Dirty rpm reading after upgrade 1.1.74 -> 1.1.80/81

[GintsK]

Hello, guys!
Yesterday I got strange problem. Hopeful config related. But can't find exact reason:
I run old M5 inline-6 with big turbo on dyno using 1.1.74.  60-2 w/o camsync. VR. Audi active coils using dual ign outputs.
  After spark plug reading I dedicate to migrate to 1.1.81 cause of fuel trimming possibility. And imediantly get dirty rpm signal. Same after downgrade to 1.1.80. But no trigger errors!
I made trigger log - it was full with unequal teeth timings. 0.77-1.22-0.87- and so on. Nothing even close to 1.00-1.00-1.00.
Log result (sorry - didn't save it) determines many missing gaps. Approx two per 10 teeths!
I tried to switch on filtering. as result - no rpm signal at all...
Back to 1.1.74 -> usual clean rpm signal...

Can someone try to find error in this config, please? (right click -> save as)
http://www.vems.hu/files/GintsK/v3.3_n002226-2010.10.09-15.04.01STRT.vemscfg

[Erikk]

I think you should use 6 Ignition outputs and your Reference tooth table should look like:

0
40
20
0
40
20

.


And your ignition output should look like:

0+1
4+5
2+3
0+1
4+5
2+3.

 

[mattias]

Erik is right, ever since 1.1.x came out it has been important to fully declare the whole 4-stroke cycle, even if you don't have cam sync.

I'm not sure why this would change between 1.1.74 and 1.1.81, but still it should be done.

In case you didn't, make the triggerlog at low rpm. 60-2 doesn't work at 1000 rpm, it will miss events in the log.

[GintsK]

Yes this could be the reason! Usually I fill all cycle. But in this case ECU previous runs on 1.1.53 with just three rows, then directly imported to 1.1.74....

Rpms at trigger log was >1000, right!

So it means issue should be easily reproducible on bench test. I will try to be proof!

Just checked my another similar problemless L6 1.1.81 config - it has 6 rows filled.

Thanks!

[Kartis]

What if u cant fill the whole cycle? Thinking of my mb v12?

[mattias]

12 cylinder, treat it as a 6 cyl engine.

[GintsK]

V12 usually consists from two separated L6. Key part is separate intakes. I use two VEMS units for V12 and V10 projects.
Then I can be sure both parts will always get right fueling. Independently from throttle synchronization.

But yes, of course it can be simplified.

[mattias]

The ignition out table and the ref tooth table will soon be expanded in firmware to allow 12 cylinder configurations without compromises.

Bear in mind that for a sequential ignition setup you need all 8 IGBT and the 4 stepper outputs. It's usually easier to implement as wasted spark (6 outputs), or using dual distributors (2 outputs).

GintsK: dual ECUs must be pretty cool to tune, like you say some are treated as two L6 engines. Like the BMW which has separate plenums for each cylinder bank, the easy way out for someone who installs an  aftermarket ECU is to connect the two plenums or modify to get a single throttle.

[GintsK]

Most of them are separate intakes. BMW, MB, Jaguar.... I have even 39liter V12 powerplant on woodgas - same.
Joining of two plenums from my point of view is more difficult than tuning of two ECUs. There are lack of free space usually. Throttles aren't close to each other.
And one more point. No one can't be sure about cam timing differences due to chain wear. So I prefer two EGO correction loops.