Frequently Asked Questions

You upload a datalog and tell us about your build. TuneDoc reads the log and writes a plain-English report on idle quality, fueling, timing, temperatures, charging and full-throttle behavior: what the engine is doing, what's most likely causing any problems, and where to look to fix them. It works with Holley Terminator X / Terminator X Max / Dominator logs and HP Tuners VCM Scanner logs.

About a minute. The report is generated as soon as you upload — no waiting a day for someone to get back to you — so you can make a change, re-log and check it again in the same afternoon.

Small-block Ford Windsor engines (302, 331, 347, 351W and 351W strokers) and GM LS engines (4.8, 5.3, 5.7, 6.0 including the LS2, 6.2 including the supercharged LSA/LS9, 7.0 and LS strokers) on Holley EFI. The same LS engines are supported with HP Tuners. Both cable throttle with an IAC and drive-by-wire are covered. Pick the right engine when you add your vehicle — it decides how TuneDoc reads your log.

Yes for Holley logs — boost analysis is new and in beta. When your log goes into boost, the report adds a Boost tab: how boost builds and holds, fueling and timing in boost, whether fuel pressure keeps up with boost, how hard the injectors are working, and intake air temperature. Running lean, knock or a fuel supply problem in boost is also flagged as a safety concern. Pick your setup (turbo, centrifugal or roots/twin-screw) under Forced Induction when you add the vehicle. Boost isn't judged on HP Tuners logs yet; everything else in those logs still is.

Start the log cold if you can, let it idle until it's warm, then drive normally for 5–10 minutes: stops, cruising, a few easy pull-aways and, if it's safe and legal, one full-throttle pull through a gear. Come back to idle at the end. Very long logs can be too big to upload — 5–10 minutes is plenty.

Treat it like a second opinion from an experienced tuner: a great place to start, not the final word. The measurements come straight from your log; the likely causes are the best read of that data, and the report says what to check to confirm them. Reports are generated automatically and can be wrong. Make one change at a time, re-log, and have anything major checked by a professional. See our Terms of Service.

Yes. Datalogs, tune files (if you upload one), vehicle details and reports are saved to help run and improve TuneDoc. We don't sell your information. Details are in the Terms of Service, and you can ask us to delete a report by sending its Report ID through the Contact page.

Every report gets a short ID like TD-7K3M-9QX2, shown at the top of the report and on the PDF. Include it whenever you contact us about a report so we can find it quickly.

Open the Holley EFI software on your laptop and open the datalog. Go to File → Export Datalog → CSV, save the file, then upload that .csv file to TuneDoc along with your .terx tune file.

TuneDoc reads your injector size, IAC type and idle settings straight from the tune, so you don't have to enter them. Upload the .terx tune that was on the car when the log was recorded. TuneDoc checks the tune against the log and only uses settings it can confirm, then adds a Tune Review to your report. If the tune doesn't match the log, it isn't used. TuneDoc never changes your tune.

Older Terminator X software saved tunes in a format TuneDoc can't read. Open the tune in the current Holley EFI software, use File → Save As, and upload the newly saved .terx.

No. TuneDoc is an independent tool built by an enthusiast. It isn't made by, affiliated with, or endorsed by Holley Performance Products. It works with datalogs and tune files exported from Holley's Terminator X software, and Holley product names are used only to say what TuneDoc works with. For questions about your ECU or Holley's software, contact Holley directly.

Yes, for GM LS engines on a GM PCM. When you add your vehicle, pick the engine and set the ECU to HP Tuners (GM PCM). TuneDoc analyzes the VCM Scanner datalog: fuel trims by area and an RPM × load trim map, idle quality and idle target, idle hang, returning to idle, pulling away from a stop, MAF vs. VE airflow, timing and knock, O2 sensor health, a wideband if you log one, full throttle, temperatures and charging.

Open the log (.hpl) in VCM Scanner, use its export to save the log as a .csv file, and upload that .csv. TuneDoc can't open .hpl files directly.

HP Tuners tune files are locked to HP Tuners' own software, and TuneDoc doesn't try to open them. So HP Tuners reports are built from the datalog alone: there's no tune review, and the report never quotes values from your tune. It tells you what the log shows and which part of the tune to look at — the main tables by their common names, like the MAF calibration, the VE table, Base Running Airflow or Power Enrichment.

TuneDoc has been checked against logs from Gen III (0411 / P01 / P59) and Gen IV (E38 / E67) PCMs. It matches channels by their VCM Scanner channel number, so most GM PCMs that log the usual channels work. If yours is missing something, the report lists what to add.

The more of these, the better the report: Engine RPM, Vehicle Speed, Short and Long Term Fuel Trims (both banks), Fuel System Status, Intake Manifold Absolute Pressure, Timing Advance, Knock Retard, Engine Coolant Temp, Intake Air Temp, Idle Desired RPM, Idle Desired Airflow, Mass Airflow, Volumetric Efficiency Airflow, O2 Voltage B1S1 and B2S1, Control Module Voltage and Trans Current Gear. Cable throttle: add Idle Air Control Position and Throttle Position Sensor (volts). Drive-by-wire: add Accelerator Pedal Position and Throttle Desired Position. If you have a wideband wired into your MPVI, log it too. After each report, the box under the Virtual Crew Chief lists anything your log was missing.

When you pick HP Tuners, the vehicle form asks a few quick questions — throttle type, MAF or speed density, injectors, wideband, PCM and who tunes the car. You don't need to open your tune to answer, and "Not sure" is fine. The answers help aim the advice (for example, no MAF advice on a speed-density car). If the log shows something different, TuneDoc goes with the log.

No. TuneDoc isn't made by, affiliated with, or endorsed by HP Tuners. HP Tuners and VCM Scanner are named only to say what TuneDoc works with.