MSefi.com read only forum (Jan.15,2018)

i have aquestion about the reading
of the LC-1 and MegaSquirt
look i have diferentes Reading
between the LC-1 gauge and the MegaSquirt
for example in the LC-1 gauge i have 10.0AFR and the MegaSquirt Have 12.9 AFR
why ?

Check your grounding. Everything should have an individual ground wire and go to the same grounding point, preferably on the engine block.

If you have the MS and the LC1 grounded at different points, the difference in "ground" potential can be a volt or more, that's likely what's throwing off your AFR readings in the MS.

Also check what LC1 you set it up as in MegaTune. There are a couple of LC1 options, primarily the :
LC1 Default that is 0-5V, 7.35:1 -22.05:1
and the commonly used:
Innovate LC1, PLX 0-5V 10:1-20:1

If you haven't reprogrammed your LC1, you should stick with the LC1 Default.