LC9 DOD lifter issue
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Teching In
Joined: Sep 2020
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LC9 DOD lifter issue I've been searching and haven't found any posts with my same circumstances. Hoping someone will point me in the right direction. 2012 LC9 with 197k miles. Not the cleanest engine inside. DOD lifters were making some horrible noises from #4. Replaced them as well as the VLOM while I was at it because of how nasty the old one was. Oil pressure sending unit is new as well. Still have misfire on cyl. 4 so I pulled the valve cover & found that when I start it, the rockers move normally. As soon as the oil system pressurizes( I presume that's what it is because it's about 2-3 seconds after start up) both rockers stop moving. So I'm assuming that the DOD lifters are getting oil pressure and locking shut. That's the only cylinder doing it though. 0 compression in that hole too. So I disabled the DOD system in HP Tuners and tried it again. Same exact result. I'm unsure where to go from here. Anybody else run into this scenario before? I'm tempted to just swap cams and do the DOD delete if I can't get this resolved. But I feel like there is a simple answer that I'm missing.
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Joined: Aug 2024
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I've been searching and haven't found any posts with my same circumstances. Hoping someone will point me in the right direction. 2012 LC9 with 197k miles. Not the cleanest engine inside. DOD lifters were making some horrible noises from #4. Replaced them as well as the VLOM while I was at it because of how nasty the old one was. Oil pressure sending unit is new as well. Still have misfire on cyl. 4 so I pulled the valve cover & found that when I start it, the rockers move normally. As soon as the oil system pressurizes( I presume that's what it is because it's about 2-3 seconds after start up) both rockers stop moving. So I'm assuming that the DOD lifters are getting oil pressure and locking shut. That's the only cylinder doing it though. 0 compression in that hole too. So I disabled the DOD system in HP Tuners and tried it again. Same exact result. I'm unsure where to go from here. Anybody else run into this scenario before? I'm tempted to just swap cams and do the DOD delete if I can't get this resolved. But I feel like there is a simple answer that I'm missing.
Thread Starter
Teching In
Joined: Sep 2020
Posts: 2
Likes: 0
No kidding? I never did figure it out. Decided to just do a DOD delete. Went old school and used an LQ4 camshaft which interestingly is slightly smaller than the LC9 cam specs. Did a custom tune and that suburban now gets 18mpg on the highway at 80 mph and a full load of passengers and a roof rack. Less to go wrong now.
I spoke with people that know LS engines better than I and every one was scratching their heads. I'm sorry I don't have more to offer you. Maybe time to consider a DOD delete???
I spoke with people that know LS engines better than I and every one was scratching their heads. I'm sorry I don't have more to offer you. Maybe time to consider a DOD delete???
