I have switched from a megasquirt to a Vems but have now problems with the trigger signals.
Primary and camsync trigger is hall.
Vems cannot properly detect trigger sequense from Nissan 300ZX hall module with 12-1 triggerwheel.
Car is race V8 engine, high compression and cranking at approx 80..113 rpm. The cranking rpm varies very much due to the high
compression.
When turning distributor by hand with ocsilloscope connected there is no doubt where missing tooth is. Allways 11 tooths between the
missing tooths and the camsync signal comes on triggertooth 0 (first tooth after missing tooth)
I have also tried disabling camsync all together, but it makes no difference.
When turning the distributor by hand (approx 80..100 rpm in vemstune) sometimes the sparkplugs ignite.
The rpm signal in vemstune (1.5.24) seems to be very stable. No flickering rpm signal.
Triggerlog when engine is cranking. (with wrong ignition output settings, but trigger setup is correct)
http://www.vems.hu/files/perboddum/cranking.triggerlog
Triggerlog when distributor is driven by hand
http://www.vems.hu/files/perboddum/turnbyhand1.triggerlog
http://www.vems.hu/files/perboddum/turnbyhand2.triggerlog
Vems config
http://www.vems.hu/files/perboddum/setup6.vemscfg
Picture of triggerwheel 12-1
I really need some help to get this Vems setup to work.
Per i have reviewed your triggerlogs and indeed the periods between teeth seem very irregular.
1) Lets start out with with following, could you make a triggerlog of engine cranking 8-10 seconds without injector and ignition fuse to verify if the irregular periods are caused by some noise issue.
2) Secondly could you make another triggerlog (again 8-10 seconds) but then spinning the trigger not by hand but by some something with stable rpm (perhaps use a battery powered drill), that way we can verify, if with stable RPM the trigger periods are even.
If you upload both these triggerlogs to your memberspage i will review and provide hints on how to proceed.
Best regards, Dave
Thanks Dave
Scope of triggerwheel 12-1 with power drill at approx 200 rpm
I have done some more test with power drill (50...120 rpm) and the distributor connected to Vems.
Vemstune displays the rpm but as soon as rpm drops and then gains rpm again I often get PRI.trig error in Vemstune and the sparkplug stops sparking.
It seems to me that it is a combination of low rpm AND varying rpm at the same time that confuses Vems.
I can have steady 60 rpm and there are no trigger errors and the sparkplug ignites
Tomorrow morning I will try install the distributor and make the logs
Hello Per,
When reviewing your scope shots it seems there also is a very slow rise rate on the primary trigger pulses (red signal, ch1) could you set both probes to the same amplification, set the scope Y range the same for both channels, trigger on yellow signal (ch2) rising edge and make a much smaller timebase shot so i can accurately see:
1) falling secondary triggger (yellow, ch2) in center of screen and one or two primary edges (red, ch1) left and right.
2) additonally please supply the VEMS triggerlogs (.triggerlog files) as requested in previous query.
3) make sure the secondary trigger is enabled and connected to the VEMS when making these.
Best regards, Dave
Distributor connected to Vems and drill operated.
http://www.vems.hu/files/perboddum/drill1.triggerlog
http://www.vems.hu/files/perboddum/drill2.triggerlog
I cannot make a triggerlog or normal log, because Vems constantly looses the serial connection (physical serial COM1, not USB adapter) during cranking. Vems supply voltage is around 9.35 volt during cranking.
Note:Battery is in the back of the car.
Hello Per,
If the VEMS looses serial connection during cranking this means the ecu resets (most likely because of voltage dip during initial cranking engage) but if the ecu does not reconnect during cranking there might be some problem with the integrity of your GND wires from battery to chassis, GND from chassis to engine or VBATT cable from battery in the back to the engine. While performing the other checks it makes sense to verify these also (for good connection, corrosions, sufficient size etc.)
Best regards, Dave
Thanks Dave.
