Fuel Economy Tuning Ideas

[SUTTERERMAN85]

You need to look at the General Airflow vs Mode & determine where you are currently vs MAF airflow in g/sec.

I like to leave the top points where they are (Mode 12,14, & 16) or richen them (~526) to keep the AFR around 14.4 in closed loop at higher airflows. You don't need it really rich just slightly richer there.

If you are idling in closed loop and see the AFR is in the 15's or greater you need to adjust the lowest mode values. I find with cammed cars that roughly ~526 works nice. There are upper & lower limits (not accessed in HPT) that will prevent you from GTF'ing it (Gone TOO Far) so if you keep changing the value & nothing happens you've GTF'd it.

The General Airflow vs Mode values I have there should be OK for your application. They are just guidelines though. If you have a heavy truck with 44's on it, nothing will help .

EC

well thank you very much. i am a noob at this so any info helps. its really nice you guys on here that are willing yo help new guys out. soundengineer is another one that has helped me already also. thanks alot guys. im sure i will have more q's and will prob talk again with you guys hope you dont mind oh ya its a cammed camaro with a G5X1 in it

[Blacker]

sens.112 is extremely important....Injector Pulse Width in milleseconds

if its not working then you are missing something while logging
must log all of those parameters...

I have an updated one now too..takes into account IAT and ECT..

[SENS.20]/(([PID.6210]*0.132276)*[SENS.112]*[SENS.70]*8/(6175*(((([SENS.11]+[sens.10])/2)+273.15)/299.8167)))

this should get you MPG..and should compensate a little for fuel temperature a little bit..cause fuel weighs different amounts at different temperatures

seems to be accurate in my car...
works perfect..last 4 tanks have been all within .5 of dead on for me...

basically its
[MPH]/(([Injector Flow Rate]*0.132276)*[InjectorPulse Width]*[RPM]*8/(6175*(((([IAT]+[ECT])/2)+273.15)/299.8167)))

with everything converted so that the units match appropriately

You Must Log:
Vehicle SPEED
Injector Flow Rate
Injector Pulse Width
Engine SPEED
IAT
ECT

Scott:

Tried your new equation and works like a champ I actually average 27.7mpg on the way to work.

[S2H]

Scott:

Tried your new equation and works like a champ I actually average 27.7mpg on the way to work.

now does it actually jive with what you have been averaging from your tank fillups???

I dont expect the equation to be perfect..but it should be reasonably close

[Blacker]

now does it actually jive with what you have been averaging from your tank fillups???

I dont expect the equation to be perfect..but it should be reasonably close

I seems close. I have only tried it on the way to work and back. I was getting ~21mpg with all highway time. While I was on the highway while going to work, the histogram was 21.29 mpg. My average spiked because of DFCO while slowing down for the exit and the average went to 27 mpg.

[S2H]

IF it spiked that far then you must not have had a long drive to work.LOL
I drive about an hour each way to work and home..so for me it was dead on because I had a lot of data as well...

[jjnada]

Just an update. I've had several fill-ups since my last post, and I wanted to chart my mpg in excel, but cant seem to find some receipts (I calc my mpg every fill up and write it on the receipt).

In any case, here's my last three: 26.3mpg, 26.4mpg, 23.8mpg. That last one really stands out but its still far better than before the mod. And as far as the lost receipts go, three of them had mpgs in the 26s and one was in the 25s. I'll post those if they show up and maybe see if I can put together a spreadsheet.

[Billf6531]

Any recommended DFCO settings for Enable RPM vs. Gear?

[SUTTERERMAN85]

how about where to start turning on DFCO. i have no idea where to begin???

[PurplePiss]

My settings are:

Enable temp 86
Disable temp 77
enable rpm 700
disable rpm 705
enable speed - all 10
disable speed - all 9's.

Comments on those settings?

Do you have to run open loop to do this pseudo lean cruise? Can someone lay it out in detail what your doing, cause I'm lost and apparently I'm not the only one.

