Ignition on a Mini-Turbo (No injectors)

Maximum planned boost is 0,8bar = 11,76PSI = 80Kpa, so max MAP reading will be 180KPa.

Planned rev limit is 7500 RPM

Project state



Sensors - already mounted:



The primary trigger input channel must be set up with the relevant jumper to VR-type input (so LM1815 is used).

I have uploaded new and better pictures of the board, they can be seen here: MartinFranck\Pictures


Wasted spark: 2 channels for 4 cylinders.

ign_dwelll4=27 # hex(27)=dec (39) ; 39 * 64 us = 2500 us dwell

is a good starting value, but depending on your coil, you might need to go higher to fire powerful enough spark at boost.

See "Measure current consumption" section on DummyIgnition.

Ignition Problem

In the high RPM area (above ... RPM) and only during driving (not in neutral) when pushing the throttle (above MAP > ... kPa ), the spark seems too weak.

Study DummyIgnition a bit. Igniting rich mixtures at high-boost is often demanding.

Document your setup (please split your ignition related documentation to a subpage) so people get a chance to help you:

The VR sensor seems to be good if the RPM signal is OK, and wheel-error does not increase after engine is started.

Pin connections and h[2] table

Pin connections can be seen here .....

Some very important settings like

h[2]=05 00 05 00 05 00 05 00


Ignition advance table

described in the n[ ] table (8x8 or 16x8)

Obviously, lower ignition advance is needed at highy MAP (> 100 kPa is possible because of the turbo). This means n[7] will hold lower values than n[0]

The following kpa and rpm ranges could be used (or other can be good too):

r[0] = 07 ... <5 RPM values of your choice> ... 40 48 (Also which format is the numbers)

k[0] = 18 40 64 90 B0 ... <2 values of your choice> .. FF (18 40 64 what is these numbers in e.g Hex ?)

You can take a look at my table file, it has plenty of hints should be enough to get you going: - DB


Q: Have I understood it correctly, that if I want the ignition advance too be 30 deg, that i then should multiplicat with 2, so that I should write 60 deg = 3C (Is this correct)

A: That is incorrect, the timing unit of the ignition map (n) and ign_crank_advance is 0.25 degree. Therefore, 30 degrees = 30 x 4 = 120 = 0x78.

Q: When I try too comunicate with the V3-controller true megatune I get the folowing message

Controller voltage too low for reliable FLAS-BurnĂ?­ng

But I have tried too use a separate power supply (220v-12v), but it do not help, what can be wrong.

The MegaTune Flash-burning warning itself is harmless, it is for inferior ECMs (not sure if it can be disabled in vems.ini somehow). v3.x can write the flash (actually, config is stored in EEPROM) from 6V board-supply-voltage and up. However, if the VBatt is shown bad in MegaTune (or LCD page 6 mlp06), the dwell calculation and even the injector pulsewidth and stepper iac in some cases will be effected. So adjust batt_cal (default 0xBC or so since v3.2; batt_cal=0xFF results in highest reading value, significantly higher than actual voltage) to get VBatt reading within +-0.4V of actual value (take care, battfac is sg. completely different).

A: Some people have had problems with operating a v3 controller with computer power supplies which are ~1A but only when running WBO2 where the heater eats more current especially when still cold. You may need to try with an actual automotive battery.

Tachometer problems

Q: Tachometer problems, my tachometer does not show the correct RPM because I am using wasted spark, can I connect the Tachometer to the V3-controller an get the correct RPM, ore are the other obsentions ?

A: How is it attached right now? You should use an unused ign channel pin on EC36. I see you use two wasted spark coils, attached to EC36-34 and EC36-36, and that its a four cylinder. Attach the tach wire to an ignition output, and your add the value for that channel to every fourth h[2] array element.

The Tacho is connected to the wiring from Pin 12.

My h[2] table is curently like this: h[2]=05 00 05 00 05 00 05 00

The wasted spark coil is connected too pin 12 (cyl 2-3) and 35 (cyl 1-4)

If I have understood you correctly the h[2] should look like this if I use ign channel 01

h[2]= 05 00 01 05 00 01 05 00 very interesting trick, it might work if another_trigger_tooth=09 instead of 0x12 (decimal 18). However, it might restrict dwell length at high-RPM ? There is a patch coming from MembersPage/Gabor, that might be cleaner (and work even for a v8 COP setup)