Repair Active Fuel management for just a few pennies DIY fix.

[bg1988]

This is not DIY in Oregon or New Jersey ..    haha  

 

 

GAS QUALITY effects on how your  AFM works 

 

garbage GAS  fudges up the ECM  and it will rapidly shift between v4 and v8 mode causing damage to the system...or excessive wear and tear...

 

if you all ready have "excessive wear and tear"  it's too late...

 

Also your transmission will be searching for gears less often as well using 91/93 oct..

you get to stay in a higher gear longer 

 

 

 

 

i have tested varies gas station brands and octanes as well.. i have came to the conclusion that these two BRANDS of fuel WORK the BEST!!  on AFM engines..

 

 

 

Chevron/Texaco/CalTex

91 or 93 Octane 

 and

Mobil/Exxon  

91 or 93 Octane 

 

WILL work the BEST with the AFM system  both brands are tied #1 spot for a fully functional AFM system..

 

 

brands that cause the excessive  rapid shifting or dysfunctional/ non-functional AFM system include

 

using 91oct

 

Shell 

Arco/BP  

Marathon/USA gas

[Insert Name of your Cheap Gas Station Here]

[swathdiver]

My experience as well, Chevron/Texaco is tops, then Exxon/Mobil.

[Bob2C]

Interesting you say that. I did away with AFM using the Range device.. Let me tell you the truck is more responsive, but back to this topic. I just filled up with BJ's gas (87)and it runs like crap.  Exxon made it run smoother on 87. I will try 91 Exxon after I run through the crap I have in there.

[tbarn]

Between my '14, '15 and '18, I've run Mobil, Shell, Kwik Trip, Casey's BP and probably more. All 87 octane. All three trucks ran/run perfectly.

[Colossus]

The Costco 91 octane has done will thus far.  It is Top tier as well. 

[swathdiver]

1 hour ago, tbarn said:

Between my '14, '15 and '18, I've run Mobil, Shell, Kwik Trip, Casey's BP and probably more. All 87 octane. All three trucks ran/run perfectly.

The DI motors seem less influenced by lower quality fuels.  Besides, the L83 makes a lot more horsepower per cylinder compared with the Gen IV 5.3s and so can run in AFM mode about 50% of the time whereas the older generation was about 10%.  4-5 horsepower per cylinder difference is a lot.  Even more torque.

[flyingfool]

Techron Gas is gold.. I use it in dirtbikes, cause the additives in the fuel last forever. I can fill up a bike tank with 91 Techron, 6-7 months later its still good and clear, not oxidized or yellowing into shellac. TEchron #1!!!

[Colossus]

Yes.  Techron is some of the best fuel system cleaner additives out there. 

[bg1988]

the proof is in the gas mileage  I wanted a SUV but also wanted good MPG ,  hitting over 28.9MPG with the 6.0L (W/Hybrid Module) ...

 

 AFM works all the way upto 1900RPM or 80MPH  that is how I get the good MPG. with the good fuel  and octane..

 

 

Small cars are pretty useless where i live  since our speed limits are very high and if you get hit at 45 -60MPH your dead in a car.. or hurt pretty bad aka: a vegetable.  I have seen some pretty nasty crashes  like a 1996 tahoe hit a  1994 honda accord  the people in the accord got ejected.(dead).  they were hit at 55MPH.. T-Boned  they did lower the speed limit to 45mph  afterwards  but tooo late

 

also btw the tahoe just need a new front clip and it was ready to hit the road again 

Edited July 3, 2019 by bg1988

[flyingfool]

octane definatly improves mpg, on our truck I've found no gain after 89 octane, no mpg improvements with 91 octane .  87 is horrible milage 12mpg

[sefiroxx]

Mfg set tuning curves per usage, buyer, intent. So, staying at the peak of the curve (ie 87-89) allows for max mpg.

But when you get away from the peak, things can get iffy and requires manual adjustments or parts upgrade.

On my Cadillacs, we ran a number of long term tests at various octanes with and without simple adjustments (ie timing). But in the end, the best $/mile was the spec of mfg. (Ie spec at 91, but 89 or 87 would have a mpg drop that cost more than the savings on price per gallon.

[carnau]

On 7/1/2019 at 11:03 PM, tbarn said:

Between my '14, '15 and '18, I've run Mobil, Shell, Kwik Trip, Casey's BP and probably more. All 87 octane. All three trucks ran/run perfectly.

You have not had any injector problems? That's the only issue we ever see with 14- 19 trucks. It's not the fuel you use, but the placement of the injector.

[tbarn]

No injector issues. Been retired for a year now but saw more issues with 6.2 injectors for some reason. My  trucks were all 5.3's.

Edited July 6, 2019 by tbarn