[EC_Tune]

The settings aren't there yet in the 05-06 car LS2/LS7's yet. I'm guessing the setup is different though as the new ECM's use more math for calculations.

EC

[kabbott]

With no "lean cruise" and no O2 switchpoints(I got a v6) could I use my WB to sim NB O2's and setup the crossover point somewhere above 14.7 to "fool engine" into thinking its running at 14.7?
I know this would lean out everything but PE could still be tuned correctly.
Anyone see problems with this and just how lean can one go safely at cruise?
Thinking about trying this to sqeeze some more MPG.

[strider]

I am only running a 2.2L on my cavalier. But when I turned off the torque management my cruise control downshifted about 20% less of the time when climbing the hills. I am on the highway about 80% of the time and it resulted in a 3-5% fuel saving.

[kabbott]

OK that idea didnt pan out to good......BUT when using WB to sim NB output on my v6 , since i only have one O2 sens , does work nicely to make fuel trims come in line with WB when I put it back in closed loop.
Kinda like a poor mans O2 switchpoints

[BAD LS1]

Whats is the suggestion for trying to tune the LS4 5.3L?

The computer doesnt have the option to set "closed loop vs air flow" etc etc...

Attached is my MC-SS's file. Can anyone make a sugestion of what to tweak?

I found the exact location on my Camaro's file... but thats a older PCM.

The DFCO table operates the DOD for these cars too, i played with that a bit already too... just makes it hang out in 4 cyl mode a touch longer


Thanks!

Must have V 2.12 to open the below file.

[98A4LS1]

sens.112 is extremely important....Injector Pulse Width in milleseconds

if its not working then you are missing something while logging
must log all of those parameters...

I have an updated one now too..takes into account IAT and ECT..

[SENS.20]/(([PID.6210]*0.132276)*[SENS.112]*[SENS.70]*8/(6175*(((([SENS.11]+[sens.10])/2)+273.15)/299.8167)))

this should get you MPG..and should compensate a little for fuel temperature a little bit..cause fuel weighs different amounts at different temperatures

seems to be accurate in my car...
works perfect..last 4 tanks have been all within .5 of dead on for me...

basically its
[MPH]/(([Injector Flow Rate]*0.132276)*[InjectorPulse Width]*[RPM]*8/(6175*(((([IAT]+[ECT])/2)+273.15)/299.8167)))

with everything converted so that the units match appropriately

You Must Log:
Vehicle SPEED
Injector Flow Rate
Injector Pulse Width
Engine SPEED
IAT
ECT

I tried this yesterday and I'm getting 14.1 at 60 mph cruising steady on interstate assuming I did everything correctly. 5.9 mpg at idle. Does this sound right?
This would explain my poor gas mileage. In building the custom histogram I selected "gal" as units.
I have fresh O2 sensors, spark plugs and plug wires. My LTFT's are -1 to 6 everywhere. Any ideas?

[S2H]

I tried this yesterday and I'm getting 14.1 at 60 mph cruising steady on interstate assuming I did everything correctly. 5.9 mpg at idle. Does this sound right?
This would explain my poor gas mileage. In building the custom histogram I selected "gal" as units.
I have fresh O2 sensors, spark plugs and plug wires. My LTFT's are -1 to 6 everywhere. Any ideas?

post yoru log and I can tell you what you might have missed..
you should be seeing 0 mpg at idle..LOL...not moving=0mpg

[98A4LS1]

post yoru log and I can tell you what you might have missed..
you should be seeing 0 mpg at idle..LOL...not moving=0mpg

I'll try to post a log today. My bad, it was "0" at idle. LOL.

[98A4LS1]

Here is the first attempt with custom PID for mpg.

[S2H]

it looks like you have the right things

got a whole whopping 13 mpg on that file...LOL

you're gonna have to learn how to keep your foot ot of it of you want better MPG...

[98A4LS1]

Foot out of it? Look at the RPMs and % throttle! I was steady cruising at 60 mph and < 2000 rpm.