VE Table Not Dialed? Send Me Your Datalog.

[X-cam34]

# VE Table Tuning — What I Need From You

I've built a tool that analyzes your MegaSquirt datalog and tells you exactly what your VE table should be.

**To run your tune I need 5 things:**

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**1. Screenshot of your injector dead time table**

In TunerStudio: Go to Fuel → Injector Dead Time. Screenshot the entire table. I need to see the voltage vs dead time values.

**2. Injector size and brand**

Tell me exactly what injectors you're running. Example: "Ford Racing 24lb", "Deatschwerks 42lb", "ACCEL 30lb", etc. If you know the flow rate at a specific pressure (e.g., 24 lb/hr @ 43.5 psi), include that.

**3. Your VE table — copy/paste into a text file**

In TunerStudio: Go to Fuel → VE Table 1. Right-click the table → Select All → Copy. Open Notepad, paste it, save as a .txt file and upload it. I need the raw numbers, not a screenshot of this one.

**4. A datalog — .mlg file from MegaSquirt**

Record a datalog in TunerStudio while driving. The more driving conditions you cover, the better the results:

- Idle for 30-60 seconds (warmed up)
- Normal city driving with moderate acceleration
- Highway cruise at a few different speeds
- A few WOT pulls if you're comfortable (2nd or 3rd gear, safe location)
- Some deceleration / coast down

**Important:**
- Engine needs to be fully warmed up before you start logging (coolant temp 160°F+)
- Wideband O2 sensor required — narrowband won't work for this
- Log needs to include at minimum: RPM, MAP, TPS, AFR, EGO cor1, Accel PW
- .mlg format only — this is what TunerStudio saves by default
- 10-15 minutes of driving is plenty, longer is better

**5. Screenshot of your VE table (the colored grid view)**

This one IS a screenshot. I need to see your RPM and MAP breakpoints along the axes. Go to Fuel → VE Table 1 and screenshot the full table with the axis labels visible.

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**What you get back:**

A corrected VE table you can paste directly into TunerStudio, plus a full diagnostic report showing every cell — what changed, why, how confident the correction is, and which cells need more driving data.

To be clear — I am not adjusting your AFR targets, your timing, or anything else. This tool only corrects your VE table to hit whatever AFR targets you already have set. That's it. If your targets are wrong, that's a separate conversation that I'm not having here. Please don't ask me about spark tables, injector sizing, idle issues, boost targets, or anything outside of VE. I will not respond to it. VE table corrections only.

Hit me up if you have questions.

 

[gkomo]

Since you seem very knowledgeable with megasquirt, can you tell me what it does/doesnt doesn’t do with emissions equipment? I.e. EGR, smog pump, etc.

I am really interested in the megasquirt once I go bigger than my current setup and have been watching a bunch of videos about it but am curious if it’s a hard no on passing emissions or if they just say not emissions legal because they didn’t want to pay for an E.O. number.

 

[X-cam34]

MegaSquirt doesn't control any emissions equipment natively — no EGR valve control, no smog pump, no catalytic converter monitoring, no EVAP purge. It's a fuel and spark controller. Some of that hardware can be wired to spare outputs and controlled with custom logic, but it's DIY and there's no OBD-II readiness monitor support. It won't set or clear emissions codes because it doesn't speak OBD-II the way a factory ECU does.

Appreciate the interest but I'm keeping this thread strictly to VE table corrections — I'm not really the guy to ask about emissions equipment and MegaSquirt compatibility. There are some solid threads on that topic already if you search around. If you ever need your VE table dialed in though, hit me up.

 

[gkomo]

Thanks! Sorry for the derail.

 

[GOvert]

@X-cam34 What brand of ecm are you using?

 

[X-cam34]

TunerStudio 3.2.0

I've been building my own VE correction tool that reads your datalog and calculates what every cell in your VE table should actually be based on your wideband and EGO correction data. You feed it a log and your current table, it spits back a corrected table ready to paste into TunerStudio.

I'm currently gathering data across as many different setups as possible — different engine sizes, injector configs, NA, boosted, whatever. The more edge cases I can find and handle now, the better the tool is when it launches.

