2009 5.3 AFM bad lifter - what cam for the DOD delete?
A failed AFM lifter is the usual trigger for a full AFM (DOD) delete: Failing AFM lifter: single-cylinder misfire, persistent tick, rough idle, low power, cylinder-specific misfire code; can progress to bent pushrods, cam lobe wear and metal in the oil.
Replacing just the bad lifter isn't a delete. A proper AFM delete: non-AFM camshaft, all 16 conventional roller lifters (not just the 8 AFM lifters), new lifter trays, and blocking the deactivation oil circuit (non-AFM valley cover or plugs); heads must come off, so head gaskets, head bolts and exhaust gaskets too. Plugging the oil passages while keeping AFM lifters is not a delete: the collapsible mechanism remains and oil can back-feed into the DOD channels and collapse lifters later.
Cams built for the delete (from our catalog — the maker describes each as an AFM/DOD delete or conversion cam):
The "DOD conversion" cams keep stock-like valve events, so they're the choice if you just want the engine back to normal. Performance truck cams add power but may need springs, a converter and more tuning — check each cam's page in the cam finder.
Don't forget: AFM engines use a single-bolt cam; a three-bolt performance cam needs a matching three-bolt gear and chain. Gen IV moved the cam sensor to the front cover. PCM must be recalibrated to stop commanding deactivation; aftermarket cams also need idle, fuel, spark and torque-model changes. Add GM oil-pan pressure-relief-valve cap (12639759) when deleting AFM to stop oil spray/consumption; replace the pickup O-ring.
Confidence: medium — sources disagree or are limited; check the sources below.
Community discussion
- www.gm-trucks.com/forums/topic/242447-2009-53-afm-bad-lifter/
- www.performancetrucks.net/forums/internal-engine-modifications-158/09-
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- Ask Away! How to Delete the AFM System in a 5.3L LS Truck Engine (Jeff Smith) — OnAllCylinders (Summit Racing)
- DOD, AFM, And DFM Deletes: A Q&A With Michigan Motorsports — LSX Magazine