No secondary trigger audi 5cyl

[snaak]

Hi,

I am new to VEMS so forgive me if I ask silly questions 

I installed VEMS pnp for audi on mij RS2. I installed the newest firmware and a standard audi config (with cam hall inverter) out of vemstune. When I make a triggelog the secondary trigger does not show at all. I installed a 7a flywheel and know of the triggered problems with the (small) crank home pin. I tried to bring the sensor closer to the pin, with no result. The car fires right up when I hook up the motronic so the cam-hall sensor should be OK.
Thanx!

[Erikk]

Did you swap the pins in the connector for the secondary VR sensor (home-pin) ?

Trigger

The secondary trigger crankhome-VR MUST BE reversed. Can be done in the connector on the firewall.

Measure trigger resistance against AANpin48.

... Ohm between 49 and 48 (135 cranktooth-VR primary trigger)
... Ohm between 47 and 48 (crankhome-VR secondary trigger)
Reversing crankhome-VR polarity

Disconnect the crankhome-VR secondary trigger (3 pin AMP connector at the firewall. Was black in our AAN harness). In the female connector:
measure with DVM which of the 3 pins go to motronic AAN pin48 (this is trigger GND)
measure with DVM which of the 3 pins go to motronic AAN pin47 (crankhome-VR secondary trigger. The 3B engine-harness pinout is different: 3Bpin49 !!!)
measure resistance between pin 1 and 2 in the 3pin male connector (of the sensor). You should get the same Ohm as above (eg. 980 Ohm, or 1010 Ohm or around that)
swap the 2 wires in the female connector (red and violet in our case)
if you cannot pull out the receptacles, than you need to cut, blank, solder and insulate
mate the crankhome-VR secondary trigger 3pin connector (male in the female :-)
do the measurement in the motronic pins, ... Ohm between 47 and 48 : it should still be the same (the ohm measurement is polarity independent)
Location of the trigger plug:



Wiring crank home normal:



Swap the red and violet wire:



The wire is swapped:

[snaak]

Yes, I use the adapter cable that comes with the VEMS

[Erikk]

To test the crank-home signal, you can pull the hall-sensor connector and make a short between 5v and signal, that way you will pickup a camsync signal everytime the crankhome pin goes by the secondary vr-sensor.
If you get signal when testing this, your crankhome pin isnt alligned with the hallsensor-window.

Operation with failed cam-HALL sensor ("limp-home")

The factory audi cam-HALL sensor is known to break relatively often, especially old (original) sensor in an overheated engine bay, especially the sensor in the distributer (the sensor at the front, as in some engines, seem to fail less often). We've seen small unipolar HALL-sensor [SS443A] hacked into the distributer but we don't know how difficult it is to apply it reliably.

The motronic cannot start with a failed HALL sensor. VEMS can start with failed HALL sensor, appr. 50% of the time (need to crank a few more time if backfires), if:

(with cam-HALL inverter, which is standard now, with trigger_tooth=00) the HALL pin is pulled to ground. In other words, to limp-home to the car-electrician, find the pin in the HALL connector that is the +5V from ECU, and connect the other 2 pins
without cam-HALL inverter (which used to be standard before 2008-06, with trigger_tooth=08) the HALL pin is pulled to +5V (simply disconnect the sensor connector; note that with some luck the HALL sensor will fail with output stuck to +5V or open circuit).

[snaak]

If I read correctly I should connect the other 2 wires, not the 5V wire, I did that and still no signal.