Can I modify Active Fuel Mgt. with EFI Live?

[Patrick G]

I have a 2007 Suburban. I also have EFI Live with the V2 programmer and all the latest updates. Am I able to modify the Active Fuel Mgt. portion of my program? It's very difficult for the motor to stay in 4 cylinder mod unless I'm coasting or going downhill. Can I make it stay in 4 cylinder mode longer with EFI Live?

[ScarabEpic22]

I dont know, you probably can but is it really worth it? The guys I know with the 5.3L V8 in their TrailBlazer/Envoys have tuners completely disable DOD/AFM because it surges horribly once you tune them (ie take a perfect regular 5.3L tune and it surges horribly on a DOD/AFM one). You are only going to loose a little mileage, and if you do your tune right you will still be getting better mileage than before.

[Patrick G]

I agree with you about a good tune improving mileage. I had a very good tune in my 2002 Suburban that improved fuel economy. But, if a regular 5.3L tune surges horribly in a newer 5.3L AFM application, shouldn't that tune be modified somewhat?

Back to the original question: Does EFI Live have a provision to regulate how active fuel management/DOD comes on and off?

[kbracing96]

Why don't you pull the tune out of the truck and see what tables there are for it.

[GMPX]

We have had a number of Email requests to do this so I can add them in no problem. Currently we can only disable it totally.

Cheers,
Ross

[cme265]

We have had a number of Email requests to do this so I can add them in no problem. Currently we can only disable it totally.

Cheers,
Ross
sweeeeet..... you guys rock!!:master:

[Patrick G]

Thanks Ross,

I don't want to disable mine, I want it to work more often/better. With my new tune, the fuel economy has picked up overall, but I have a feeling that GM was way too conservative when they programmed the 4 cylinder mode. I don't see any reason why I should not be able to cruise on the highway on level ground in 4 cylinder mode. The way it is right now, it only goes in 4 cylinder mode on declines or upon decelleration. :mad:

[dfe1]

Thanks Ross,

I don't want to disable mine, I want it to work more often/better. With my new tune, the fuel economy has picked up overall, but I have a feeling that GM was way too conservative when they programmed the 4 cylinder mode. I don't see any reason why I should not be able to cruise on the highway on level ground in 4 cylinder mode. The way it is right now, it only goes in 4 cylinder mode on declines or upon decelleration. :mad:
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.

[ScarabEpic22]

If you can get tables to modify the DOD/AFM settings then it will most likely be worth it, but since you cant now the DOD settings were stock so they were just disabled.

[Patrick G]

I've received a beta cal file from Wait4me. It's pretty cool. I've been playing with the settings. They are not very intuitive and have taken lots of trial and error. I think I'm making a difference with the latest settings now. :cool:

[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,
RossI'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. :Eyecrazy:

[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