Self-Tuning Fuel Injection

[davepl]

Does anyone have experience with any (or ideally, more than one so you can compare) of the self-learning fuel injection systems?

I'm trying to get a feel for how "good" their learning is for a few things, such as:

- Just getting the base map (VE) table right for each load v RPM cell
- Getting tip-in enrichment (like an accelerator pump) right
- Timing

It'd be pretty easy to do the first bullet point. The second one is harder, the computer would have to try various amount of enrichment and look for a bog to occur a little -later-, which makes it harder code to write.

Without a knock sensor I presume no timing "self-learning" is possible, correct? Do any of them actually do it with a knock sensor?

Thanks!
Dave

[Heavymetl]

The term "self tuning" is basically a marketing scam. All self tuning does is build a fuel map based on a closed loop system from idle to WOT.

Timing, acceleration enrichment, cold start, idle quality parameters, and so forth still need to be conventionally tuned. Don't get me wrong, letting the computer build a fueling table is awesome, but there's just so much more to it as you've assumed in your post.

The greatest benefit in using aftermarket EFI as opposed to factory PCMs is the simplicity. 1 timing table, not 12. Easy to understand tables rather than confusing g/sec here, map vs kpa there, etc.

[Wasted Income]

^ Nailed it.

[davepl]

Seriously? So all it does it tune the base map? That blows - at some ratio of 0 to 100% blowage, to be determined during closed loop.

I assumed that it'd self-learn for accel, coolant temp, air temp, and the basics at least! Thanks!

[Matt Cramer]

The Tune Analyze Live feature in TunerStudio has a self learning coolant temperature feature in addition to changing the main fuel table. But acceleration enrichment is nearly impossible to pull off good self learning with because (1) this only fires for a short burst and (2) it's fairly easy to tune it wrong in such a way that a misfire gives a false lean reading.

Autotuning an ignition table is even harder. A lot of engines don't knock until the timing is well advanced past what it needs to be.

[invicta455]

so if im correct for extra fine tuning your still going to have to go in with a laptop

[Wasted Income]

Yes.

[invicta455]

wasted income could you give me some pointers to look for i have the holley efi termanator

[cleszkie]

I run the MSD Atomic throttle body EFI. I have it controlling the fuel and timing with a locked out dizzy and 6al ignition box. Upon initial set-up, it basically gives you the choice of three base fuel maps depending on the cam profile (lift/duration/lobe separation) you are running - Street/Stock, Mild, and Performance. The system will then modify the base fuel map according to the system feedback. The sensors include TPS, O2, coolant temp, intake air temp, MAP, etc. In the advanced set-up menu, you have the ability to manually adjust the accelerator pump shot, and power valve enrich settings to get things where you want them. I found that the system was limited in its ability to totally manage my engine until I let it control the timing as well (and install a return style fuel system with in-tank pump, but that is another story). Now it can much better optimize the timing/fuel requirements.

In a nutshell, it is a self learning system, but there is a lot of tweaking and adjustments that must be made to fully realize the potential of the system. The MSD Atomic comes with a plug in hand held display that allow the user to make the adjustment on the fly without having to use a laptop.

[davepl]

I would think you could tune Accel Enrichment as follows:

- Start with base value (extra 5ms for 100 revolutions)
- Monitor AFR for 2X the enrichment length
- Determine whether you went lean or rich over the period
- Adjust the base values, weight it, repeat

You'd of course actually need a 2D table at least so that you have TPS delta amount and enrichment amount.

Sounds simple on paper, I guess if I were smart I'd build a Megasquirt and write my own code!

[kpeztruck]

I used the MSD Atomic EFI on a '56 Belair. This was an all number matching car, so the customer did not want any new holes or large modifications. I used it returnless and set everything up. Still using the factory distributor with an electronic conversion that had been previously installed. It developed a terrible bog at part throttle, and would stall at the most inopportune times. The A/F ratio would show 18-24:1 when in condition. After talking with techline(and there is one guy that is sharp on these things), setting everything up as he desired, he decided that my kit did not come with an addendum to install a fuel pressure isolator from a Honda that would prevent surges in fuel pressure. he said that the ECM was making decisions on a measured fuel pressure, then by the time the action was carried out, the fuel pressure dropped and it did not get enough fuel. Installed the isolator as instructed and now the car runs great. Customer is real pleased with performance and fuel mileage. The tech guy did say that it will auto tune, but if the info/manual calibration adjustments start off incorrect, it will tune itself into a corner as mine did. Overall, I'd do another one for a driver hot rod.

[Wasted Income]

Originally Posted by invicta455

wasted income could you give me some pointers to look for i have the holley efi termanator

It is going to depend on what mods you have, and how it runs as to what tuning tweaks to make.

How does it start up cold? Warm?

Are there any flat spots or stumbles during tip-in?

Does it idle well? At an RPM that you're happy with?

etc, etc, etc.

I'd be happy to help if you have some specific questions.

[Wasted Income]

Originally Posted by kpeztruck

The tech guy did say that it will auto tune, but if the info/manual calibration adjustments start off incorrect, it will tune itself into a corner as mine did. Overall, I'd do another one for a driver hot rod.

See that's the problem though. It won't *tune* itself. I will *learn* corrections to the base fuel map to make the actual AFR as close to the commanded AFR as possible. Like others said, it will not "tune" the ignition timing, or any other parameter...it will simply follow what has been programmed.

[LostMy65]

Originally Posted by cleszkie

I run the MSD Atomic throttle body EFI. I have it controlling the fuel and timing with a locked out dizzy and 6al ignition box. Upon initial set-up, it basically gives you the choice of three base fuel maps depending on the cam profile (lift/duration/lobe separation) you are running - Street/Stock, Mild, and Performance. The system will then modify the base fuel map according to the system feedback. The sensors include TPS, O2, coolant temp, intake air temp, MAP, etc. In the advanced set-up menu, you have the ability to manually adjust the accelerator pump shot, and power valve enrich settings to get things where you want them. I found that the system was limited in its ability to totally manage my engine until I let it control the timing as well (and install a return style fuel system with in-tank pump, but that is another story). Now it can much better optimize the timing/fuel requirements.

In a nutshell, it is a self learning system, but there is a lot of tweaking and adjustments that must be made to fully realize the potential of the system. The MSD Atomic comes with a plug in hand held display that allow the user to make the adjustment on the fly without having to use a laptop.

What model msd distributor are you using?