The car is rebuild from scratch with new wires in 2009. No rust or corrosion what so ever. Have only run some 4000km.
Connected 2 batteries and the engine fires up, but still looses sync at 1500 rpm. No camsync.
http://www.vems.hu/files/perboddum/running1.triggerlog
http://www.vems.hu/files/perboddum/running1.vemslog
With camsync.
http://www.vems.hu/files/perboddum/running2.triggerlog
http://www.vems.hu/files/perboddum/running2.vemslog
Hi Per,
Nice to see it running, but in your triggerlog with CAM sync i do not see secondary trigger showing up (perhaps you did not power cycle the ecu after making the changes in configuration ?). Before attempting anything else we should verify that all triggers are in working order _without fuse to INJ and IGN_ at cranking.
Very important in your running1/2.vemslogs, CLT/MAP IGN adjust table is not filled reasonably, please correct before attempting any further tests
Best regards, Dave
Hi Dave
Camsync is connected to EC36-13.
With scope connected to pin13 on Vems printboard I get a fine camsync signal. Why is it missing in the log.
I am pretty sure the previous triggerlog with camsync is recorded after a reboot.
This triggerlog is for sure after reboot.
http://www.vems.hu/files/perboddum/running3.triggerlog
Hello Per,
I have consolidated my request to single block perhaps this clears its up.
When reviewing your scope shots it seems there also is a very slow rise rate on the primary trigger pulses (red signal, ch1) could you set both probes to the same amplification, set the scope Y range the same for both channels, trigger on yellow signal (ch2) rising edge and make a much smaller timebase shot so i can accurately see:
1) falling secondary triggger (yellow, ch2) in center of screen and one or two primary edges (red, ch1) left and right.
2) Lets start out with with following, could you make a triggerlog of engine cranking 8-10 seconds without injector and ignition fuse to verify if the irregular periods are caused by some noise issue.
3) make sure the secondary trigger is enabled and connected to the VEMS when making these.
To summarize, before we have verified correct operation of BOTH triggers, no starting attempts (with fuel and spark) are required (even cordless drill tests are suitable for these scope tests, perhaps easier to perform than cranking the engine all the time).
Best regards, Dave
Hi Dave
Cranking engine triggerlog
http://www.vems.hu/files/perboddum/cranking2.triggerlog
My Vems config
http://www.vems.hu/files/perboddum/setup12.vemscfg
Scope with distributor (connected with 12volt and 1K pullup on trigger+camsync) drill operated.
Hi Per,
The scopeshots look perfect, i still suspect scope amplification difference (1X/10X) resulting in the X 5v/50v range to get same height on screen but lets not worry about that now.
I tried to review cranking2.triggerlog but the file seems to be empty. Could you re-upload or verify ? Thanks.
Best regards, Dave
Hi Dave
You are right. One probe set to x10 and the other x100.
Cranking triggerlog uploaded again
Have updated vemstune ini files from web. Was missing CLT/MAP ign settings. This solved loosing sync at 1500 rpm.
But it seems I still don't get camsync into triggerlog and vemstune signals Less sec.trig.
Trigger with camsync falling.
http://www.vems.hu/files/perboddum/cranking3.triggerlog
Trigger with camsync rising
http://www.vems.hu/files/perboddum/cranking4.triggerlog
scope of both signals during cranking. Watch the camsync.
Why does it behave like that when connected to vems. Both signals comes from the distributor Nissan hall unit.
Hi Per,
Great to hear updating ini file manual update provided you with the correct ini files to match your firmware (as recommended on GenBoard/UnderDevelopment/FirmwareChanges).
I have no idea whats going on with your secondary trigger signal, it seems some kind of noise superimposed on signal. Secondary trigger also does not show up in the triggerlog(s). My suggestion would be to disable secondary trigger for now, you are running distributer ignition anyway.
Make sure to check if your tdc calibration is set up correctly (with timing light) before attempting any further tuning.
Best regards, Dave
MembersPage/PerVolvo - Volvo 960 VEMS