Car is my friends '86 928 S with 4.7litre V8, Strosek body kit and ultra-wide Folger 18inch wheels. Engine produces 310hp stock.
This is the beast:
Car is running very well right now.
It had LH-Jetronic from the factory. LH was fuel only, spark was distributed by two(!) 4cylinder dizzys! I threw old engine compartment wiring off and applied 8 VW COP ignition coil.
Car has 100-1 tooth wheel on the flywheel with VR sensor.
Redline RPM: 7000rpm
Overlapping dwell firmware will be needed for this (1.0.60 or 1.0.61 or later, though we do further tests on table and other tuned engines). With 100-1 trigger wheel and old firmware it seems to lose teeth above appr 6000 RPM (=> wheel error => cutting spark => misfires, resulting loud backfiring through the exaust). The overlapping dwell firmware pushes the limit beyond 1 million tooth per minute for N-1/N-2 (>10000 RPM with 100-1 wheel, >16666 RPM with 60-2 and >20000 RPM for lower N). The InputTrigger/AudiTrigger is not N-1 (uses a different handler), so 135 tooth allows > 10000 RPM there. If necessary (which I doubt), these RPMs can be pushed further, since the average CPU load allows 3..5 times higher, just the longest branch can be split to allow even higher tooth-frequency.
- VR sensor; after some tweaking I got steady rpm signal without trigger errors. (On cranking and low rpms, there are no wheel errors).
- separate page for ignition: MembersPage/PeepPaadam/PorscheIgnition
COPS
- VAG part number 036 905 715 A
- It turned out that the owner gave me wrong pinouts for the COPs (this prevented operation for a while); when I found out about it and fixed it by swapping two pins, I got good spark immediately at the plug!
I measured the resistance between pins.
it's like that: Between pin 1 and 4 = 390 ohms, between pin 3 and both 1 and 4 40kOhm and betweens pins 3 and 2 16kOhms.
Correct pinout is like this: pin1 & 2 - GND, pin3- +12V supply, pin4- Signal
26.09.06 - old speculation (the COPs were connected according to bad pinout => no spark
Got the wiring done and since I have two of the 8 COPs needed, i thought I'd try to get a spark on the plug. Ok, got everything hooked up correctly and I set dwell to 3ms, cranked and.....Nothing!
Disconnected the coil and measured (how? what equipment ? what settings ?) the output of Genboard while cranking, it was something like 1.2-1.3 volts for a second and then dropped to 0.08-0.1 volts.
If you measure with a DVM in DC mode, that measures mean voltage. Eg. 5V, 20% of the time (80% off) measures 1V. Yes, I measured DC voltage, appr 1V, so it's all ok then.
- Check InputTrigger/TriggerLog ... maybe no need if no wheel errors and RPM steady
- MegaTune log is often useful
- config and tables for this car: MembersPage/PeepPaadam/Config_Tables
- config looks like wasted spark setup. I'd start the car with wasted spark coilpack, and only move to COP later.
- check if the right outputs are selected
- make sure there is fuse protection for each ignition transformer (3A per transformer; if it's only possible to fuse them paired, than 5A; use 7.5A if fuse powers 4 channels; use 10A if fuse powers 8 channels, but use more fuses if possible, that is always possible with COPs).
- use mdn03 (mdn02, mdn01, mdn00) to fire small spark (make some sparkgap - not necesserily from sparkplug - outside the engine so you can see; make sure the total gap is sufficient, eg. end of stripped wire 1mm from block ).