TBI ignition control module

[Fast355]

How can you accurately say "with no knowledge"?

I can accurately state, you don't know everything!

dave w

I never claimed to know everything, but I do have a fair working knowledge of what the bias values do in the code and also what happens when someone just zeros them out. I have been through the actual code in the motorola assembler and dissasembler as well as worked in the $0D Hac enough to make my own XDF and write my own lines of code in $OD. I also have a fair knowledge of the workings of the MAF OD and MAF OD MPFI code. The datalog is doing those weird numbers because the timing advance is negative in those areas. As soon as the timing value is positive the weird mess goes away. That is why whacking the altitude bias appears to fix it. It is doing the same thing as offsetting the whole timing map the same number of degrees advanced. The bias is simply there so that the table can have a negative number. Guys used to ignore the bias value and several $42 ecu and xdf files were written without the bias value being subtracted out.

Long story short, leave the bias alone, make the timing map positive, make sure the coolant xompensation is not retarding a ton of timing at the coolant temp the engine is running and that there is no knock retard and those weird values will go away. If the engine actually needs negative timing there, simply know that those weird numbers are negative timing values.