It's baffling. I'll do some more troubleshooting tonight.
I'll scope the signal with the engine controlled by the stock ECU and want to see if we have the same issue. Then will swap sensors.
I can also try and run it off my backup MS and see what that does.
Re: 2003 VVT test mule Miata
Posted: Sun Nov 20, 2016 3:21 pm
by kb1gtt
Perhaps the over-current condition broke something. Perhaps try a larger resistor, like 100kohm.
Re: 2003 VVT test mule Miata
Posted: Sun Nov 20, 2016 9:06 pm
by stefanst
Looks like the observed signal inversion is what is supposed to happen!
The pullup in the stock ECU is apparently to 12V. Trace below shows a signal floor of ~1.4V and top at 12V.
CAM Signal inverted.png (78.02 KiB) Viewed 33378 times
But it can't be all a current thing, since 3.3kOhm @12V and 1kOhm at 5V, which we used to have, should yield fairly comparable currents.
EDIT: I could install a resistor in the signal line and scope the current that way. 10Ohm at an estimated 5mA would give me 50mV. Enough to see, but unlikely to kill the signal.
Re: 2003 VVT test mule Miata
Posted: Sun Nov 20, 2016 10:22 pm
by stefanst
Measured current. At 10 Ohm we get a voltage drop of 75mV. So we get 7.5mA. Suggesting a total resistance of 1600 Ohm. The voltage drop on the sensor is approx 1.4V suggesting approx 190 Ohm for the sensor itself.
At 5V we want a total of ~670 Ohm to get 7.5mA. That leaves us with 470 Ohm for the pullup.
CAM current sniffer.png (66.15 KiB) Viewed 33376 times
Re: 2003 VVT test mule Miata
Posted: Sun Nov 20, 2016 10:36 pm
by kb1gtt
Beware that the MAX chip will clamp to 5V. So your impedance might get a bit wonky as you exceed 5V with your 12V pullup. The MAX chip has rail clamping diodes, which will dump to the 5V rail. When it dumps like this you will need something to consume this energy or your 5V will raise above 5V and potentially damage 5V devices.
Re: 2003 VVT test mule Miata
Posted: Mon Nov 21, 2016 2:02 am
by stefanst
Strange news everyone!
Looks like the behavior we observed is intentional. These are scope traces of the CAM sensor running with the stock ECU.
CAM signal while cranking around 200rpm (disconnected spark)
Stock ecu cam cranking.png (73.85 KiB) Viewed 33363 times
CAM signal with spark plugs, cranking and firing up within just one turn of the crank
Stock ecu cam starting.png (80.57 KiB) Viewed 33363 times
And with the engine running in idle
CAM Signal inverted.png (78.02 KiB) Viewed 33363 times
At low rpms the sensor signal goes from a normal low to high when it sees a trigger. At running rpms the signal inverts and goes from high to low. So our electronics are fine. They are reporting the signal as it is presented by the sensors and that is intentional. I haven't verified it yet, because the crank sensor wiring is such a pain to get to, but from what I've seen before it behaves the same way.
Over to software?
Re: 2003 VVT test mule Miata
Posted: Mon Nov 21, 2016 2:30 am
by kb1gtt
Pleasure talking with you @stefanst. Per our talking and testing, it appears that the OEM ECU exhibits this inverting signal that you captured above on the Frankenso board. I suspect this is caused by the hall sensor itself. I suspect that at low RPM, the hall sensor adjusts itself increasing an internal gain of an amplifier, such that it can capture the pulses which are generated by the lower magnetic fields that happen at the lower RPM's. Then once the pulses are coming in less than some certain amount of time, then it decreases the gain, and the pulses could potentially change at that point.
I wonder if there's a way this could be setup on a kind of jig which allows controlling of the RPM as well as measuring the RPM, then we could characterize the pulses based on RPM and see specifically when it happens and when it happens. I also wonder if we could tear one apart and find what the hall sensor is. Often these use an off the shelf hall sensor which may have a datasheet.
Re: 2003 VVT test mule Miata
Posted: Mon Nov 21, 2016 2:48 am
by stefanst
BTW: The cranking rpm looks to be 200rpm on the cam- that is 400rpm crank.
Re: 2003 VVT test mule Miata
Posted: Mon Nov 21, 2016 2:55 am
by AndreyB
On the one hand, since VVT sync is running on rising fronts only, software would work with this as is - nothing to change in the software. Below 200 rpm VVT would be a bit off but who cares below 200rpm.
Is that with 5K pull-up resistors?
On the other hand, does not this all sound a bit too complex to be true? WHY would they intentionally do that? Could it be that this crazy stuff is only happening to us because +5 pull-up?
