BuffaloSS

iTrader: (3)

Anyone have a write-up, or have the time to DO a write-up, for the process of checking for a dead lifter?

As many have seen me post before, I have a "rocks in a can" chatter that occurs only when in 4-cyl mode, and only noticeable when driving in the city (where the sound can bounce off the surrounding cars & buildings). It stops IMMEDIATELY when I slow down enough to let the car kick back into 8-cyl mode.

Given that, would it be one of the DoD lifters, or one of the non-DoD lifters? Which cylinders have which?

I have never taken apart my/an engine, and would like to NOT ***k it up in doing so, so a write-up or basic how-to would be most helpful. Thanks!

Bryan921SS

Would that be in a Haynes or Chilton manual??

beznich

I tuned off DoD all together. Sorry I can't be much help to you. There is a good sticky here is the LS4 forum on the entire DoD system, but that's about all I know. Good Luck

06MonteSS

the ECM will shut down cylinders 1, 4, 6, and 7 to put the engine in V4 mode.


https://ls1tech.com/forums/5322427-post3.html

https://ls1tech.com/forums/5322481-post4.html



.

BuffaloSS

iTrader: (3)

Thanks for the info.

With that, anyone know if it would make more sense for the noise to be coming from a DoD lifter, or the others? Having never seen a DoD lifter, I cannot tell if the two-piece design could be the culprit? Rattling around as the cam hits it on every turn when in 4-cyl mode?

Also, if the lifter failed completely, wouldn't that cause some other condition that enabled a CEL?

impala06ss

If the rattle is coming from the valve train, it shouldn't be one of the non-DOD lifters since they run in both 4 and 8 modes. If the rattle does not have a patterned constant sound, then it may be a fuel/air problem, lifters are constant, not sure you specified.

I don't know how to check a lifter still in the engine. Checking one outside the engine can be done by using a drill press with a push rod mounted in it pushing down on the lifter in a container of oil, timing how long it takes to compress the lifter. A dead lifter goes down faster than the rest. I couldn't begin to tell you how one of the DOD lifters could be checked, but I do have a drawing I found on the net somewhat showing the DOD lifters. Don't know where I got it from.

Kazmaniac

If it did they would have drawings and picks from a '95 Monte Carlo.

I stopped buying those long ago, they only have very basic info, and nothing is relevant.

Buff - I thought Badd post some pics during his cam swap. Changing out a lifter is a good days work on these cars. Camshaft you would want the weekend.

Maybe go after rockers when you have it apart.

neilownz

Might as well change the lifters and cam to something decent that doesnt have DoD.

BuffaloSS

iTrader: (3)

I'd love to still have my Diablo, just to be able to tune out the DoD and see how it affects my already terrible mileage on an average week. It didn't seem to be too bad an effect before, but on long hauls, it was noticeable enough to add to the downside of that tuner.

06MonteSS

yeah, and if ya still had it, I could just create you a custom tune to get rid of that 4/8 surge, so you could still use the DOD tune if ya wanted.... but nooooooo....

LS4SPEED

iTrader: (3)

I've got your old Diablo, I'll sell it back to ya! I got it from EmersonHart, used it once for a tune then removed the tune to go to the dealer for warranty work, and never used it after that.

06MonteSS

D'OH!!

hahahaha