M800 & Ignition Expander

[killerbee]

M800 with an IEX operating 8 IGN1A coils. The coils have a built in TTL driver and test out fine when tested individually through the IEX's disconnected plug (change setup to single coil and drive one coil at a time in the test outputs screen). I then reconfigured the s/w for 8 individual coils and tried to set/confirm the CRIp with a timing light. What I found was that the timing light was not indicating the same timing position on the damper and sometimes seemed to flash flashing erratically. I went to a second timing light and got the same results. Details concerning the installation:
1. The ECU quickly achieves SYNC (mode 7, 60-2 trigger ref and Hall sync)
2. Cranks at 170 rpm
3. Well within the 500 mm wiring limit

I was wondering if the expander was messing with the dwell (LS1 IEX coil issue) and getting the coil to behave erratically. I have never installed and IEX before and followed the diagram A02 in doing the installation. I wasn't sure which of the grounds to use for the coil trigger ground and ended up using pins 20, 21 & 22.

I will be disconnecting the coil and review the signal to the coil from the IEX with a scope. I will also try to break out the signal from the m800 and the driving output from the IEX. This has the tendency to kill my battery and heat up the starter so it isn't the most convinient mode of testing. Are there any other ways to test the unit or is it just best to send it back to Motec ?

[RossB]

Are you setting the Ignition Type to "100" when you change from the single coil test to the IEX test?

When you are checking the CRIP make sure that you are not using a timing light with a dial back knob as this may not work properly.

Is your ECU an M880 (not M800)? The ground connections you refer to are for an M880.

[killerbee]

Ross:

The Ignition setup parameter is set to 100 when testing with the IEX. I have two timing lights and will make sure I am using the one w/o without an knob adjustment (although both seem to display the same erratic behavior). I was under the assumption that the coils had to be grounded back to the IEX. I gather that is not the case after looking at the Denso coil drawing. Should I just ground the coil's TTL back to the ECU ground ?

[killerbee]

To close things out I had grounded the TTL signal from the coils to grounds in the expander. As Ross noted that is not what these grounds are for. When I relocated these grounds to the ECU ground the timing/CRIP function was perfect. Thank You Ross !