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Tuning an LS or Gen V LT
Starting, idling, shifting and making power all come down to the computer, the harness and the tune. LS or LT, pick what you need:
Gen V LT coverage
2014–2019 Gen V on the E92 computer: L83 5.3 and L86 6.2 trucks and SUVs, LT1 Camaro SS and C7 Corvette, LT4 C7 Z06, Camaro ZL1 and CTS-V. 6L80, 8L90 and (Camaro ZL1) 10L90 automatics, plus manuals. We tune them on HP Tuners and review the logs. We have delivered on a 2023 Camaro LT1 (E92).
2019+ new-body trucks (L84, L87, L8T) and the C8 Corvette LT2 use GM's Global B computers. We can tune those once you have bought HP Tuners' ECM/TCM unlock. That is your step before ordering; we do not sell or perform the unlock.
Free turn-on values are LS swap tools only. LT owners: start with the free Tune Report or Full Custom.
Have a log but no tune file, or a Holley datalog? Send it for a free log review.
Turn-on tune: starting numbers for your build
Pick your engine, injectors and cam; get the values to start, idle and drive it, from real tunes. Then the dyno.
Tune Report: we check your LS or LT tune
Already have a tune? Send your LS or Gen V LT tune file and we tell you what to fix first, in plain English, within 1 business day of getting your file.
HP Tuners walkthrough: 58 steps
The order we tune an LS or LT in VCM Editor: which tables, what to log, the targets and when to move on.
How to wire your LS
Pick your engine, computer, throttle and transmission; get the minimum wiring to start it and what it needs to run right.
Don't blow it up: safe limits
Our limits for air/fuel, knock, timing, fuel pressure and temperatures, and the checks to pass before any wide-open run.
Tune checklist for your build
Pick engine, computer, transmission and mods; get a list of what the tune has to change (VATS, injectors, MAF, trans).
Use at your own risk. This is what has worked on our builds and our friends', reviewed by our lead shop tuner (over 20 years of LS and LT tuning experience). Your combination is different: start conservative, log everything, and don't go wide open until you've passed the checks on Don't blow it up. When in doubt, pay a professional tuner.
The short version
- Every EFI swap needs a tune. Every donor PCM needs reprogramming: delete VATS (or the engine will not start), match injector size and MAF scaling, and match transmission settings; emissions monitors and speed limiters from the donor are also present.
- Match the computer to the engine. Crank reluctor is 24x or 58x; the ECU must match. Tell by the crank sensor (behind the starter): early black 24x, later gray 58x. Still choosing one? The LS swap ECU comparison puts the factory PCM, Terminator X, Haltech and MaxxECU side by side.
- Mods change the tune: a cam, injectors, boost, E85 or a different transmission all mean recalibrating. An AFM engine with an aftermarket cam also needs a full AFM delete.
- Carbureted LS? No engine computer to tune, but you still need an LS ignition controller.
Sections
Turn-on tune
Start here: the values to get it running, with ranges from real tunes, then the dyno.
Don't blow it up
Our safe limits and the checks to make before any wide-open pass.
Do I need a tune?
Which swaps and mods need the computer changed.
Swap tune checklist
VATS, injectors, MAF, transmission, reluctor and throttle.
Tuning fundamentals
VE, MAF, fuel trims, wideband and injector data.
Computers & tuning tools
Factory PCM vs Terminator X, and HP Tuners vs EFILive.
HP Tuners, step by step
The order we tune an LS in: tables, what to log, targets and when to move on.
Cam tuning
What a cam changes in the tune, and cam-by-cam needs.
Fuel, E85 & boost
Injectors, fuel system limits, and tuning for boost.
Transmission tuning
Shift timing, line pressure, controllers and converters.
Who tunes it?
Pay a tuner or learn to tune it yourself.
Tuning glossary
The words you will hit: 24x/58x, VATS, AFM, DBW, stall.
Tuning questions, answered
- Why would VATS and starter checks refuse to disable on an E38 ECM even after a Write Entire?
- What is the exact procedure to disable DoD/AFM in the tune without a mechanical delete kit?
- How do I set up 6L80E part-throttle and WOT shift tables after a gear and tire change in an engine swap?
- How do I add a real flex fuel sensor to an E38 Camaro and dial in E85 — what needs adjusting beyond enabling multifuel?
- What is needed to segment-swap a 4L60e E38/T42 truck to a 4L80E?
- Does simply selecting 4L80E under the transmission tab convert a 4L60E tune, or is a segment swap required?
- What is the correct procedure to put the software in speed-density mode for a MAF delete?
- How do you properly fail the MAF for speed-density tuning without breaking transmission shifting?
- What is the right way to force the PCM into speed density on a built 6.0 with larger injectors?
- How do you transfer injector data correctly when swapping to larger injectors at a different fuel pressure?
- How do you set up the scanner to tune with a 2-bar or 3-bar MAP sensor on a custom OS?
- What tune changes are needed after a mechanical AFM/DOD delete on a 2008 Tahoe 5.3?
- How do you use a logged idle-desired-airflow histogram to set base running airflow?
- How do you set up flex fuel so the car adjusts commanded lambda between E85 and pump gas?
- What do I need to buy and set up to tune a twin-turbo 408 LS with EFI Live — do I need a custom OS, and should I run MAF or speed density?
- What is the difference between Trans Abuse Mode and Shift Torque Management, and should abuse mode be disabled?
- What does it take to convert from an 0411 LS1 PCM to an E38 controller, and will the stock dash and gauges work?
- How does the E38 ECU use MAF versus VVE tables for fueling, and how do I trim each one?
- What causes a Gen III LS-swap drive-by-wire system to enter limp mode at wide-open throttle with P1125, P2120, and P2125 despite apparently correct pedal and TPS voltages?
- Which ECM is recommended for an LS swap?
Wiring & computer questions
- Best LS swap wiring harness
- Stock PCM vs Holley Terminator X for an LS swap
- How do I tune an LS swap? (HP Tuners basics)
- How to make a standalone LS wiring harness
- VATS delete: what it is and how to do it
- Drive-by-wire vs cable throttle for an LS swap
- How do I wire a Vintage Air trinary switch into a 3-relay dual electric fan setup with the LS PCM?
- Does it matter which drive-by-wire pedal I use with an LS DBW throttle body?
- Why does my 6.0L LS swap crank but not start?
- How do you keep the stock cluster and tach working behind an LS/4L60E without cutting the factory harness?
- How does the LS PCM control dual electric fans, and is it enough for an old truck with A/C?
- How do you convert a factory 4L60E engine/transmission harness to control a 4L80E when swapping transmissions behind an LS?