MoTeC Global Forum

Hi all,
I am trying to get a Motec M4 working on a VW 8V 1.6L engine.
I have made a 60-2 wheel for the crank (with a Bosch Inductive sensor) and for SYNC I am using an old distributor with an inductive coil (an old Bosch prototype distributor) which has 3 of the 4 "pins" removed. The remaining one is used for SYNC signal. I have tried all combination of settings but I can not get the system to spark when cranking the engine. I always end up with "NO SYNC/SYNC ERROR". I have measured REF & SYNC signal in the harness connector (removed from the ECU), that is pin 6, pin 8 & pin 27. Pic from the oscilloscope is added as well as a screen dump from the "Main setup). Something is clearly wrong, but I can not understand where the problem is ......, so any suggestions are much appreciated!
(I have no problem getting spark and fuel injector when using the test function in the ECU, so I suspect no problems with the harness).

71 is set for rising sync and you have a fall edge.

Make sure yo have selected the correct edge for the REF as well.

Thanks for reply,
I changed the wiring for SYNC (kept REF as it is), removed sparkplugs (to increase cranking rpm and minimise rpm fluctuations). Still No Sync/Sync Error.
I am confused....

Is there anything metal near the sync sensor?
Are you using two core shielded wiring for REF & sync sensors?
Have you got the sensor 0V wired correctly?

In your second scope capture your sync is a rising edge and your ref is falling. You should be using ref/sync mode 73.

SprinterTRD wrote:Is there anything metal near the sync sensor?
Are you using two core shielded wiring for REF & sync sensors?
Have you got the sensor 0V wired correctly?

Here is a pic of the actual SYNC sensor (distributor):

I am using two core shielded wires from the ECU to its mating SYNC and REF connector.
As you perhaps can see in the pic, from the actual coil inside the distributor there are two "normal" wires (without shield) to its connector.
I am confident that I have wired 0V correct (to pin 27 (Sensor GND)).

I have decided (by excellent support from MoTec) to use these settings:
No of cyl: 24
Ref/Sync mode: 83
With these settings I was able to get coil firing during cranking, and thereby set correct Crip value.

For information, here is the latest SYNC sensor oscilloscope pic (after calibrating the scope):

I am still confused why I can't get it to work with this sensor (I have tried available sensor levels),
but I realise that I can not add more time to it - time to get the engine up and running

BTW, how much (and what) do I "loose" with a semi-sequential fuel injection compared to a fully sequential?

Regards
/Christian