Chevy and GMC Duramax Diesel Forum - Reply to Topic
11-16 LML Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission, Etc.

Thread: Help smoking after down grade Reply to Thread
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  Topic Review (Newest First)
09-11-2019 11:13 AM
Jessapio I contacted PPEI and they said the same thing. I think it was unplugged but the shop that I bought the truck from probably seen it unplugged and figured it should be plugged in. Hopefully I’ll run up to the cabin this weekend and see. I thought this truck was amazing before now it running noticeable better and just blows my mind how much power it has! Thanks again for all the info.
09-11-2019 09:42 AM
D_R_C ^^^^
There’s 2 positives when going with a aftermarket downpipe.
You’ll have something to do for about one day removing the stock DP installing the aftermarket downpioe.
Your wallet will be much lighter not having to lug around that extra weight money you spent on the DP.
Only if your having exhaust leaks from your stock downpipe, leave it on.

Yes, leaving the egr plugged in with even tuners saying it’s ok could lead to issues.
I had the same problems, luckily my original Edge Insight I monitored EGR command.
I noticed it was jumping up and down from 0% - 100% running rough, I unplugged it, this solved the problem.

Below is for the LMM, stock is oval shaped about 2 3/4” x 3 1/4” where the aftermarket is 3”, I had absolutely no gains.
09-11-2019 05:44 AM
eli_harper13 My truck has almost 180,000mi and been deleted since 100,000mi. I still run the factory down pipe with no issues. All changing out the down pipe does is change the sound of the exhaust and remove the port for the 9th injector. You will be fine to leave the factory down pipe if you wish too. And the issues you were having, I would say, was definitely from the EGR still being plugged in. I followed the old H&S instructions when deleting my truck and it clearly says to unplug it. When deleting my dads truck with PPEI, I asked them and they said to follow the H&S instructions too.
09-10-2019 04:33 PM
SilverGorillaLML You can run stock down pipe without issues I've got a few running around like that and theres plants of others I'm sure. Your egr still being plugged in could have affected things.
09-10-2019 04:32 PM
Jessapio Thanks for everyone’s thoughts and input I just joined this forum and have had a lot people trying to help...I think I’ll stick around and hopefully be able to help someone in the future!
09-10-2019 04:29 PM
Jessapio The truck has a full exhaust and the delete is done through the PPEI tune it has stock down pipe still. I’m thinking I need to replace the down pipe soon so it don’t blow up on me.
09-10-2019 04:25 PM
Jessapio At the shop they noticed the egr was still plugged in so they disconnected it. Now my truck is coming up on boost a lot faster and really feels smoother. I don’t know if the tune was causing the egr to stay open or what. Once I get the scanner I’ll know more but for now I’m happy.
09-10-2019 12:30 PM
SilverGorillaLML Personally I've never seen or heard of an lml blowing the egr open under load since they've been deleted n tuned in 2013 but theres a first for everything.
09-10-2019 11:09 AM
Jessapio Ok so took it to shop and this is where I’m at. my truck has the egr turned off from the ppie tuner. There is no block off plate. What they think is the egr is opening while I’m costing down a long hill and causing the Engine to run rich. I’m getting a scanner so I can check the mass air flow sensor while I’m doing the same down hill run. They say if the numbers are low that’s probably what’s going on. They we’re not able to open the EGR because of the tune that’s on the truck so they could not replicate the problem . I should have the scanner by end of the week so I’ll update ASAP. Thanks
09-10-2019 06:52 AM
Originally Posted by Jessapio View Post
Well after a few hrs the hose was soft no pressure so idk what’s going on
GOOD News, not head gaskets!

Is your coolant level dropping or staying the same, check it several mornings in a row when it is cold to see what it is doing. If necessary use a marker to mark the level the first time.

If it is dropping you are losing coolant somewhere and the white smoke tends to indicate it is going into the cylinders. A coolant leak in the EGR Cooler (IF it is still there) or the Turbo both can put coolant into the engine.
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