Re: 2003 VVT test mule Miata
Posted: Mon Nov 21, 2016 2:58 am
by stefanst
Those signals are straight off the stock ECU (sensor output BEFORE the ECU).
So this has nothing to do with frankenso electronics at all...
Re: 2003 VVT test mule Miata
Posted: Mon Nov 21, 2016 3:14 am
by stefanst
I'll try, but since your '03 and my '03 have the same issue- and both on the cam and crank sensors, I am pretty certain that this is OK.
I think the trigger code is getting confused somehow. Using the crank as primary instead of cam may contribute.
On the '99 we trigger off cam as primary- correct? And the VVT uses crank as primary.
Let's look at the engine logger from before:
We get the 1-2-1-2 on the rising flanks on the cam. But we're missing spark and fuel events and then we even have something that looks like a double-event.
Can we run the '03 with the NB1 code, or is the phase shift between cam and crank wrong for it?
Re: 2003 VVT test mule Miata
Posted: Mon Nov 21, 2016 3:19 am
by AndreyB
stefanst wrote:Can we run the '03 with the NB1 code, or is the phase shift between cam and crank wrong for it?
I would expect that 03 with NB1 should be good enough for 1st run, there is a chance that global trigger offset would be needed - but maybe not.
I believe on NB1 the single CAM tooth is within the first 180 degrees of the 720 degrees engine cycle.
Re: 2003 VVT test mule Miata
Posted: Mon Nov 21, 2016 3:28 am
by stefanst
Do I remember right that we now use 0deg trigger angle offset for NB1 or is it still 276?
I can probably try tomorrow evening, but then I'm off for T-day week with the family in SC. I really hope to get it started first though
That's assuming i have not messed up anything moving it from offset to tdcPosition.
Re: 2003 VVT test mule Miata
Posted: Mon Nov 21, 2016 11:50 pm
by stefanst
Looks like the NB1 trigger evaluation is not happy with running the NB2 engine.
EDIT: Because I know the question is coming. Yes I tried both: Use Rise Edge Only yes and no.
2016-11-21_18_46rpm_0_maf_NaN.png (35.72 KiB) Viewed 33352 times
We can read the signal, but there is no injectioning or ignitioning going on.
Message log:
There is a small chance it would work if you change onlyFront=Yes to onlyFront=No in TS
Re: 2003 VVT test mule Miata
Posted: Tue Nov 22, 2016 1:36 am
by stefanst
Tried all four permutations of
use only rising edge true/false
and
VVT use rise front true/false
Not a single blip of rpm recognition.
Re: 2003 VVT test mule Miata
Posted: Tue Nov 22, 2016 1:37 am
by AndreyB
I am done fixing the exhaust, now I need to put it back on the car and I can lower it.
Re: 2003 VVT test mule Miata
Posted: Thu Nov 24, 2016 3:43 am
by AndreyB
enable trigger_details helps understand these kinds of issues. here with VVT we have two synchronizations - crank signal - which for us is trigger synchronization - is one, and VVT pattern synchronization is the other. Both values had issues on my car, trigger shape is hard-coded into the firmware, VVT ratio is configurable via TS.
2016-11-23 22_15: EngineState: gap=1.23/0.80/1.21 @ 1 while expected 0.75/0.98 and 0.00/100000.00 error=0
2016-11-23 22_15: EngineState: gap=0.81/1.23/0.80 @ 3 while expected 0.75/0.98 and 0.00/100000.00 error=0
2016-11-23 22_15: EngineState: vvt ratio 0.90
2016-11-23 22_15: EngineState: vvt ratio 0.09
2016-11-23 22_15: EngineState: gap=1.22/0.81/1.23 @ 1 while expected 0.75/0.98 and 0.00/100000.00 error=0
2016-11-23 22_15: EngineState: gap=0.81/1.22/0.81 @ 3 while expected 0.75/0.98 and 0.00/100000.00 error=0
2016-11-23 22_15: EngineState: gap=1.23/0.81/1.22 @ 1 while expected 0.75/0.98 and 0.00/100000.00 error=0
2016-11-23 22_15: EngineState: gap=0.81/1.23/0.81 @ 3 while expected 0.75/0.98 and 0.00/100000.00 error=0
2016-11-23 22_15: EngineState: vvt ratio 11.26
2016-11-23 22_15: EngineState: looks good: vvt ratio 11.26
2016-11-23 22_15: EngineState: gap=1.22/0.81/1.23 @ 1 while expected 0.75/0.98 and 0.00/100000.00 error=0
2016-11-23 22_15: EngineState: gap=0.80/1.22/0.81 @ 3 while expected 0.75/0.98 and 0.00/100000.00 error=0
2016-11-23 22_15: EngineState: gap=1.23/0.80/1.22 @ 1 while expected 0.75/0.98 and 0.00/100000.00 error=0
2016-11-23 22_15: EngineState: gap=0.81/1.23/0.80 @ 3 while expected 0.75/0.98 and 0.00/100000.00 error=0
2016-11-23 22_15: EngineState: vvt ratio 0.90
2016-11-23 22_15: EngineState: vvt ratio 0.09
1.22/0.81/1.23 means we have 1.23 ratio between current and previous gap followed by 0.81 followed by 1.22
Now with the fix the firmware expects the gap between 0.75 and 0.98 to sync trigger (NB1 value is about 1.5 and it did not work)
VVT messages are separate - we have a cycle of 0.9 followed by 0.09 followed by 11.26
New defaults are from 8 to 14 range, within that range you get "looks good: vvt ratio 11.26" message
Re: 2003 VVT test mule Miata
Posted: Thu Nov 24, 2016 3:46 am
by AndreyB
With these values I am getting some puffs, but no running
Re: 2003 VVT test mule Miata
Posted: Thu Nov 24, 2016 2:41 pm
by stefanst
Could ignition timing be off now? I seem to remember that for start we should get ignition just a few degrees before the crank triggers on the wider part of the pattern. This is going from memory though....
