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MembersPage/JuhaK (2005-12-29 02:00:01)

My plan is to make the RadioBoard to be real, look also VemsFrontier/Bluetooth

I got Volvo Amazon with B20.

36-1 toothwheel

I mounted a 36-1 toothwheel to crank from Ford (it's like [this]) and Honeywell GT1 hall sensor. It did work when rotating crank manually, but engine didn't start. I get back to coil-type trigger, started the engine and looked hall sensor signal with scope. Scope showed that signal was lost when sensor was near the trigger wheel and it did work somehow when distance was out-of-GT1-specs, 4-5mm, but there was still few errors. I tried hall as primary trigger when distance was 4-5mm, but LCD showed Wxx growing all the time.

Jörgen told that the trigger wheel was not suitable for GT sensor; "But I have used the GT sensor a lot and have used it far outside it's specifications with good and bad results. What I do know is that the sensor is self adjusting, you'll notice this if you put a piece of steel in front of it at 1mm distance and then move it to 7mm distance. It will go high for a while and then selfadjust to see the steel again"

"I think this is what happens with the trigger wheel you have, it sees the solid disk for some reason, probably because there is not enough material in the trigger teeth. Moving the sensor further from the solid disk in the axial direction (of the crank) could help."

"If you choose to make a new triggerwheel you should know that the GT1 sensor does not work well with trigger made up of large raised areas with smaller lower areas as a trigger wheel made by drilling holes. This is because of the self adjusting feature."

Because I did weld ford toothwheel to crank pulley I did try another hall-sensor, made by Hamlin. New hall sensor did work and now my GenBoard/VerTwo is trigged from 36-1 toothwheel and it's controlling both, fuel and a single-coil (distributor) spark with IGBT.\n

primary_trigger=01 # multitooth (rising edge at the processor)
secondary_trigger=02 # Cam sync disabled
trigger_tooth=01 # 01*10 degrees after when the missing tooth is detected
tooth_wheel=23 # 36-1, 35 tooth
another_trigger_tooth=12 # also fire 18 teeth (180 degrees) later than trigger_tooth (for 36-1 wheel)

crank_minper=40 # anything from 01 to 50 is fine. If measured event-period (that is every 180degrees for a 4-cyl) is shorter than this, it's considered and error.
tooth_wheel_twidth1=0A # Tooth is 10 engphase units
tooth_wheel_twidth2=14 # Missing tooth is 20 engphase units
reset_engphase_after=D8 # 216 engphase units

1 trigger pulse per crankrot

D-jetronic distributor has 2 evenly spaced extra triggers without advance. Using only one of them I could get good secondary (cam) trigger. These triggers are ~80-90 crankdegrees before TDC (one 80-90 degrees before cyl 1 and other one 80-90 degrees before cyl 4). If these triggers are connected in parallel there would be 1 trigger pulse per crankrotation. If they would be used as primary trigger it is needed to calculate other trigger pulse in SW, which would be 180 crankdegrees later.

There is no config to support coil setup sparking twice for every trigger-pulse.

Q: It would be possible to make it work in SW, but do you think it would be too unaccurate? (This is just brainstorming an (stupid) idea!)

  • I think it would be too inaccurate, too many too early sparks at cranking and the code wouldn't be used: it just doesn't worth the effort.

Bosch wasted spark coil

What do you think about this [Bosch wasted-spark coil]? It's pretty cheap (~70 euros here!), but hard (?) to find from a junkyard. Seems like a good transformer.

I cannot understand the dwell(VBatt) function. Maybe I should calc with the i(t) = VBatt/R * ( 1 - e**(-t*L/R)) to see if they match Bosch values (R=0.5 Ohm, L=3.7mH for coil primary).

Trigger problems when cold

My GenBoard/VerTwo has 36-1 hall type trigger, it has run 1.0.12 all summer and worked fine! Now when engine hasn't been warmed up with electric and it's cold outside (-10 to -20'c) the car does not want to start at all, only trigger errors (Wxx grows very quicly on lcd, even when cranking with no fuel, throttle at floor = flood clear). I have primary_trigger=01, crank_minper=0x32 (tried 0..0x80, did not help). Engine has 5w-40 oil, but it's an old Volvo engine so starter isn't giving very stable rpm. I did make a short log with megatune, it showed rpm bouncing from normal ~100 to 65535 (or max anyway) while cranking. Engine does work after it's been warming sometime!

SO what do you think guys. Is it all about hall sensor distance from triggerwheel? Or is it voltage drops? Hall is supplied from TPS5v, so if voltage drops GenBoard/VerTwo should have several resets too, but it doesnt! Or is it just my engine revving so unstable while cold crank that genboard just can't handle that bad signal?

I did upgrade to 1.0.25 just few days ago, it worked fine. Cold weather begin few days later, so did my problems. I did downgrade back to good old 1.0.12 with its confings, but this problem has nothing to do with firmware. I did try 1.0.25 new advanced filter with 0x8A and 0x00, primary_trigger=09. Also tried primary_trigger=05 (filtered). Either didn't help.

How low is your RPM ?

What is trig2spark value ? (trig2spark=ign_tdcdelay - ignadv). Try to use a later trigger_tooth and decrease ign_tdcdelay accordingly (down to 48..50 degrees). This will enable a lower RPM. However, if there are trigger wheel errors, this won't help. Maybe InputTrigger/TriggerLog would reveal something.