03sierraslt

iTrader: (22)

That cam should idle perfectly smooth in a 6.0 I've tuned cams bigger then that that had a smooth idle. That's a baby cam for a 6.0, a good can but small.

CanadaLY6

Thanks for the input!
Could it be a tune issue or should I look at the normal curplruts like injectors and coils? They tuned it and I'm guessing they ramped up the amount of misfires the computer will ignore before it throws a code.

I know now after I called them on it that they used the junkyard injectors and not the ones that were on my old engine... I'm guessing the same is true about the coils.

03sierraslt

iTrader: (22)

Either could be the culprit. Did they put the right injectors back in? Is the tune set for the injectors that are in it? GM has used allot of injectors over the years. If the tune is not set for the proper installed injector then that could be the issue, what diagnostic tools do you have available? If its a coil then it will be a specific cyl. not all of them.

Rest assured, with a proper setup engine and tune that motor will idle smooth and run very nice.

CanadaLY6

I don't have much avalaible to me for diagnostics. But I have a buddy with a GM tech tool that I can go to today. I just need to tell him what to look for because he isn't awesome at diagnosing.
The shop I took it to said it will miss on #5 a lot then smooth and miss on all cylinders really lightly (which they said is normal?).
It has the 6.0 injectors that were in the junkyard LY6 and not the E85 injectors that were in my old motor. They tuned if with the 6.0 injectors in it.

I've had the injectors flushed(on the car). I did a compression test and it had 150psi across the board. So I guess it's not a bum motor or cam timing being off.
Ill try moving around coils and see if the miss follows it. If its could are aftermarket could worth it or should I stick with OEM?

Vortec350ss

iTrader: (20)

Stick with OEM.

You had it tuned witht he 6.0 injectors in it, but did they update the injector data properly? Was this a shop that knows what they are doing as far as tuning is concerned?

CanadaLY6

They charged me $700 to tune the engine and tranny so I sure hope they know what they are doing.

It was tuned to the 6.0 injectors but I don't know what they did on the ECU end.
They were telling me that my 6.0 and my 5.3 E85 injectors were the same, which makes me a bit nervous because I thought the E85 injectors were bigger.

They are supposed to be the shop for LS builds in my area. There was an ALMS C6R they were taking off the dyno before they did mine so I would assume they know what thy are doing.
I'm supposed to get my hands on a GM scanner shortly and ill try moving the coils around and see if the miss follows the coil.

Richardman1992

iTrader: (5)

I've got the comp 212/218 low lift on a 114 lsa, had it in my 5.3 for about 15k miles and no issues at all. I think that shop might have messed up your build

CanadaLY6

My schedule didn't line up to get the truck scanned so I will have to wait till Monday now (it breaks me every day I have to drive the truck).

If you don't mind me asking what were your Dyno numbers?

I was thinking that with the larger displacement and the L92 heads and intake mine should have made significantly more power than a 5.3 with the same mods. A stock Ls2 with cam and longtubes with the same tranny and longtubes in a Camaro - on the exact same dyno and tuner made 390+hp.

Edit* I decided to throw a Hail Mary and put a new coil on #5, the cylinder with the high number of misfires. No dice it seems to drive just as poorly.
When I was at the parts store I realized they have used coils off my old 5.3, which are actually different than the 6.0 ly6 coils. Could the issue be that its got 5.3 coils instead of the 6.0 coils? (I didn't even realize they were different)
If its any help it runs its worst when I exit off the highway and am waiting for the traffic light.

01WS6/tamu

iTrader: (36)

Wouldn't be the first time I've seen cats that are partially melted and restrict the exhaust flow as engine run time accrues. Especially if the old motor loaded them up with oil and contaminated them. The restricted cats can and will cause misfires as the engine cannot exhale properly. As the cats get hotter and hotter the brick flows less and less and can vary from a random miss to a whole side dead based off how bad it's stopped up.

As far as the vibration in the cab it could be a bad motor mount. OEM mounts on NNBS trucks suck. It seems every time we have had a motor out the mounts are separated.

5.3/6.0 coils are interchangeable.
The best thing you can do is put all the stock parts from your truck back on coils injectors etc cause the damm truck ran fine before and then tune the 6.0 accordingly to correct it's manners.

If you can get the truck straightened out swap the torque converter and it will wake it up a bunch. My 07 cammed vmax 6.0 felt doggy regardless of the numbers until I swapped the converter and it majorly woke it up.

CanadaLY6

Thanks for the input!
I did think about the cats but it ran super smooth with the exact same cats so I dismissed them.
Would the difference in exhaust output between a stock 5.3 and a (very lightly) cammed 6.0 be that much?
The 5.3 even though it had 308,000km on it ran glass smooth to the point where most people couldn't tell it was running at idke without looking at the tach.
Ill have them look at the cats.

I thought about the motor mounts, but once again unless they weren't bolted up right would they deteriorate that much since the truck was droppe.

I called them out on not swapping my injectors over even though they said they did, I'm assuming they didn't do the coils like they said they did.

To top it off the "ground strap" they put on it is the messiest hack fix I've ever seen!

It's going back tommorow because its actually starting to run so rough at idle it has stalled out on me twice now, once while I was going left at an intersection. The truck starts right back up, but hardly what I paid for especially since I paid for a top quality vette shop to do the work.
I told them to keep it for a few days and not to give it back to me till its right. Ill let you guys know what they find.