Help with stock 5.3 swap in 1978 Scout II Lean codes Bank 1 and 2.

[LaidbackLuis]

Finished up a 5.3 swap in a 78 scout. I have a total of about 150 miles on her but cannot pinpoint the issue. Bought HP tuners 2 days ago to record data. So I'm very new to this.

Stock 2005 5.3 vortec
4L60e automatic
NP241C Transfer case with VSS
Headers
Exhaust (2 to 1 collector/ single all the way back)

Minor Symptoms:
Occasionally stalls out in Reverse.
Occasionally stalls out at a stop light

Major Symptoms:
Backfires and sputters under medium to heavy acceleration on highway.

PCM and Harness: PSi Conversion . Only thing they asked was rear end ratio and tire size

Here's a 30 minute drive I logged today. Stalled out in Reverse beginning at minute 1...

It gets really ugly at the 13.30 minute mark. I was at a stop about to enter the freeway.

[5FDP]

More information please. Post the tune file as well.

Exact setup, like mods, exhaust, intake etc etc.

If this is modded in any way you will have to tune for that.

If everything stock you may have some vacuum leaks or exhaust leaks prior to the o2 sensors.

Just going by the logs it seems you may have a vacuum leak or exhaust leak anyway with how the fuel trims react. Also it seems you may some of other weird stuff going on, maybe a possible CAT test that happens when the rear o2 senor are removed from the harness.

Also make sure fuel pressure is a solid 58psi.


Random stuff here. Add commanded AFR and knock retard to your logs. You'll also need a wideband o2 sensor so you can monitor real time AFR while you tune.

[LaidbackLuis]

More information please. Post the tune file as well.

Exact setup, like mods, exhaust, intake etc etc.

If this is modded in any way you will have to tune for that.

If everything stock you may have some vacuum leaks or exhaust leaks prior to the o2 sensors.

Just going by the logs it seems you may have a vacuum leak or exhaust leak anyway with how the fuel trims react. Also it seems you may some of other weird stuff going on, maybe a possible CAT test that happens when the rear o2 senor are removed from the harness.

Also make sure fuel pressure is a solid 58psi.


Random stuff here. Add commanded AFR and knock retard to your logs. You'll also need a wideband o2 sensor so you can monitor real time AFR while you tune.

Thank you for the quick reply. I will add the tune provided by PSI as well as add AFR and knock retard.

[2xLS1]

#1 problem I see on swaps is fuel pressure.