Re: 2003 VVT test mule Miata #27
Posted: Fri Nov 25, 2016 2:26 am
by AndreyB
firmware 20161124 (synchronization gap widened to 0.35-0.98
Pre-warmed on stock ECU
still no MAP no AFR
global trigger offset 670 (once we measure the exact angle this would be moved into trigger defaults)
It runs
UPDATE: looks 5K pull-up resistors are the way to get proper trigger input with MAX9926 on Frankenso
Re: 2003 VVT test mule Miata #27
Posted: Fri Nov 25, 2016 4:50 pm
by stefanst
Congratulations. Another runner!
So, bets are lost, blame will be shifted, heads will roll. But most importantly burritos will need eating. No turkey burritos though. I had enough turkey for a while...
Do you already have the wideband installed? Curious to see if your stock ECU is running as rich in full throttle as mine...
Re: 2003 VVT test mule Miata #27
Posted: Sun Nov 27, 2016 7:58 pm
by stefanst
That last version did the trick!
The engine fired right up. And then stalled, because there's no tune yet, but it starts up without any trouble. It actually starts faster than my '99 with MS
These are the settings I used, stolen from @s tune.
VVT trigger working.png (32.96 KiB) Viewed 33277 times
Now to hook up the rest of the sensors and tune this engine!
Re: 2003 VVT test mule Miata #27
Posted: Sun Nov 27, 2016 9:31 pm
by kb1gtt
Sweet, and good to hear. I can't wait to see it tuned.
Re: red 2003 VVT test mule Miata #27
Posted: Mon Nov 28, 2016 3:18 am
by stefanst
So- had the car kind of idling, but realized that while the MAP sensor was connected, it was not connected to the intake. As a result the car was running insanely rich. I'm also experiencing trouble with the alternator control. I wired it already (HL5/PE10), but disabled it in the firmware. However, it looks like the alternator REALLY wants to charge my battery. Voltage spiking to 18V.
Do the HL outputs default to high or low?
Re: red 2003 VVT test mule Miata #27
Posted: Mon Nov 28, 2016 11:20 am
by kb1gtt
I know the STM has configurable weak internal pull up and pull down resistors. I'll have to rely on @russian to comment about how those are configured in software. I do not know if the default output would be 100% alternator or 0% alternator. Sounds like it's currently full alternator. If the STM output is floating it's not guaranteed to be either hi or low.
I know that in ChibiOS 3.0 in board.h they have #defines for PIN_PUPDR_PULLUP, PIN_PUPDR_PULLDOWN and PIN_PUPDR_FLOATING. I believe the defaults are that everything is floating, then changed via software as things are initialized. I also know that these can be set such that they are in that default state when powered on and you do not have to wait software to initialize.
Re: red 2003 VVT test mule Miata #27
Posted: Mon Nov 28, 2016 3:16 pm
by AndreyB
stefanst wrote:I wired it already (HL5/PE10), but disabled it in the firmware.
I seem to recall the internal pull up and pull down are kind of weak, something like 10k or 50k. The external pull down on the not yet released R0.5 was to allow for a guaranteed pull down independent of the software.
So default should be pulled down, which I seem to recall should prevent current from flowing in the green wire, and therefor not excite the field windings, and no alternator. Is there a schematic for the alternator / charging circuit? I'm not sure if low side drive would be 100% or 0% alternator. I think the field is connected to your battery negative, but perhaps your circuit has the battery connected to the battery positive.
Re: red 2003 VVT test mule Miata #27
Posted: Mon Dec 12, 2016 2:55 pm
by AndreyB
Important and boring milestone for the new test mule