 to pin 12

Pair 3

Coil 3 to pin 34

Coil 4 to pin 36

Ignition output testing

when using the keyboard command mdnxx, I get a 2 nice sparks for all 3 pairs

I'm now testing the ignition coils and all work well with keyboard command mdnxx. But when I crank the engine nothing happens even the spark advance in megatune background stays red and says -1.7 degrees => this does NOT sound good for cranking advance (usually 5..10 degrees). Check knock_default_retard (set to 0) and idle_advance (set to 0 for now).

A2 I guess you dont see rpm while cranking either (or irratic rpm numbers) it seems you have your trigger tooth and another trigger tooth swapped in config. Since you have a 60-2 on a 6 cylinder, another trigger tooth should be 60 / 3 = 20 (14 hex) trigger tooth should be adjusted so that ign_tdc_delay is around 60 degrees. (6 is usually a good starting point) - DB

Q3 The rpm number is good now but stil no spark while cranking

A3 your ign_out is set to 0x02, that should be 0x72 (DUMMY ignition + ignition_dual_out) easily adjusted from megatune->ignition settings->ignition driver type: DUMMY. (verify config afterwards) - DB

[\ MembersPage/Bvd/Config]

Primary trigger

original 60-2 wheel (BMW e34 ’90) Is that VR ?????

Camsync: [Hall-Effect Vane sensor]

Camsync sensor position with the info on GenBoard/Manual/InputTriggerCamSync

I made the following drawing to figure out where the camsync must be placed


So if i turn the crankshaft to 150 degrees before TDC of cilinder 1 the Hall sensor mounted on the camshaft should give a reset puls.

Please correct me if I'm wrong


I want to connect the rpm gauge and followed the directions from this webstore page: [inductor]

I don't completely understand it so i made a drawing


This is the correct way to connect the inductor (inductive pullup). Make sure the output you use have power-IGBT-output (not logiclevel).

See DocsPage bottom for file area to upload images.

alternatively you can upload the pictures from your computer to another image hosting ("gallery") site like [ , than copy and paste the url for the image into you wiki page.