DOD delete questions. I did a search.

[inspector12]

I have a 2007.5 chevy silverado with a 5.3. Replaced lifters, valley cover with non DOD stuff. Still stock cam though. Runs fine. But when in gear at a stop light it will miss fire on just he DOD cylinders. 1,4,6,7 About to replace the brake switch which is bad, but having serious dought that is what is causing the problem. I deleted the Codes and also disabled the COT as well as the DOD. So far it still does it. Pull up to a stop light and sit there for a second and it will start misfiring. Cleaned the injectors just for extra mesure. Any ideas will be greatly appreciated. Thanks in advance.

[inspector12]

So no body has any clues?

[IDRIVEAG8GT]

You missed some code or master enable/disable.

[Chris@HPTuners]

the stock cam has a different profile for the dod cylinders.

[inspector12]

And the cam profile causes them to only miss when in gear at idle? Just asking cause that sounds fishy to me as I never known them to go into four cylinder mode while at a stop light. Some of the searches said something about the latest Beta, not sure if mine is the absolute latest, but haven't had any other issues with any of my other vehicles. So you think the cam profiles are keeping the valves open at idle or what?

[SA_perf]

I had the same problem wasn't really a miss feel more of a out or balance engine. The dod cylinders had 50 psi compression less than the non dod cylinders. I put a 04 5.3 cam in it and the compression equaled out and ran fine.

[inspector12]

You missed some code or master enable/disable.

Id be the first to agree with you, but I've had too many other ppl look at it to make me think that's it. I'd love for it to be! That's an easy fix then lol. I disabled the DOD and the COT then 10,11 and all the DOD codes as well 3400-xxxxx I don't have in front of me currently as I'm at work. Thanks for you input. If you have a list of stuff to disable like the ones I listed I would double check for sure. Thanks again.

[inspector12]

I had the same problem wasn't really a miss feel more of a out or balance engine. The dod cylinders had 50 psi compression than the non dod cylinders. I put a 04 5.3 cam in it and the compression equaled out and ran fine.

Ok that's what I was wondering if that's what Chris was talking about. I'll do a compression test to confirm and if it's like yours I'll do that same thing. Thanks.

[Chris@HPTuners]

yes, this problem has caught out some of the best engine builders i know. Above about 2500rpm the engine seems to run fine, but is down on power and at idle it misses on the 4 dod cylinders.

Cam doctor shows the profile different for those 4 cyls.

Usually when people do the mod they put a different cam in and so never see the issue.

Chris...

[IDRIVEAG8GT]

A little research shows that the only thing different is the lift on those particular lobes. They may have a different base circle on the cam lobe for DOD cylinders to take up the slack in those goofy ass lifters, and therefore require a different length pushrod to get the valves to shut completely st lower RPM. Another words you have way too much preload on the DOD lobes, and could possibly damage that set of LS7's due to plunger compression.

Measure it with a PR length checker, get a set of correct length pushrods for those cylinders and have at it. Or, change the cam.

[SA_perf]

I found preload to be the same on all cylinders. I have talked to several people on this subject and have yet to find anyone that can answer it. I can not get anyone like flow tech or several others to explain this to me. You can find my threads all over ls1 tech,performance trucks,ls2 tech. The dod cyl have a 1.3mm higher lift. Some say the higher lift is for the extra weight of the lifter. HSV is pretty smart on ls2 forum about dod and has illistrations of oil flow.

[camaro1]

i have turned off the dod on many silverado's and never had any issuse with the stock cam, no parts changed just turned off in the tune. cant see the lifters causing that issue as long as your valve lash is correct for all the cylinders

have seen people remove the vvt with the stock cam and have low power issues. was the op's truck a dod and vvt engine?

[DSteck]

i have turned off the dod on many silverado's and never had any issuse with the stock cam, no parts changed just turned off in the tune.

Totally different.

[camaro1]

also had a guy with a saab 5.3(like trailblazer) removed all the dod and kept the stock cam and no issues just turning off the dod,,,

good to know about this issue,

maybe different year dod cams are set up different,, dont know how the guy with the saab got away with it. he had the whole project done then called because it was in 4cyl mode all the time, we turned off the dod and codes and it drove fine, been over a year now

[inspector12]

This truck only had DOD, and I'm. Going to check the lift on the DOD cylinders against the non DOD ones for curiosity. I appreciate everyone's input a lot thanks guys.

[SA_perf]

It is going to be very difficult to see the 1.3 mm difference. I would like to know what you come up with on your compression test? I believe you are working on a Lc9 engine same as I was.

[Destroyer357]

Has this been solved yet? I just deleted the AFM/DOD Mechnically on a 2008 Tahoe and purchased HP Tuner 6011 getting ready to tune it out. Hopefully I wont run into the same problem...

[Warpbender]

Had a performance shop swap out my DoD lifters with LS7 on my '12 Z71 Silverado with the same result. DoD cyls. Misfired at idle and torque was deficient. After weeks of research they changed the cam to a performance cam. Runs much better but I need a proper tune. Wish I had seen this thread much earlier.

[castorjames]

Just happened to me, 2008 5.3L, deleted all the DOD hardware except cam, low compression on dod cylinders, used smaller pushrods and the compression was ok, but still noticiable wough idle, and if i left there idling it will start to make ticking noise,, just replaced the cam with a 2004 stock 5.3L and is perfect now.. soo anyone else deleting DOD should replace cam too..

[Jae240]

Isnt that part of doing a dod delete is a cam swap?