bad stumble/miss 5.3 turbo

[sarg]

It honestly feels like I am hitting a rev limiter. It is a little fat, but not overly so. But when going into load/boost it stumbles badly and misfires. It sometimes will pull through and clean up, but not sure why it is happening. I just changed out the plug wires to try to eliminate that. Next comes the plugs. Here is the scan and tune. It is a work in progress and my first boost ls motor, so be gentle Let me know if you see anything out of the ordinary.

NEW Mike Sargent Auto 3 bar v2.0 e85.hptDefault Imperial 3 bar 2.cfgcruise and stumble 9.27.13.hpl

[sarg]

More info...
5.3
227/233 cam
hi ram intake
4l80E trans from Jakes
S480 turbo
160 lb injectors (hi-z)
plenty of fuel pump
55 psi base pressure

[lwrs10]

Why does your TPS never show WOT? Did you go WOT in that scan?

[mecanicman]

If your injectors are 160#, why does your ifr table show 90?

[sarg]

I never went wot, as I was trying to roll into it. I never got to the point where I wanted to go WOT as it was breaking up so bad. Injectors are 160 at 43.5 psi, I have it at around 55 psi so they are flowing almost 180 lbs. I have the tune scaled in 1/2 for more resolution up top when it exceeds 1.20.

[sarg]

Plugs apparently were not the issue. They all looked ok.

[sarg]

Wondering if an exhaust leak (I have a small one on the driver's side) may be giving me a falsely lean reading at the wideband. I guess I could try leaning it out a bit.

[sarg]

Well, added a ground, made the old engine ground better. Ran a better wire for the alternator to the battery and changed the plugs. If anything the misfire is no better. And it does not seem to idle as well as it did before. Getting really frustrated. Plugs are at 22.

[sarg]

leaning it out helped a good bit. I am wondering if that tiny exhaust leak is affecting the readings. When it is in the 11:1 range it seems to do ok. Below that and it gets angry.

[hellian540]

Did you ever get this sorted out? I'm having a similar issue with my turbo 4.8 swap. It's acts like a 2 step rev limiter when it comes into boost.

[sarg]

Actually yes, it was a brain fart on my part. The cells above where I was tuning were too fat and the ecu was blending the areas. Total brain fart on my part. In the scanner it would never hit those cells, but they were for sure what was effecting the fueling.

[prostreet1967]

old thread but sure hope this fixes my issue