Auto Speed and DFA's

[Zuffen]

I sibscribe to Auto Speed and they are running a series of articles on a Digital Fuel Adjuster (DFA). Essentially what they have is a box of tricks that can alter the output of the AFM to fool the ECU into running richer or leaner fuel ratios.

Form what I inderstand the 1UZ with it's Karman AFM gives out both a voltage and fequency for the ECU to work with.

One of the good points about Auto Speed is they own an LS400 and like using it to do bits and pieces.

They've installed the DFA on the LS400 and proceded to alter fuel ratios. Form what I understood this couldn't be done but who am I to argue when I see this being done.

Will the ECU learn it's way back to the factory settings?

I've emailed off to Auto Speed trying to get some information so hopefully I can give you some answers.

The trick thing is you can buy the DFA in kit form and build it yourself for under $80.00 Australian! Pre-bult and tested versions are up around $250.00. You control it via a hand controller which can also be purchased in kit form.

Looking at it this device should allow you to run the stock ECU with a modified engine. You could use a larger AFM to let it breath and re-tune it with the DFA.

Has anyone else read the article and have any comments.

Let's see some feedback on this.

 

[Lextreme II]

Rod,

This is very interesting. Basically its a piggyback computer alter signals from the afr input to the main ecu. I used an Apexi S-AFC for a while and currently i am using a Split Second. The SS cost about double (450) but it also more control on injectors and timing. Apexi only allow 20% to 30% injectors size increase. I am finding out
the SS can control double to triple of the stock injectors.

The DFA is an interesting and would like to know more. Do u have pictures? Right now i am trying to convert MAF to MAP and delete the MAF.

 

[Zuffen]

David,

As the article is on the Auto Speed Site it's under copyright so I can't post any of it. Well I can but your Site may get into strife so I won't.

In the article it said the DFA could accomodate larger injectors as well.

My thinking is if it can allow me to run bigger injectors I could retain the standard ECU with all it's drivability benefits and run the supercharger.

This would be quite reasonable cost wise and make for a much nicer car to drive.

For the $160.00 (for the DFA and controller kits) I might just buy them so I can post up the instructions for comment.

I'd like to see what KDog thinks of it all.

 

[Lextreme II]

Rod,

Would love to learn more about it. Please let us know more when u get more info.

 

[Damien]

Zuffen, sounds good but you might want to double check that the DFA will work with the Karman AFM. From my investigations into removing the AFM like what David's looking to do it only outputs a square-wave frequency, not a voltage. Would love to be proved wrong though

 

[Zuffen]

Damien,

I agree with you, but Julian at Auto Speed did the mod on an LS400 which as we all know has a Karman AFM.

I also wonder if the ECU re-learns it's old settings?

I've emailed Auto Speed to see if they can enlighten me.

 

[Zuffen]

The DFA works on post '98 vehicles as Toyota did away with the Karman Vortex AFM. Pity they ever used it!

Back to the drawing board.

 

[Damien]

Rod, that's a shame. If you want to keep the stock management then have a look at the MAP-ECU. As I think I mentioned to you before I'll be fitting ITB's to my Soarer but want to keep the stock ECU and this is the only way I've found to do it. Plus you can get rid of the AFM altogether. You can speak to Neil Griffiths about getting the MAP-ECU in Aus... considering you want to get a blower at some point Neil's probably already got it sussed.

 

[Lambo]

Karmen Vortex airflow

Hi Guys, The disscussion you are having is interesting, i have a Mitsi Starion with one of those AFM, when i changed the motor from 2lturbo to 2.6 turbo, all i had to do to get more fuel in was to change the Temperature sensor to the ECU by adding a variable pot, and i could make it as rich or lean as i wanted,it also retarded the spark so i could run more boost. so i got to thinking did it have the same Karmen AFM and it did. so I went digging and came up with this little bit of info as to what signals the Toyota Karmen has here is part of the doc go to page 1 and 3 for more info

KARMAN-VORTEX
SENSOR DIAGNOSIS
Both Toyota/Lexus and Mitsubishi Karman-Vortex
air-flow sensors put out two signals: an air-flow
frequency signal and an air-temperature or
barometric-pressure voltage signal. The Karman-
Vortex signal should be a square-wave signal that
flips back and forth from 0 to 5 volts. The frequency
of the signal will increase (narrower pulse width)
as air flow increases. Frequency should increase
smoothly and steadily with rpm.
Driveability problems such as surging, hesitation,
stalling and elevated emissions may indicate a
sensor failure. Most sensor problems are caused
by a loose or corroded wiring connector.
On the early Mitsubishi applications, the sensor is
mounted inside the air cleaner. A poorly fitting
air filter may prevent the air cleaner lid from fully
seating against the sensor and cause problems.
Similar problems can be caused by air leaks in the
intake plumbing or manifold.
Codes 31 & 32 indicate no signal from the air-flow
sensor on the Toyota & Lexus applications. Code
12 refers to a fault in the air-flow sensor circuit
on Mitsubishi applications.
Hope its of use Lambo
http://www.wellsmfgcorp.com/counterpoints/Counterpoint3_3.pdf