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Replaced engine 5.3L due to AFM. Turn off AFM now?


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Hi everyone- brand new to the forum. Thought I'd throw out a question about my 2008 Chevy Suburban LTZ sitting in the shop right now waiting on a replacement GM-cert refurb engine. Should be put in in the next several days.

 

Truck has 165K miles. Started chewing oil back in 2012 at around 80K. Was in shop 3 times in 2013 with the usual AFM issues up until the 110K mile mark when the 3rd operation was done (I think it was replacement of all pistons). All-told, about $7250 of warranty work done to truck related to AFM. Soooooo, truck recently had misfiring on cylinder 5, low oil pressure warning, drop of pressure, left on side of road. Towed to dealership. Engine not holding pressure, needs new engine.

 

I expect the engine to have 3 yrs/100K warranty.

 

My question is this: Should I disable the AFM with the "Range AFM Disabler" (http://www.rangetechnology.com/products/range-v8) device on this 'new' engine to (likely) eliminate any potential issues, or should I trust the newer version of this engine that was ordered will behave and perform as desired.

 

I am also a bit confused about posts discussing 'deleting' the AFM with "kits" or having to put different parts into the engine to turn AFM off, while getting normal, expected behavior from the engine.

 

Thank you all for any feedback. Love this forum!

 

John

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2 engine failures due to AFM?? Wow, that sucks... sorry man. I think you already know the answer as to what you should do. I would definitely disable it. I wouldn't trust the new engine to behave any differently that the old if it still has the AFM. I just put the Range AFM delete on my 2016 last week. My truck runs so much better now. Love it!! Doubt I'll ever go back to using the AFM ever again. You could use a tuner to disable it, but it may void your warranty on your motor, that's why I went with the range module instead. Changing parts in the motor is another way to delete it, I believe you would have to change the lifters, pushrods, and Cam at the very least, there may be more that would need replaced as well. Someone else that knows more about that may be able to chime in and answer that.

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Know what is funny...the misfiring was on a non AFM cylinder...1, 4, 6, and 7 are the AFM yet misfire was cylinder 5. Usually 7 is king for misfires.

 

If you are dropping an engine in and keeping the truck, get the Range and shut the AFM off. ASAP.

Edited by 15HDriver
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  • 3 weeks later...

Hello new to forum and I am experiencing low compression on cyl 7 on my 2011 Silverado I'm running a leak down test in morning but I keep seeing this AFM talk and idk much about it other than its re active fuel management and the little I have read on here but I did have a loose rocker on that cyl took all rockers and pushrods out all seem fine took intake manifold off to find a lot of gas in cyl 7 intake port ? Hoping for a bad valve as I don't want to replace rings and pistons sooo any suggestions or has anyone experienced this issue

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  • 3 weeks later...
  • 2 weeks later...

Hello new to forum and I am experiencing low compression on cyl 7 on my 2011 Silverado I'm running a leak down test in morning but I keep seeing this AFM talk and idk much about it other than its re active fuel management and the little I have read on here but I did have a loose rocker on that cyl took all rockers and pushrods out all seem fine took intake manifold off to find a lot of gas in cyl 7 intake port ? Hoping for a bad valve as I don't want to replace rings and pistons sooo any suggestions or has anyone experienced this issue

Did you get yours fixed? Sounds like your lifter was compressed.

 

 

Sent from my iPhone using Tapatalk Pro

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  • 10 months later...

Replaced engine at 74000 mi due to major engine tap at start up. Under ext warranty. Rebuilt gm installed. Immediately put range device in. 08 ltz avalanche 5.3. Better trans shift & hopefully no more tick. Feels like a new truck. Lost a mile or 2 but that's OK.lol

Sent from my ALCATEL A564C using Tapatalk

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  • 2 years later...

So I’m pretty much stumped at this point, I got a 2009 Silverado 1500 5.3L I had a flashing CEL at cruising speeds suspected it to be the afm issue so decided to buy an afm delete kit. Put the kit in everything went well motor runs great but still same thing.. truck runs great if I’m getting on it or getting up to speed but as soon as I get into 6th gear cruising check engine light starts flashing and I’ll floor it and get it to up shift and it’ll go away. I had it retuned twice thinking maybe that was the issue, there’s code po3401 which is something to do with 4 cylinder mode but won’t stay off after turning it off in the tune.. 

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23 hours ago, Brandon2013! said:

So I’m pretty much stumped at this point, I got a 2009 Silverado 1500 5.3L I had a flashing CEL at cruising speeds suspected it to be the afm issue so decided to buy an afm delete kit. Put the kit in everything went well motor runs great but still same thing.. truck runs great if I’m getting on it or getting up to speed but as soon as I get into 6th gear cruising check engine light starts flashing and I’ll floor it and get it to up shift and it’ll go away. I had it retuned twice thinking maybe that was the issue, there’s code po3401 which is something to do with 4 cylinder mode but won’t stay off after turning it off in the tune.. 

Did you replace the camshaft?  P3401 is the code for the Cylinder 1 Deactivation Solenoid Control Circuit.  Is the VLOM gone or still there and hooked up?  You need a bi-directional scan tool like a Tech-2 to verify that AFM has indeed been turned off.

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