Can I modify Active Fuel Mgt. with EFI Live?

[GMPX]

It was good timing actually, we had a shop that needed to do some testing with AFM / DOD shut off, so I needed to redo something in that section anyway. There is a lot of "if's" when it comes to AFM mode, but I think the tables we added should allow you to keep it in longer (or shorter) if needed. Please keep us updated as far as any MPG gains you might get now.

Cheers,
Ross

[Patrick G]

Ross, while the cal file that Wait4me sent me has tables I can manipulate, I'm not sure if they are doing anything. Jesse, if you can chime in, that would be great.

[mistermike]

The calibration in every DOD vehicle I've driven has been much too conservative in my opinion, so you're not alone in your thinking. Another problem I've found with some DOD calibrations is that before reverting to eight cylinder mode, the converter clutch is unlocked. I haven't seen that too much in trucks, but it's very noticable in some cars. In one case, an Impala SS, fuel economy indicated on the instantaneous monitor was actually worse in 4-cylinder mode than with all eight firing, (under the same operating conditions) because the converter was unlocked. I think you're in for a real treat when Ross adds the necessary tables.

Hmmm. Sounds like the tail wagging the dog a little bit. It would be nice to see how well we can really make DOD work. It sure beats GM having to ditch V8's in passenger vehicles to meet ever tighter CAFE standards. Don't you love it when Congress tries to legislate technology?

[GMPX]

Ross, while the cal file that Wait4me sent me has tables I can manipulate, I'm not sure if they are doing anything. Jesse, if you can chime in, that would be great.

The current release software does have some can PID's to log that shows the AFM status. This would be the best way to confrim your changes are working.

Cheers,
Ross

[Patrick G]

Ross,

The cal file that I received from Jesse Bubb does not have near as many parameters as what is available with other programs. There are TPS and rpm hysteresis parameters plus various timing parameters that are missing on my current cal file. Are these additional parameters necessary? If so, what is the time table for these to be added? I still have not received an answer from Jesse or anyone else on which way to skew the vacuum tables to allow AFM engage at higher kPa readings and stay engaged at higher kPa readings.

[GMPX]

What you really need to log is the PID - GM.AFM, it will show you when AFM is active. Whilst looking at those values also monitor the manifold pressure to get an idea on the values the ECM is enabling / disabling AFM.

If there is additional parameters that are needed we can certainly look in to adding them for another .cal file update.

Cheers,
Ross

[Patrick G]

What you really need to log is the PID - GM.AFM, it will show you when AFM is active. Whilst looking at those values also monitor the manifold pressure to get an idea on the values the ECM is enabling / disabling AFM.

If there is additional parameters that are needed we can certainly look in to adding them for another .cal file update.

Cheers,
Ross

I've been doing that Ross, but the changes to the vacuum enable/disable tables seem to be counter-intuitive. First, I changed my TSP max from 6% to 40%. Then I would raise the kPa readings of the enable table thinking this would allow me to engage at a higher kPa reading. This made it worse. So I lowered them. That helped, but not entirely. On the vacuum disengage table, it would seem that raising the kPa figure would keep it in AFM longer, but the opposite seemed to be true. Like I said, counter-intuitive. I wish somebody smarter than me would chime in and give me some help.

[GMPX]

Can you send me one of the log files? But, I'll need to see that PID GM.AFM included or else I'll just be flying blind.

Cheers,
Ross