2007 Avalanche LY5 AFM Delete or L33 swap
Thread Starter
Staging Lane
Joined: Mar 2006
Posts: 63
Likes: 0
From: Peoria, IL
2007 Avalanche LY5 AFM Delete or L33 swap Hi all, thanks in advance for helping my son and I out. I've done a lot of hotrod SBC's but when it comes to LS engines I'm new at all this.
I'm working on an '07 Avalanche (rear wheel drive only) that has a LY5 5.3L with a P0305 (cylinder 5) misfire that I can't seem to lick. The plugs and wires were changed, and swapping injectors and ignition coils didn't move the problem, it's getting spark and the misfire fault goes away over 2000 RPM. Compressed air through the spark plug hole doesn't reveal an obvious valve leak, so I'm stumped at what the problem is.
Anyway, the engine has 170k miles on a solid southern truck and the AFM/DOD delete hardware costs $900+, and there's a used L33 for sale locally with 60k miles which has me tempted.
What would be involved in making an L33 work in his 2007 Avalanche? Clearly bolting it in isn't a big deal, but the knock sensors are in a different spot, the crank tone rings are different and I'm not sure what other roadblocks would keep it from playing nice with the rest of the truck.
I'm working on an '07 Avalanche (rear wheel drive only) that has a LY5 5.3L with a P0305 (cylinder 5) misfire that I can't seem to lick. The plugs and wires were changed, and swapping injectors and ignition coils didn't move the problem, it's getting spark and the misfire fault goes away over 2000 RPM. Compressed air through the spark plug hole doesn't reveal an obvious valve leak, so I'm stumped at what the problem is.
Anyway, the engine has 170k miles on a solid southern truck and the AFM/DOD delete hardware costs $900+, and there's a used L33 for sale locally with 60k miles which has me tempted.
What would be involved in making an L33 work in his 2007 Avalanche? Clearly bolting it in isn't a big deal, but the knock sensors are in a different spot, the crank tone rings are different and I'm not sure what other roadblocks would keep it from playing nice with the rest of the truck.
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Joined: Aug 2010
Posts: 7,320
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From: Ann Arbor, MI
Someone confirm or correct me, but a search on "GM L33 versus LY5" indicates an L33 is a Gen-3 LS engine and therefore likely has a 24X crank reluctor. In contrast the LY5 is a Gen-4 and therefore likely has a 58x reluctor which the ECU needs.
Since there is no way to convert a 24x signal to 58x, the L33 engine will not work with your ECU; it won't even start.
Again, someone more experience needs to confirm or correct me.
Since there is no way to convert a 24x signal to 58x, the L33 engine will not work with your ECU; it won't even start.
Again, someone more experience needs to confirm or correct me.
Thread Starter
Staging Lane
Joined: Mar 2006
Posts: 63
Likes: 0
From: Peoria, IL
Thank you for your feedback guys. I'm not at all impressed with the gen 4 motor (mostly because of the highly defective DOD/AFM) but I have come to understand the reluctor wheel isn't something that's easily swapped. We didn't go after the gen 3 engine and may have gotten the misfire resolved by replacing the intake manifold gasket. This seemed like an unlikely cause but we were out of other things to try, and it isn't tripping the P0305 fault as readily as it was before we changed the gaskets.