Afm V-4 Noises

[papapump51]

OK heading to the dealer tomorrow in the AM due to this strange noise that is now starting...

 

40 to 66 mph in that area cruising it will kick into V4 mode and I can tell because it sounds like some is starting a leaf blower under my truck - I push the pedal down and back to V8 mode and it is gone . So I at least know when the issue is happening ...

 

So anyone else had this issue? I searched the board and saw there is a new flash for the PCM? or did I miss read? or what the hell is going on!!

 

Thanks for the help I need at least some info soon because I am leaving the state moving on Monday so I hope they can fix whatever tomorrow... thanks guys!!

[98 Z71 SLT]

oohhhh boy...we have TONS of threads on AFM

 

Do a search on my screen name, kick back and read away.

 

OK..there are NO PCM reflashes / updates.

 

BUT, check one thing...Go outside, pop the hood, and inspect the engine oil dipstick tube. The tube should NOT be touching the positive battery cable that is positioned nearby. Make sure there is clearance between these items...they will vibrate when in V4 mode.

 

Other than that...you gotta live with it. My old 08 Sierra...when it was colder out this past winter...you actually felt like you were in a blender in V4 mode...but it seems as Spring came, and the temps warmed up, the blender action ceased...

[motoxxx]

Get a tune so you don't have to deal with that V4 mode anymore. I couldn't be happier ever since the V4 mode disappeared, I literally hated it. No more vibrating or hesitation, plus I get better gas mileage without it anyway. Good luck.

[VMax2007]

Get a tune so you don't have to deal with that V4 mode anymore. I couldn't be happier ever since the V4 mode disappeared, I literally hated it. No more vibrating or hesitation, plus I get better gas mileage without it anyway. Good luck.

 

 

I am by no means a fan of AFM in these huge trucks as I think it's pretty much worthless. But how in the hell do think you are getting better mileage by removing it? I do believe you are getting better mileage with your tune, but I seriously doubt it's because you turned off AFM.

[papapump51]

I have searched on all the issues here as usual - but was just asking - it pisses me off and when I told my friend at GMC he said "uh oh" so no idea what that ment... I was thinking of getting a tune and stopping the AFM but money is the big thing right now since me and the Mrs are moving to SC ... Thanks for help.

[RVJ]

When I bought my 08 Sierra it had a horrible noise while in the AFM V4 mode at about 43-48 mph under a very dead pedal light acceleration. It sounded like a helicoptor and I thought I had a very serious problem. The second it went to V8 mode the noise was gone. I spent a couple weeks looking for a vibration before I removed the plastic engine cover and went for a ride. The noise was gone. The engine cover sits in rubber grommets and was vibrating against a wire loom only under the conditions described above. I drilled a couple holes in the cover and I used a couple wire ties to tighten the engine cover down to the alternator on one side and the oil spout on the other and the noise has never came back. This keeps it from vibrating in a harmonic mode when in that V4 mode. I posted a couple threads about it back in april I think, when I was trying to find the noise myself.

[RVJ]

Heres the thread I was talking about.

http://www.gm-trucks.com/forums/index.php?...p;hl=helicopter

[jrrod2004]

grenade

[jrrod2004]

I sympathize with all that have AFM....i would rather pay for VVT than AFM

[VMax2007]

I sympathize with all that have AFM....i would rather pay for VVT than AFM

 

Well, my truck has both, and I would bet the VVT system saves more fuel than te AFM system does, PLUS it adds power too.

[RVJ]

I love my AFM, my lifetime avg. mpg with 15,000 miles is 17.8. For a 4WD pickup, I'll take it anyday.

[papapump51]

thanks RVJ I will check those out in the AM and also see what GMC has to say in the AM - least I will get some good donuts! mmmmm

[RVJ]

Just remove the cover before the drive(lift up and pull out) and see if it goes away. Good luck.

[motoxxx]

I am by no means a fan of AFM in these huge trucks as I think it's pretty much worthless. But how in the hell do think you are getting better mileage by removing it? I do believe you are getting better mileage with your tune, but I seriously doubt it's because you turned off AFM.

 

 

 

You are right, I don't get better gas mileage because the AFM is turned off, my bad. I get better gas mileage because I have the tune. Regardless, if I could just turn off AFM I would, even if my gas milage suffered. I literally hate AFM that bad...I know I have problems. LOL