HEGO Transport Delay

[red]

In Advantage III, there are scalar variables under the O2 Sensor category for transport delay learning including ones defining bounds in load, RPM, seconds, etc. Moving the location of the O2 further away (e.g., after installing long tube headers) increases the amount of transport delay, creating positive feedback and causing oscillation/hunting around stoich, which can effect learned fuel trims. Has anyone experimented or otherwise determined whether the transport delay learning is functional in our cars? If it is, is it unnecessary to modify the transport delay table after moving the HEGO location?

[TooManyFords]

In Advantage III, there are scalar variables under the O2 Sensor category for transport delay learning including ones defining bounds in load, RPM, seconds, etc. Moving the location of the O2 further away (e.g., after installing long tube headers) increases the amount of transport delay, creating positive feedback and causing oscillation/hunting around stoich, which can effect learned fuel trims. Has anyone experimented or otherwise determined whether the transport delay learning is functional in our cars? If it is, is it unnecessary to modify the transport delay table after moving the HEGO location?

Yes, and you should adjust it upwards for headers. I think I multiplied mine by 1.25 for the Kooks and it did not hunt.

John

[red]

Yes, and you should adjust it upwards for headers. I think I multiplied mine by 1.25 for the Kooks and it did not hunt.
Thanks for the reply, John. Specifically, I was asking about the HEGO transport delay learning parameters, whether our car by default learns changes, and what the intended purpose is (e.g., minor corrections to the transport delay table). Also, I'm curious if it is capable of correcting for a change as big as HEGO relocation. Have you adjusted these variables in the past?

Concerning your changes, did you look at your trims before and after modifying the transport delay to observe the difference? Thanks!

[TooManyFords]

I am not going to be able to answer that, red. Now that I've switched to a BigStuff3 I do not use my SCT ProRacer anymore. Maybe I should sell it....

Also, I may have this confused with the delay for the O2 sensor to prevent a lean spike that can be corrected by telling the software now much further away it is from default.

John

[ImpalaSlayer]

is this something i should be concerned about being that im buying headers?

[red]

I am not going to be able to answer that, red. Now that I've switched to a BigStuff3 I do not use my SCT ProRacer anymore. Maybe I should sell it....
:cool:


Also, I may have this confused with the delay for the O2 sensor to prevent a lean spike that can be corrected by telling the software now much further away it is from default.
What you describe is the transport delay. In closed loop, the hunting will cause overcompensation (rich and lean), but I don't know how the transport delay learning adjusts or corrects for this problem. Also, if hunting occurs, I don't know whether (or how) the fuel trims would be affected (i.e., how they'd adapt over time). I guess this depends on how the computer samples, averages, etc. Any thoughts?