No ignition control

[supercharger_mark]

Hi
I'm building a drift car with my son and need some help.
Its a Nissan 180SX with an RB20DET 6cyl motor. 36-1 missing tooth crank wheel, VR sensor (NO CAM SENSOR).
Ignition module, 3 wire COP. Wasted spark. Hi impedance injectors.
Megasquart3 V3.57 assembled, firmware version MS3 release 1.2.4 20150123 GMT (c)JSM/KC.
TunerStudio version MS V2.6.14.
The motor starts and runs smooth with no load, no problem adjusting fuel, (still needs tuning).
My problem is, I cannot adjust the ignition timing, if I fix the advance to 10 deg the timing still advances and retards when revving, I tried setting the ignition table to all 10 deg with no affect, originally I had the primary ignition load set to speed density and changed it to alpha n, still with no affect.
At idle 750RPM the timing sits at 30 deg BTDC and advances up to appx 60 deg.
I've triple checked the wiring and the settings and I'm now stumped.
Can someone please help?

PS my msl file is too big to be accepted.

[Matt Cramer]

1.2.4 is a very old code - what about using the latest?

[supercharger_mark]

Sorry Matt That was a typo, its 1.3.4 code.
I'll send a smaller msl file tomorrow.
Cheers
Mark.

[slow_hemi6]

Looks like you are using the HT inductive clamp on a low voltage wire at the coil. I don't know if I would have any faith in the accuracy of that setup. You'd have to run a short HT lead from the cop unit to the spark plug and trigger with the clamp on that.

[jsmcortina]

I'd also question the strobe pickup. This has to be solved as timing must be checked.

As a test to see if timing is truly being controlled, set "Fixed Timing" and set it to 10, 15, 20 deg at idle. The engine note will change if the timing is being changed.

James

[supercharger_mark]

Thanks guys, you were both right, the timing is doing what it should, I wont make that mistake again, see photo.
My next issue (sorry to say) is the engine wont rev over 3000rpm without missing badly, it acts and sounds like a rev limiter but the settings I have are way above that, same thing under 800 rpm.
I've searched through the msq without any joy and although I don't understand a lot of the graphs in MegaLogViewer, no joy there either.
See attached files
Cheers
Mark.

[slow_hemi6]

You are loosing sync on the tach input. http://www.msextra.com/doc/pdf/html/Meg ... 4-134.html

[supercharger_mark]

Thanks for the link HEMI
I spent a few hrs re routing the wires but still no joy, I then removed the shrouded VR sensor wirers from the harness and ran them separately without any change.
I can see the problem is "loosing sink" I've read through the forum till I couldn't keep my eyes open, there is talk about putting a resister from the VR sensor, but I could not find a
wiring diagram and I'm not real good with electronic jargon, (it would have to be in layman's terms).
The VR sensor I'm using is out of a Honda CBR1000 bike, I have another out of a Subaru which I'll try, if that doesn't work I'll try a hall sensor.
any other suggestions would be appreciated.
Cheers
Mark.

[slow_hemi6]

You usually want to try and capture that sync loss on Tuner Studio's high speed composite logger or for more intermittent ones the sync loss logger can be good.

[prof315]

Use the TOOTH logger not the composite logger and check to see if you have the polarity inverted on your VR sensor. And based on your description of what is happening it sounds like that is the case. A quick way to test without using the tooth logger is to change the capture edge of the sensor. If you are currently using rising edge in the ignition options/wheel decoder settings switch to falling edge or vice versa.

[slow_hemi6]

Use the TOOTH logger not the composite logger

I would still like to see a composite, probably why I asked for one.

[supercharger_mark]

Hi again
I had a chance to do a few things with the car on the weekend.
I changed the VR sensor for a subaru one, and that changed the charactoristics.
If I set the gap to 1mm it looses sync badly and wont rev at all, if I increase the gap to 3-4mm it runs perfect at all rpms, but will not start unless I close the gap again. I tried changing the ign input capture from rising edge to falling edge but the engine would not run at all on that setting, I swaped the VR senser wires around but still no go.
I tried adjusting the VR conditioner, trim pot R11 threshold voltage and R32 hysteresis level, with no change, I solderd a 1k ohm resistor to the R57 area for a pull-up on the V3.57 board as suggested (DIY support, inside the V3.57 board) with no affect at all.
I've checked the Tach input jumpers for a VR sensor on jp1 (1-2) and j1 (3-4) on the board, they were correct.
It was also suggested in DIY support for VR sensers, to remove the pull up jumper on jp7 which I did but with no affect.
I think I read some where that putting a pull-up resister appx 7-10k ohms on the VR sensor did the trick??? I need to buy a resister to try that.
The attached files have the VR sensor gap set at 1.5mm which looses sync at idle and stumbles when the throttle is opened then runs ok at higher revs. (a compromise)
I'm old school (carbies points etc) so if you have any suggestions please dum it down for me, this stuff dose my head in.
Cheers
Mark.

2016-05-27_14.32.22.csv

2016-05-30_20.23.10.csv

2016-05-30_20.25.58.csv

[supercharger_mark]

A couple more attachments.

[supercharger_mark]

Hi Hemi
There should be a composite log in that lot.
Cheers
Mark.

[slow_hemi6]

In the logs you can definitely see it short count the missing tooth and loose sync. When the average 35th tooth is around 4mS (time taken for tooth plus missing tooth) it will sometimes see that 35th as 2.2mS. A standard tooth at that rpm takes about 1.9mS so it over counts by seeing the missing tooth as just a std tooth. The over count triggers a sync loss. I can't really be too much help with sorting the VR as I use hall sensors. The basics are making sure the wheel is true and does not have run out. Making sure the tooth edges are sharp and not rounded. Making sure the sensor is well mounted so vibration is not a factor. Getting the gap right and tuning the pots. IIRC, adding series or shunt resistors is for sensors that produce quite high voltage peaks as the revs increase.

[supercharger_mark]

OK, I have a lathe and I've already trued the wheel, the tooth edges are sharp, and although the sensor mount looks OK to me, maybe it could be more ridged so I will remount that just in case.
Q, If the engine runs fine with a bigger VR air gap, could that mean the signal is too strong with a smaller gap, so would a resistor reduce the signal?
Or should I just buy a Hall sensor and try that?
Cheers
Mark.

[old guy]

Close up the gap and try a resistor. Get the gap as close as you can without hitting. Make sure your mount is is pretty stout as harmonics will vibrate a weak mount and cause problems.
Also make sure that your gaps between teeth are wider than the metal pole piece on the face of the vr sensor.