Exhaust pulse delay

Definition: the time in miliseconds from fuel pulse calculation till it should register at the O2 sensors.

Platform:

Min Value:If headers are not ceramic/jet-hot coated =13-14,

Max Value:If they are =11-12

Description: Increase the numbers higher for long tube headers. Changes the injector timing calculations.

Hints:

This is the amount of time in engine revolutions that it takes the exhaust charge to reach the oxygen sensor after ignition. Increase this value to improve idle on cars with long tube headers.
Here is a more specific definition contributed from a someone in the EEC-EFI mailing list:

Exhaust pulse delay is the time between when the injector pulse width is calculated in the EEC (*not* when the injector is fired), to when that pulse ends up reliably sensed at the HEGO sensor. This is used to predict when the O2 signal will cross so it can get the correct amplitude and bias results." From an EEC Tuner user point of view, longer headers mean larger values in the table. Conceivably, changing the injector timing table could also have any effect here (I would presume only a negligible one though.
RPM
Load (VE) 700 900 1950 3000
0.05 (5%) 10 10 10 10
0.10 (10% 10 10 10 10
0.20 (20%) 10 10 10 10
0.30 (30%) 10 10 10 10
0.40 (40%) 10 10 10 10
0.50 (50%) 10 10 10 10
0.60 (60%) 10 10 10 10
0.75 (75%) 10 10 10 10



See Also:
Emissions Table load scaling
Emissions table RPM scaling