Thread: EFI Options

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That's why you have an O2 and water temp sensor

True Dave.The thing I am talking about is a example of Roger who is trying to get the tune down on his EFI.I am sure his set-up has a o2 sensor and temp sensor. He is still working on his fuel curve and ignition advance.What Roger is doing is not uncommon for the aftermarket systems.
I think one of the key questions I am asking is if there are self learned systems,then why are there tuning opportunities over and above that??.

Originally Posted by 1gary

True Dave.The thing I am talking about is a example of Roger who is trying to get the tune down on his EFI.I am sure his set-up has a o2 sensor and temp sensor. He is still working on his fuel curve and ignition advance.What Roger is doing is not uncommon for the aftermarket systems.
I think one of the key questions I am asking is if there are self learned systems,then why are there tuning opportunities over and above that??.

I think it really depends on whose and which system you use-there are many flavors out there, from the EZ-EFI from FAST (which self tunes and has few parameters) to the FAST XFI, Motec, Big Stuff, Edelbrock and the Holley offerings-

The main reason so many offer the tunability is that not all of them have a self-learn feature, and some fo the few that do leave something to be desired-some have very few parameters that can be adjusted that it's barely above what the Factory offers (which is very little in terms of adjustability for the average user, and, will void the Warranty if performed)-

On top of that, you might want to consider Processor speed (which determines how fast it can "adjust"), and the expandability of those options-right now, Holley has the fastest Processor (for an Aftermarket unit), but that won't last for long-aftermarket EFI is such a growing, evolving and quickly expanding market that I think there will be expansion into OEM types of control (Navigation Systems, "Onstar" types of programs and other features)-I think the sky is the limit, as Traction control, data aquisition, nitrous/boost control and so many more options are already available-

It is certainly an exciting time to be a hotrodder-

if the prices ever get below what i paid for my new engine.
i might consider it....

1. My spark map was frozen more than a year ago, and has not been touched since.
2. My A/F map for operation has been in final form for almost that long, but I did go in and lean out the idle area in the last couple of weeks, based on some analysis with my secondary wide band O2 indicator that I use for tuning (see 4).
3. My system uses a narrow band O2 sensor for ECU input, which also drives the red/amber/green LED's on the hand held calibrator which indicate Lean/Ideal/Rich A/F conditions. This is very nearly a digital switch, but does have a narrow range of A/F.
4. What I have continued to "play" with for the past year are the correction curves for 1) Crank Fuel vs Coolant Temperature, which controls fuel input during cranking and thus the startup response; and 2) Injection vs Coolant Temperature, which equates to a carburetor choke and controls warmup idle and operation while warming; 3) Idle Speed vs Coolant, which is the fast idle for warmup, and 4) Accel/Decel vs Coolant, which equates to the accelerator pump volume for transitions. These are relatively minor tweaks, but they have major impact on driver smiles.

Any system, whether self learn or owner tuned will "adjust" from the base maps to account for changes in barometric pressure (altitude or weather) via the MAP sensor; and for ambient temperature via the Inlet Air Temperature sensor. Self learn simply establishes the base spark and A/F maps based on the parameters set in the learning module. As self learn systems are evolving the developers are learning of the shortfalls, including areas where they may not want the ECU to "learn" because it's in an abnormal situation. Also, self learners have limits on all parameters, and it may be prudent for an owner to over-ride those limits based on his/her specific engine. All self learns, whether OEM or aftermarket, are built for specific applications. The aftermarket feature is going to be for broader applications, and as such will be more conservative - read this more reason to have the ability to "adjust" once it thinks it's done.

Regarding OEM ECU's, unless you're looking at picking up an engine/tranny/ECU package from something not more than two to three years old the features of the programming will be very nearly obsolete, and you will do much better with an aftermarket brain, like one from FAST, or some of the "generic's" like Big Stuff3, MegaSquirt 3, and others. This is especially true if you've made modifications to the engine. Just my $0.02 on the EFI process, and I don't think I can add much more to the discussion.