Example:

Cell: 4400 RPM x 60 kPa (Row 9, Col 9)
Current VE: 121
AFR Target: 14.34
AFR Actual (avg): 15.19
AFR Min/Max: 12.50 / 17.20
AFR Std Dev: 1.26
AFR Error: 0.84
EGO Correction (avg): 103.8%
EGO Correction (median): 104.0%
EGO Samples: 32 (3 open-loop frames filtered)
EGO Deviation: +3.75%
VE Error (from EGO): +3.75%
Status: LEAN
Samples: 15 valid, 1.3717000000000006 fuel cut
Confidence Level: Low (54 hits) (15 samples)
Correction %: 22.5% (EGO-driven)
Suggested VE: 121
Status: APPLIED (was 120 → now 121)
Full correction VE: 125

 

[X-cam34]

What this tool does, for those who think "yeah tuner studio does this already"

 

[X-cam34]

Not getting any bites so i figure i would show a before and after of a VE table of a car i tuned.

 

[X-cam34]

That is about 2-3 hours of drive time, a few passes with the tool. This is exactly what the ECU wanted my tool listens to what the ECU is telling and applies fixes. Chasing with Auto and VE tune would never yield results like this

 

[86HO5.0]

This is a great idea! I'll have to send a datalog and copy of my tune to you and see what this tool comes up with. My tune is close enough that I can drive in open loop or utilize 3% EGO correction.

Autotune will get the tune 60-80% of what's ideal IMO. Too many people rely on Autotune and leave ALOT of performance on the table.

I helped a guy with his Holley EFI tune a couple years back, his 'tuner' had EGO correction set at 50%.

 

[X-cam34]

Sounds good — send it over. I'll run it through the tool and send you back a log showing exactly where you're at. From there it's your call whether to apply the corrections. Looking forward to seeing what a tune that's already close looks like through the tool.

 

[X-cam34]

And yeah, that's exactly why I built this thing. Autotune flip-flops — it corrects a cell one direction, then over-corrects the other way next pass, and you end up chasing your tail. My tool accounts for that and locks corrections down so you're not going in circles. Looking forward to seeing what a tune that's already close looks like through it.


Edit: The plan is to release it with a monthly license for $15 — that's 50 cents a day. Drive your car, upload your log, and it spits out a corrected VE table. Right now I'm just gathering data across different setups to make sure I've got all the edge cases covered before launch.

 

[X-cam34]

@86HO5.0 what about them logs?

 

[86HO5.0]

Working on that now.

Ford 30lb injectors, factory psi (39 IIRC).

I have one good data log taken right before my last trip to the dyno. It's only a couple minutes long, but it covers everything pretty well.

Some of my AFR targets are slightly off from where it's tuned, I've never corrected it.....not sure why.

 

[86HO5.0]

Datalog. This was taken the day before my 281/326 dyno results.

 

[86HO5.0]

VE Table and injector dead time. Tuner studio won't allow select all, copy/paste to a text file. Doesn't give that option.

 

[86HO5.0]

The other datalogs I have archived are between 1% and 3% EGO correction. The log from 9/6/23 is my 'sloppiest' one.

I can send a copy of my tune if needed.

 

[X-cam34]

Sorry for the late reply.

I need to make sure the VE table and the datalog were from the same session. You mentioned the datalog was taken the day before your 281/326 dyno results — does the VE table screenshot you sent match what was loaded when that log was recorded? If the VE table is from after the dyno session, the corrections will be off because the tool is calculating based on what the ECU was running at the time of the log.

For the VE table copy — open your VE table in TunerStudio, left click and hold, drag to highlight the entire table, then right click → Copy (or Ctrl+C). Paste that into Notepad and save it as a .txt file. If that still gives you trouble, just send me the tune file and I'll pull it out myself.

Once I know the log and VE table are in sync I'll run it through the tool.

Edit: If you still have issues with getting the copy and paste, just send me the tune.

 

[86HO5.0]

I double checked the VE table, there were a couple very minor adjustments outside of the idle cells. Here's the VE table from that datalog.

Attached is the requested txt file.

FYI--I don't run EGO correction below 1200rpm.

 

[X-cam34]

Ok, I will go over this tonight, things have been really busy here.