Question on Fuel Scale and Latency

Hey everyone,

Say my trims are consistently removing 5% fuel...

therefore to maintain a Lambda of 1.00 I would need to either REMOVE 5% from the injector flow scale OR a 5% DECREASE in the injector latency. These values are directly proportional to one another, Correct?

Latency as per manufacturer data. Latency is the time the injector is not spraying fuel due to pintle weight and time needed to build up the magnetic field force.

What ECU is this?

Modelled or time based injection fuel model?

You could remove 5% from either, the fuel table, master fuel number, or add 5% to injector flow settings.

All areas of the fuel map need to be accessed / measured subsequently, in order to make sure mixture is how it is supposed to be.

Expect to having to apply corrections accordingly.

Injector latency results in a time offset, Injector scale is a time multiplier. 5% is a multiplier, so you should only apply that to the scale, not the latency.

Changing just scale 5 percent not always results in changing the fuel trim to the same percentage as there are quite a few additional parameters that affect on final injector pulse width but should bring you closer to required ballpark...

How are you determining which one you should be adjusting?

Usually flow rate is known, sometimes injector latency is not known. If all other factors are known, then adjusting a single unknown factor seems the best option.

Mike, if that question is to me- sure you change scaling to adjust fuel trims. What i was saying it's not always exact as asked in the top message. Sometimes it's very close but not exact because of other variables such as engine coolant temp, specific fuel density, intake heat soaking that might play a small role in changing the fuel trim also.

Sorry, I was asking the original poster, but I'm sure they'll appreciate your additional info!