2015 vlom issue???

[klzemx3]

Sorry for what i am sure is a topic of lots of discussion, but i have one that I can not work out. L83, lost a lifter, non dod lifter. I decided to go back with the dod system since orginals didnt fail until 236,000 miles. also decided to do full engine clean up and build. Bored 20 over, new pistons, main bearings, rod bearings and rings. heads fuly checked as well, all gaskets replaced. all re installed, have a miss fire on 1 and 7. compression is 190 on both cranking, 35ish running. both intake and exhaust lifters shut down as soon as oil pressure builds. put a new vlom on during rebuild, and replaced it again just to be sure, same resuts. ANything i could be missing here. also air pressure checked the vlom- not leaking past the solenoids. any help? anyone been through this?

 

[klzemx3]

I should also add that the cylinders also will not re activate with the vlom unplugged. I dont beleive the vlom is the problem/ but it does seem to be oil pressure related. oil pressure sits right on 40 psi at cold idle/ but as soon as it logs p0300 code, it does jump the pressure up to 55ish. reset codes and drops back to 40. I havent ran it much longer due to finding the lifters shutting down. during the rebuild, i used delco lifters, but thought they were giving me issues so changes then out to melling which appear to be a far better built lifter. new melling oil pump, oe head gaskets, Mahle head bolts. new timing chain and cam bolt. timing marks are dead on lined up. Oe camshaft. new oil barbell installed with rebuild. I am at the point of puling engine back out and going over everything one more time, but im already out the cost of machine work, 2 sets of lifters, 2 sets of head gaskets and head bolts... just hoping someone has seen this before and has a suggestion. thanks,

 

[Miami-Dade]

@klzemx3 Moved you here from 2021+section.

Welcome from Miami&Queens NY!

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please. If we can't see it, it does not exist.

I cannot personally assist you with your issue, but other members of this Forum much more knowledgeable than me in troubleshooting this area will chime in.

 

[pronstar]

No offense, but I’m trying to wrap my head around doing all that work to the motor, but retaining AFM/DOD…

 

[klzemx3]

No offense, but I’m trying to wrap my head around doing all that work to the motor, but retaining AFM/DOD…

My failed lifter was on a non dod cylinder. Number 5. It has 236000 miles on it, so I didn’t see it being a big problem, and I do enjoy the 22 MPG and didn’t want to lose that. To each their own opinion, but I would say the system worked well for as long as could be expected. I feel like the problem I am having now is somehow building excess oil pressure that gets to lifters and shutting them down outside of the DOD. Just not sure how that is possible.

 

[klzemx3]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please. If we can't see it, it does not exist.

I cannot personally assist you with your issue, but other members of this Forum much more knowledgeable than me in troubleshooting this area will chime in.

 

[West 1]

I am late seeing your issue. It is over a month now, any progress?

Your compression numbers show the new pistons and rings are working well.
Problem is in the valvetrain.

I have used OEM AC Delco and Melling Lifters in these LS engines. I used to use Sealed Power but I heard they are now using off shore lifters that I do not trust. Top Line in Michigan makes the roller lifters and I would use them, they also are sold under the name Johnson Hylift. I think those are in the Melling box. At least they were.

The AFM system like oil pressure to be at least 26lbs and less than 65 lbs to work properly. There is a by pass in the oil pan to avoid the high pressure. Did you keep that at the rebuild?

2 VLOM manifolds with same problem rules that out I would think?
Lifters locking in the open position is odd, normally only see that at very high miles?
Any chance push rods are the wrong length?

Curious what you finally found.