Truck won't idle, dies on decel

[Tiggerwelder]

Hey guys, trying to get my truck tuned after swapping out the tired 5.3 for a fresh 6.0 with a BTR Stage 2 cam, long tube headers, and an intake tube. The fan has been replaced with an Caprice police special dual fans. I tried putting a 6.0 VE table in and it got worse. I have a new AEM 4110 O2 sensor, and it shows AFR's that vary a good bit. I cant get it to log on the graphs, but the gauge reads 14.7-15 and the table part of the scanner reads 10.2 but occasionally jumps to 14 or 19. I have verified that I have no misfires, good compression readings on all 8. I don't have enough powder to blow it up, and I really do need my truck. Here is a log, it looks crazy. Any ideas would be greatly appreciated!

[5FDP]

Post the tune.

Did you change the rest of the stuff that would be wanted for a starting point using a 6.0?

Like all idle airflow tables, base running airflow, start up airflow, idle timing and things like that.

Any change in injectors? Stock 25/lb/hr injectors for sure won't be enough, hopefully it's a flex fuel truck with 33's.


The wideband in the log may need some different settings, it shouldn't bounce around like that at all. Whatever the gauge is reading is what the channel in the scanner should show. Once that is sorted you can create a AFR error with the wideband to fix the airflow model and correct the rest of the fueling and likely mainly of the drive ability issues.

[Tiggerwelder]

The truck is flex fuel, standard flex fuel injectors. I have a NNBS intake and throttle body and an xlink that I haven't put in yet. I change the VE table and the engine size, cylinder volume etc. This is my first dig into the LS swamp. Thank you for pointing me in the correct direction.

Mike

[Tiggerwelder]

Here is one of the tune files. I say it that way because nothing has really worked.

[Tiggerwelder]

regarding the AEM 30-4110, I have added a wire from terminal 5 on the MPVI to the battery negative terminal with no improvement. I rescaled the output to the graphs to be 0-20, but it still doesn't show a trace. I feel like I have spent more time dealing with wide band issues than actually trying to deal with the trucks issues. I started with an Innovate LM-1 that turned out to have a bad sensor and was going to be more trouble than it was worth to datalog. I would love to get it to settle down and play nice! Just don't know what to do.

Mike

[Oleblu]

I fought my aem 30-4110 for over a year with the ground running through the engine bay. one day just before I gave up hope I changed my ground to under the dash and away from most other wires. Using only the supplied ground lead without an extension spliced into the harness. After that it was rock solid readout. It still reads really fast but i got rid of all the erratic interference.

[Tiggerwelder]

That is easy enough to try, thanks for the idea!

[gagliano7]

Your raf Base running airflow looks low to me. I have a 5.3 heads and cam and my #'s are higher. Run the Russ K idle config to get your #'s correct. TIming seems low at idle for a cam. What are the cam specs?

[Tiggerwelder]

0.552 lift on both, 212 218 at 0.050" 254 269 at 0.006" 113 Lobe Seperation

[gagliano7]

I had a very similar cam in my 5.3 loved that cam. I would start with 22 degrees timing at idle for that cam as a starting point.

[Tiggerwelder]

I uploaded several of the suggested fixes, still working on the rest. Drove around the neighborhood. It still dies, but not as often and not as quicly! Thanks for the directions and suggestions. I'm not there yet, but I am not done with the ideas.