LS1 with M84 only running on 4 cylinders

[Tom H]

Hi, my LS1 is only running on 4 cylinders, the timing order is 1 8 7 2 6 5 4 3, it runs wasted spark so 1+6 8+5 7+4 2+3 are grouped. The exhaust only gets hot for 1, 6, 2 and 3 (notice the link to the wasted spark groupings). I have used the check in the software to check the spark and injectors, and everything works when engine is not running, I checked the compression and this was all good and consistent. I checked the wiring to the coils and this is OK, ie no breaks. Based on the wasted spark groupings it looks like an ignition issue but I can't find it. I have changed the spark plugs, spark plug leads, and injectors. Any ideas?

[Scott@FP]

Both Injector and Ignition channels fire in sequential order from first firing event after missing tooth. Make sure wiring is correct. With 18726543 firing order injectors are wired cyl 1 =1, cyl 8 = 2, cyl 7 = 3, etc., same with ignition 1-6 = 1, cyl 8-5 = 2 etc.

Post cal file.

[Tom H]

thanks, I think the wiring is correct, I checked the wiring diagram against the actual wiring, all ok,
when I run the test output option under the utilities menu all the injectors and the spark plugs work as they should
I can't attach the config file as extension m84-12 is not allowed, any ideas?

[Tom H]

zipped version of the config file attached

[Scott@FP]

Only other thing I can suggest is verifying you are using the correct ref/sync mode for the cam/crank trigger setup you have installed.

Looks like the gen 3 24x crank trigger has special wiring and setup considerations-

viewtopic.php?f=11&t=356&p=1772&hilit=ls1+crip#p1772

[Tom H]

Thanks
The number of teeth on the crankshaft reluctor ring was set at 12 so I changed it to 24 as per the link supplied
This caused the the engine to backfire, run very roughly and it would not idle but all cylinders except 7 and 8 were firing
When the number of teeth is set at 12 it idles and run reasonably smoothly but on 4 cylinders as above

Any other ideas

[David Ferguson]

It really sounds like you have the ignition wiring in cylinder number order, not firing order. This is a common mistake for folks wiring a MoTeC for the first time. You can swap pins at the M84 connector to correct this.

[Tom H]

David
I have doubled checked the wiring and the timing order
The coils and injectors are all correct, I used the Test Outputs option under the Utilities menu

Can this be escalated to Motec? There must be other things to check

I did add code 19 to dig in 1 and this helped but still missing cylinders 7 and 8

Thanks
Tom

[SprinterTRD]

Sounds like you have wired the REF/sync incorrectly.

Which ref/sync mode have you used? Multy tooth (2) or the special LS mode (23)?

They require different ref/sync wiring.

[Tom H]

I'm using code 23, crank sensor going to ref/sync and cam sensor going to dig in 1

As per the motec T24 spec