Need help diagnosing

[Fatboy]

06 LBZ with 97k on it. I installed EFI live from SS Diesel Tuning and life was good. The only thing that seemed different than most was that I was blowing a lot of smoke at 1/2 throttle and covering the road at 3/4 throttle. Several thousand miles the truck will intermittently lag and puff smoke at cruising speeds (45-55mph). If I try and give more throttle it bogs down and then seems to catch up, blow out a huge puff of smoke and then run fine. The EGR is turned off but no blocker plate. Airdog 165 is at factory setting. Air filter and mass sensor is fresh and clean. Check engine light has never come on or flashed. Any ideas?

 

[LWATSON]

For starters I would install a blocker plate, the egr can still be pushed open under boost. My lbz smoked way less and spooled quicker after I installed the plate. So I would do that first.

 

[Fatboy]

Thanks - I was thinking in that direction. I was on the debate of doing a full delete instead of the blocker plate. However for the $10-15 I can install the blocker plate and find out if the EGR is indeed the problem.

 

[Chevy1925]

Have you talked to steve?

 

[whytry]

I will not tune a Lbz or Lmm without a blocker plate, not worth the hassle if that tells you anything

 

[Fatboy]

I emailed Steve but I haven't heard back yet.

Any true advantages of the delete over the blocker plate as far as performance? Transmission will be built in the near future and twins are on the docket.

 

[JoshH]

I've never had any problems with an LBZ or LMM without a blocker plate. I don't know why so many people seem to have problems with it. My dad's LMM has been running on a 500+ HP tune for the past 100k miles or so without a blocker plate, and I haven't seen any signs of it blowing open. FWIW, boost does not blow it open; boost would only help keep it closed.

 

[Chevy1925]

the new cold pipe you would put on will flow better, but thats about it.

i would think you would see a better gain stripping the y-bridge, intake runners, and cold pipe at the EGR down and cleaning the build up of crap out of the inside. your heads will be coated as well but that would be a lot of work to just clean the intake channels.

 

[Chevy1925]

I've never had any problems with an LBZ or LMM without a blocker plate. I don't know why so many people seem to have problems with it. My dad's LMM has been running on a 500+ HP tune for the past 100k miles or so without a blocker plate, and I haven't seen any signs of it blowing open. FWIW, boost does not blow it open; boost would only help keep it closed.

how much drive pressure does it take to open one josh? just out of curiousity. i was told anything above 25psi but i doubt your dads rig is only pushing 25psi drive pressure at 500hp

 

[SSchmi5519]

Do you have any logs of the cruising smoke? What tune is this on?

 

[Fatboy]

Hey Steve - No logs but I can hook up the computer and try to get it. Problem is that it's intermittent so I guess I will have to log for a while until it happens. When it first happened I was worried that it was the hot tune but then it will repeat with all tunes, even stock. It didn't happen initially so I don't think that it's the tune. I honestly thought that it was the transmission at first not wanting to down shift from 6th to 5th on a pretty good incline but it has happened on flat ground under acceleration at 45 or so.

 

[SSchmi5519]

Hey Steve - No logs but I can hook up the computer and try to get it. Problem is that it's intermittent so I guess I will have to log for a while until it happens. When it first happened I was worried that it was the hot tune but then it will repeat with all tunes, even stock. It didn't happen initially so I don't think that it's the tune. I honestly thought that it was the transmission at first not wanting to down shift from 6th to 5th on a pretty good incline but it has happened on flat ground under acceleration at 45 or so.

Strange it happens on the stock tune setting also, intermittent are annoying to log. Best thing you can do is keep the laptop in the truck and be ready to log it, or set up the handheld to blackbox read and throw a memory card in it.

 

[whytry]

I think I have more egr problems when The turbo brake is working don't ask me why

 

[Chevy1925]

I think I have more egr problems when The turbo brake is working don't ask me why

drive pressure is why

 

[JoshH]

how much drive pressure does it take to open one josh? just out of curiousity. i was told anything above 25psi but i doubt your dads rig is only pushing 25psi drive pressure at 500hp

He is running around 32 psi of boost.

 

[blk smoke lb7]

He is running around 32 psi of boost.

Think he was talking drive presure Josh but i could be wrong.

FWIW i would do the Allseason big air kit its a very nice high flow kit IMO.Expensive but worth it.

 

[Fatboy]

Okay. Update. I was not in stock before. Steve you made me double check and I was actually in economy. Nearly 100 miles in stock and pull about 6k lbs today with zero problems and zero smoke. Laptop is having some issues so I can't log right now. I am leaning more and more towards egr.

 

[Fatboy]

Laptop is up and running. What pids do I need to log? I did have an insufficient EGR flow DTC. Blocker plate is on its way.

 

[Fatboy]

Bump. Need help on which pids to scan.

 

[SSchmi5519]

standard LBZ imperial is fine