GM AFM Disabler

[oldag]

My '06 without AFM usually gets better mpg than my '16 work truck with AFM. Both are 5.3's. But most of my driving is in 75 mph speed zones. So the AFM does not kick in even with cruise on. Apparently the '06 runs more efficiently on all eight than the '16 runs on all eight.

Where I notice the AFM is if AFM is engaged and I kick it in to pass. The lag is noticeable compared to non-AFM engines. Not severe, but noticeable.

Add: the '06 has about 230k miles now.

 

[pronstar]

08 Tahoe
149K miles

Got the dreaded ticking lifter noise.
Tried all the youtube quick remedies.
Nothing worked.

Brains is correct ... stripping an LS motor to the shortblock isn't a big deal. But I did the math ...

Cam, lifters, push rods, head bolts, gaskets, valley tray to remove AFM was $1200.

Then the might as wells surface.

Heads are off, should true them and replace seals.

Timing set of course.

Tackle that pesky oil pickup o-ring. While I'm here, replace the oil pump.

I'm not going back with the old water pump either.

Finally belts and hoses.

So now I'm close to $3k in and at the end of the day, I still have 150k motor.

So the question is ... do I trade it with an audible engine noise and take a bath or crate motor it and drive it for 5 years?

I installed a GM crate motor AND a range module.


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I’d put a crate in it.
Why the 5-year timeframe?
It should run well beyond that.


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[sidebite252]

I’ve drove GM’s for years but currently I don’t own one. AFM is not the primary reason but I didn’t like it at all. Had a 2009 G8 w/ 6.0 LB7 and I disabled the AFM shortly after buying it. MPG actually went up on that car. 22 mpg @ 80 mph.

Also had a 2013 GMC 1500 w/ 5.3 and AFM. This motor was gutless and it was terrible on fuel. I also disabled the AFM but it made no difference in MPG.

AFM is voodoo engineering. It’s not worth a crap.

 

[Brains]

LB7 is a 6.6L diesel, pretty sure your G8 was either an L76 (6.0L, GT) or an LS3 (6.2L, GXP).

FWIW, I had a 2009.5 G8 GT myself, in Stryker Blue. Great car, kinda wish I would have kept it and made it faster. Bought it new for a song, drove it for two years and got more on trade-in than I originally paid. Once in a lifetime deal.

 

[vmax]

I’d put a crate in it.
Why the 5-year timeframe?
It should run well beyond that.


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He did put a crate motor in it.

 

[oldag]

LB7 is a 6.6L diesel, pretty sure your G8 was either an L76 (6.0L, GT) or an LS3 (6.2L, GXP).

FWIW, I had a 2009.5 G8 GT myself, in Stryker Blue. Great car, kinda wish I would have kept it and made it faster. Bought it new for a song, drove it for two years and got more on trade-in than I originally paid. Once in a lifetime deal.

The G8 was an incredible car. Four door performance car. Incredible handling.

 

[sidebite252]

LB7 is a 6.6L diesel, pretty sure your G8 was either an L76 (6.0L, GT) or an LS3 (6.2L, GXP).

You’re so right. I also owned a 2002 Duramax at that time as well. I’m having a senior moment I guess? Yes L76. I actually think I enjoyed my G8 as much as any car I’ve driven. Don’t let the 4 doors fool ya!

But I hated the AFM and there were many G8’s that suffered lifter failure due to it.