Need help troubleshooting fresh swap

[Jerm83]

Hello everyone , I have been lurking here for a while but this is one of my first posts. I recently swapped a 2005 LQ9 6.0 into my 69 GMC and I recently got it running but it's having issues. I purchased hp tuners pro and I have eliminated the vats and the rear o2 sensors. The engine runs fine when fire started but it will slowly start running worse. If I try to drive it it acts like it's in low power mode but I am not getting a dtc indicating it is. The only thing that strikes me as odd is I do not see any response from the o2 sensors. One came with the swap and the other is new but neither seem to be reading any voltage on the hptuner software. However if I disconnect one of the sensors I get a code for a o2 sensor unplugged. My thought is I should be seeing something from the o2 and since I am not it leads me to believe this is the cause of it running bad. I haven't been able to add a wideband o2 to the system yet to check the a/f ratio. I am still learning all of this software and this is my first ls swap. Any advice would be appreciated.

[BR3W CITY]

unplug the maf, does it run better.

[Jerm83]

I unplugged the maf and is does run better than it was but could still be better. I have been reading more and it sounds like I need to do some adjustments to the maf tables.

[72blu]

I had a problem with my swap were the engine seemed to be in limp mode yet no codes were being thrown. Ended up being that the O2 sensor plugs were switched and the left plug was in the right sensor and the right plug was in the left sensor. I switched them and it ran fine after.

[Rich84]

Thanks for the information and good luck..

[Jerm83]

Originally Posted by 72blu

I had a problem with my swap were the engine seemed to be in limp mode yet no codes were being thrown. Ended up being that the O2 sensor plugs were switched and the left plug was in the right sensor and the right plug was in the left sensor. I switched them and it ran fine after.

I honestly may have done the same thing. I will need to double check that tonight, thank you! I guess i will pull one and see what bank it shows disconnected in the codes.

I also will be getting a replacement power cable for my AEM wideband gauge today so that should help figure out what exactly is causing the issues. I appreciate the input everyone!

[BR3W CITY]

Originally Posted by Jerm83

I unplugged the maf and is does run better than it was but could still be better. I have been reading more and it sounds like I need to do some adjustments to the maf tables.

If you modified any of that stuff, then revert to an older version (and if you haven't been saving incremental versions....well, now you probably will )

Modded MAF tables, VE, PE or any of that stuff will make some of this impossible to diagnose, as we can't bear witness to any of what occurred. If you don't have a stock flash availalbe, check the HPT repository.

[Jerm83]

Originally Posted by BR3W CITY

If you modified any of that stuff, then revert to an older version (and if you haven't been saving incremental versions....well, now you probably will )

Modded MAF tables, VE, PE or any of that stuff will make some of this impossible to diagnose, as we can't bear witness to any of what occurred. If you don't have a stock flash availalbe, check the HPT repository.

I was smart enough to save a stock tune and created a second version for modifications. However i can see how saving several versions will be handy. So far I have only deleted the rear o2 sensors so I should be good to go, but if i do have any issues i can revert back to the stock tune i saved and can start over. I will be swapping the o2 connectors when i get home. I found a picture i saved when i unplugged the driver side o2 and i got a P0059 (bank 2 sensor 1) code. From my research bank 2 should be on the passenger side. I really appreciate the help and I will let you know how tonight goes.

[Jerm83]

Originally Posted by 72blu

I had a problem with my swap were the engine seemed to be in limp mode yet no codes were being thrown. Ended up being that the O2 sensor plugs were switched and the left plug was in the right sensor and the right plug was in the left sensor. I switched them and it ran fine after.

That was the issue! Thank you 72blu and thank you too BR3W CITY for the assistance, I appreciate the help.

[72blu]

Originally Posted by Jerm83

That was the issue! Thank you 72blu and thank you too BR3W CITY for the assistance, I appreciate the help.

Haha glad im not the only one who made such a simple mistake
Im happy to be of assistance!!

[BR3W CITY]

another solve for the forum. We gotta have a pretty high clearance rate