First start, and COP question

[Lizard]

Hello Gents,

I am doing an initial start on a 1987 928S4 turbo.

VEMS V3.6
Serial 3634
PS2: Y
IGBT: 0
Firmware: 1.2.4
VEMSTune V 1.3.1 (2012.07.30)

This is the second VEMS unit that I have setup, but the last was iirc in 2009, so its been awhile. Unfortunately I do not have the other car handy to be able to confirm the information I'm wanting to confirm off it.

The COP units I am running are for a Cayenne, they are logic level COP units, but they require 350mA in the logic line to turn on. I had issues with this on the first car too, and on a MS car that I have done with them too.
Now on the MS car, I just added a 240ohm resistor to +12V for pullup, this worked very well.
The prior car, I ended up having to run the ign coils off the Stepper outputs and then they worked perfectly. But I'm really wanting to get the ign circuits working.
Now, will the transistor that is firing the logic level outputs handle a 240ohm pullup resistor to give me the needed current?

The other question I have is regarding the trigger. Using factory VR sensor and trigger wheel.
it is 60-2
the missing teeth are 60 deg BTDC.
Running them in dual channel (wasted spark), until I figure out the cam sensor.
So I have wired them as per the wiring order, and the brain to be able to do 0+1, 2+3, 4+5, 6+7 and have set that up in Ign settings to fire in 0, 7,6,5,4,3,2,1

So I have 58 teeth,
TDC after the trigger at 60
first trigger tooth 0
next trigger tooth (distance) 15
angular width of tooth 6 deg.

Does anyone see anything wrong with those settings?

TIA
Colin J

[Lizard]

Well, I couldnt wait, I hooked it up and tried to start it.

I'm seeing what appears to be proper RPM on the tach, so I think the toothed wheel is correct.

However the coils are not firing at all with the pullup resistors.
I then disconnected the line feeding the pullups (though left resistors in there),
I then swapped them over to the stepper ABCD, wiring them in order so I have 00a,03b,02c,03d

I am now seeing a small flicker on my COP tester every few rotations. But I am thinking I still do not have enough spark to fire.
So I need to confirm the settings for the COP units.

These units require a +5V (work fine on +12V) signal line with a max dwell of 1.9mS, I was wrong on the amp requirement for the coils. The logic line going in requires a minimum of 18mA in the signal line to energize.
A PDF for the Cayenne COPs can hopefully be seen here https://gator1823.hostgator.com:2083/frontend/x3/filemanager/showfile.html?file=Cayenne+coil+info.pdf&fileop=&dir=%2Fhome%2Fcjensan%2FPDF&dirop=&charset=&file_charset=&baseurl=&basedir=

[PeepPaadam]

But why are you not seeing spark with logic level outputs? If you have the coils connected properly (firing order of 928 is 1-3-7-2-6-5-4-8, means 1+6, 3+5, 7+4, 2+8 should be connected to pairs) and you have verified the 1st cylinder TDC after the trigger position, it should start without issues.

Also, I would use 1.1.96 firmware, would not experiment with too fresh (un)releases...

The link you posted requires somesort of registration...

[Lizard]

well the reason it wasnt starting was my bad.
I had one of the switches to the relay run wrong. So it wasnt turning on the relay which supplied voltage to the coils, and injectors.
Fixed that and I got it to fire right up.

So now it is running (havent tried the ign circuits, still on stepper), I now need to move on to other things. Now needing to see if I can get the ISV to work.