MembersPage/SkassaSubaruNewtrigger (2010-05-31 21:47:41)

This page contains all test of the new Subaru Trigger code



Trying to find the Subaru trigger problem while cranking, i have done some measurements.

My cheap, only 2k$ Agilent DSO3062A oscilloscope, does only have a sample rate of 1 to 5 kSa/s when measuring

over these relatively long times.. :o(

The pulses at LM1815 output is default 25 micro sec. To relyable capture any pulses at LM1815.12 i have therefore

made an pulse extender. The following measurements is done with this extender between probe at CH2 and LM 1815.12.


NewFile_00:

Measurements at secondary trigger.

CH1 at LM1815 pin3

CH2 at LM1815 pin12 (extender between)

Cranking at approx. 150 rpm

rpm signal in VemsTune jumps time to time to 170 rpm

Fuelpump off


NewFile_01:

Measurements at secondary trigger.

CH1 at LM1815 pin3

CH2 at LM1815 pin12 (extender between)

Cranking at approx. 150 rpm

rpm signal in VemsTune jumps a lot

Fuelpump on

mis/backfiring!!


NewFile_02:

Measurements at secondary trigger.

CH1 at LM1815 pin3

CH2 at LM1815 pin12 (extender between)

Cranking at approx. 120 rpm

rpm signal in VemsTune jumps to 170 rpm, at the exact time the noise pulse is seen at the scope.

Fuelpump off


NewFile_03 to NewFile_05: (Different zoom's at the same shot)

Measurements at secondary trigger.

CH1 at LM1815 pin3

CH2 at LM1815 pin12 (extender between)

Cranking at approx. 150 rpm

rpm signal in VemsTune jumps time to time to 3000 rpm

Fuelpump on

pin5 is now tied to Vcc. This has resulted in no noise at pin12, but still misfiring..


NewFile_0A

Waveform 1.

Measurements at secondary trigger.

CH1 at LM1815 pin3

CH2 at LM1815 pin12 (extender between)

Cranking at approx. 150 rpm

rpm signal in VemsTune jumps time to time to 3000 rpm

Fuelpump on

pin5 tied to Vcc

10nF at C31, C34, C30, C33

Log 21.24.17


NewFile_0B

Waveform 2.

Measurements at secondary trigger.

CH1 at LM1815 pin3

CH2 at LM1815 pin12 (extender between)

Cranking at approx. 150 rpm

rpm signal in VemsTune jumps time to time to 3000 rpm

Fuelpump on

pin5 tied to Vcc

10nF at C31, C34, C30, C33

10k pulldown at both trigger inputs

Log 21.55.45


Log 22.01.02 Ignition lock 15_degrees


NewFile_0C & _0D

Waveform 3.

Measurements at secondary trigger.

CH1 at LM1815 pin3

CH2 at LM1815 pin12 (extender between)

Cranking at approx. 150 rpm

rpm signal in VemsTune jumps time to time to 3000 rpm

Fuelpump on

pin5 tied to Vcc

10nF at C31, C34, C30, C33

10k pulldown at both trigger inputs


NewFile_0E & _0F

Waveform 4.

Measurements at secondary trigger.

CH1 at LM1815 pin3

CH2 at LM1815 pin12 (extender between)

Cranking at approx. 150 rpm

rpm signal in VemsTune jumps time to time to 3000 rpm

Fuelpump on

pin5 tied to Vcc

10nF at C31, C34, C30, C33

10k pulldown at both trigger inputs

Ignition lock 15_degrees


NewFile_10 & 20 (_10 waveform at USB)

To verify that there is correct signal from both LM1815.12.

Measurements at primary and secondary trigger.

CH1 at LM1815 pin12, primary

CH2 at LM1815 pin12, secondary

Fuelpump off


NewFile_30, 40, 50 & 60 (Same scope shot, different zoom's etc.)

Waveform 5.

Measurements at primary and secondary trigger.

CH1 at LM1815 pin12, primary

CH2 at LM1815 pin12, secondary

Fuelpump on

Misfiring


After varming up the engine with old ECU, it's possible to start the engine

with VEMS ECU.

At this time the engine cranks at approx. 200 rpm. A short misfire at startup,

but the engine overcome this and starts anyway.

When the engine revs up, misfire apears above approx. 2500 rpm.


Trying to avoid this problem, i removed both pin5's from Vcc.

Logfile 18:00:10

Trigger log 18:00:52

Didn't chance anything


2 x 10k pulldown is then removed.

Didn't chance anything


2 x 10nF at input's is then removed

Now the engine can't start at all. Misfires and rpm in Vemstune jums to > 50.000 rpm!!


2 x 10nF is mounted again, and we are back to a working system when the engine is hot,

and the rpm is kept under 2500 rpm.....

Ole Blach 2010-05-30


28/5-2010

Did some more test today.

Status car is not running.

All test results will be published Saturday

Scooped signals to the processor and did not find any thing wrong.

Stable rpm until it starts to fire then rpm spikes to 3000 rpm. Symptoms like the old trigger setup.

When the engine starts to run fast it looses sync.


What we have seen 2010-05-24

We have stable 160 rpm at cranking fuel pump off.

When we cranking the car it´s stable in beginning it fires up to 300-600 rpm then random fires and rpm is no longer stable.

Its like it runs only on two cylinders (firing correct) but then losing sync.

We see some correct firing´s but also ignition fires at different times than it should. Obviously there is noise in the signal, that must be filtered.

Question: Haw is this code tested and what signal is used?

We have big trouble scoping the output of LM1815 because of the short signal like 15 micro sec. It should be a bit higher (20-30 usec), but you can enlarge it very easily, see below.

I would suggests that we use the p259 led´s output. When the processor get signal from lm1815 Pre/sec trigger we set the output high for 0.5 sec. This will give us a chance to see and measure what goes in and out of lm1815.

Triggerlog also shows the time of the pulse (although currently for the primary trigger only).

Watching the input with analog scope is of primary importance. Even if the output is perfect, if the input is on the edge, it can break any time (eg. in cold).


Analog scopeshots ? do you have some ?

http://www.syvecs.com/forum/viewtopic.php?f=6&t=110&p=474&hilit=trigger+pattern+advisory+note#p474

If the input is biased properly, the LM1815 adaptive filtering should filter out small amplitude "phantom-tooth" pulses in the subaru. I didn't see your scope so only you can judge the offending amplitude. 10-30% should not trigg, and with lower R181 / R182 even higher amplitude offenders can be filtered out

Maybe the noise is capacitively injected by ignition ? It could save a LOT of time (even 1 week) to route the VR signals via properly shielded cable (with ground wire inside, and shield connected to ground only on ECU side). Than only try the factory harness when it works well with the separate shielded cable so you have a good starting point reference.


Ideas - setting up more agressive filtering for this low toothcount


Subaru_1.jpg

New Vems pcb installed

Subaru_2.jpg

Our technical engineer trying to hunt down the errors

Subaru_3.jpg

Test car 600 Hp HKS Subaru