Injector Flow Modifier IAT

Hi Everyone

I have a LS1 with a 1BAR SD that I'm trying to fine tune and I'm curious how achieve steady AFR's during any IAT.

I know in EFI Live there's an Injector Flor Modifier IAT table for the E38 ECU but I can't find any guide any post about how to achieve a steady AFR?

The car has to stay open loop because due to the size of the cam the 02 switching causes the rpm to fluctuate.

All the tables that I can find reference to ECT.


Any help would be appreciated.


Thank you all.

If your AFR varies with IAT then you need to be looking at the cylinder charge bias table - there's no IAT modifier like EFILive. There is a PE Adder vs IAT which I commonly populate depending on intake tract and setup.

That said, as long as your IAT is as close as representative of the air being ingested by the engine as possible then your AFR shouldn't vary too wildly.

To generalise my findings with bias. It needs to be closer to equality of ECT/IAT at low and high airflows that GM typically inputs noting that it varies with OS i.e. numbers closer to 1 with an decay towards around 0.5 as airflows increase. It really does depend as you're trying to solve a variable with a variable. Gotta make some assumptions to achieve that.

There is a flow rate vs IAT modifier, but it's there to be a safety feature, ie as iats get high there's more fuel injected to cool the charge better so there's no BOOM. If you're fueling is varying significantly with temperature changes then you need to adjust your bias table as SSUte said. Or put the MAF back on it.

Hrmm Ok, thanks guys for your feedback.

So I get the Cylinder Charge Bias Table.

I haven't quite got the hang of the histograms. I'm wondering how to build the PE Adder Vs IAT table from using the logs?

I'm thinking something along the lines of logging my WB, IAT, and CMD AFR and then somehow making it map to the PE Adder Vs IAT table to show me how much the AFR's were out.

What would be magic if that histogram could show me what exact EQ Ratio Adder value to add to this table.

Any ideas guys?

Thank you.