Yamaha R6 trigger cam sync problem-no RPM

[MWfire]

I always make connectio between analog and power ground in vems.
yelow line

If it were that simple they'd have done that in the design.
The reason for the ground wire rules is because of the amount of current that the grounds have to deal with.  The resistance of the wires is tiny, but when the coils, injectors and solenoids are all firing away the grounds can be handling many 10s of amps.  Say for example the resistance of the grounds is 0.05Ohm and you've got a load of 10amps being grounded, then you can expect a voltage rise of V = 10 * 0.05 = 0.5v  Not much... but unless the sensor ground is not biased by the voltage increase it will be subjects to false readings - temperatures and pressure values are very discrete and having them change as your revs rise would not be a good thing.

if grounds are connect correct, then thru sensor ground current will be low(less then 0.05A). But if somethink isn't good, p259 will survive.

[[email protected]]

Current is not the issue, its the rise in voltage upsetting the zero point of the ADC.

[GintsK]

Hi!

Rob, where you see the difference between MWfires jumper inside unit and these two pictures?
http://www.vems.co.uk/VEMSUserManual/VEMSGrounds.png
http://www.vems.co.uk/VEMSUserManual/VEMSToFactoryGrounds.png

In both cases spikes living in power ground copies to analog ground. Is it good or is it bad?

Other way to to grounding is take analog ground from separate grounding point (but from same place/part as power grounds). Then analaog ground is free from spikes in power ground. But cons is voltage difference between analog ground and power ground inside ECU during high current trough power ground. May be it is bad for famous P259 where both grounds are connected inside chip. But this variant works on many of my cars w/o any problems. Many OE systems are grounded in this way - analog ground is free from current influences.

It is confusing part...

Gints

[lost]

I always make connectio between analog and power ground in vems.
yelow line

On vems v3.5, are these two points analog&power grounds?
Can i make small wire bridge like on your picture?

And what goes to small empty space below? additional vr chip?

Thx

[MWfire]

Yes, you can make bridge between these two poitns.
I use 0.5-1mm wire for that(1-1.5cm long)
Yes, space is for second vr senzor(for hall you don't need that chip).

[Bubba Zanetti]

Again problems with RPM 

But this is far, far more crazier then previous problem 



This is the story:

After I managed to solve RPM problems related to infamous P259, I also managed to start engine few times (though it was extremely hard to start due various other problems), play with idle mixture, and rev it couple of times to 6000 RPM.

Then I unplugged car battery, and VEMS ECU was left mounted in car chassis, more then one month, intact.

Then "USB-serial-adapter" agony started - I bought USB-serial adapter from VEMS shop trying to connect with my Acer laptop (1.7 GHz, 512 MB RAM) but even with fresh drivers and practically all settings changed, I never, ever connected to VEMS, nothing ever happened.




So I used my old Sony Vaio laptop instead (with RS232 port), made fresh Win XP installation , and installed Megatune package containing 1.1.47 firmware.



1. first, I couldn't install firmware - for some reason "firmware_upload.bat" script didn't worked,



2. then I somehow managed to upload firmware, but when starting Megatune and choosing correct 16x14 STD profile, I've got some strange errors, like " "



3. hm, then after trying starting Megatune numerous times, I've got Meagtune working, but with bizzare readings: RPM's and all sensor readings  went wild with engine turned off.



4. I then decided to remove this MT package, and install new version of Vemstune, with 1.1.61. firmware, that worked with my configuration - install went pretty much  straightforward, all sensor readings were normal, but when cranking there was again no RPM reading

I checked all primary, secondary and ignition settings at least four times, but everything seemed like before.

Then I tried to crank car, and while cranking, I DISCONNECT cam sync sensor and ONLY THEN I've got RPM reading, but no spark !!! 

Hm, then I tried to connect cam sync sensor while cranking but there was no spark, all four outputs were dead. 



5. OK, as I didn't made any changes to wiring harness, engine sensors, connectors  and/or ECU internal mods after I started engine last time, I was CONVINCED it has to be firmware/software related problem - so I installed these firmwares:

-1.0.23,
-1.0.78,
-1.1.47,
-1.1.59,
-1.1.61,
-and again 1.1.65 - nothing, no RPM reading with secondary trigger enabled.



6. then next logical step in ECU troubleshooting was to bang my head violently couple of times directly to Cr-Mo chassis - still no RPM readings , but at least I felt slightly better 



7. I tried to turn off  "Secondary trigger" - and then I've got RPM readings when cranking - so primary trigger works normally, and I guess that P259 chip is still alive & kicking (crossed fingers).



What to do next - I am really exhausted of ideas, and I need to start the car ASAP....is it possible that secondary trigger input died for some reason?

Is it possible that HF from TIG welding can destroy processor inputs, even with battery terminals disconnected?