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Old 03-07-2008, 04:04 AM   #1 (permalink)
cfg83's Avatar
Join Date: Dec 2007
Location: Southern California
Posts: 5,864

1999 Saturn SW2 - '99 Saturn SW2 Wagon
Team Saturn
90 day: 40.49 mpg (US)
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My Eagle Research EFIE

Hello -

This is something I said I would post in this thread :

Any one seen these DIY gauges?

I have had this gizmo online since August 8, 2007. It's not always on. I try to use it in situations where my (ScanGauge) TPS is below 20 :

Electronic Fuel Injection Enhancer (EFIE) Device

I am monitoring it's behavior with this :

Digital Fuel Mixture Display Kit for Cars

It is connected as follows :

Here is a youtube of it in action :

EFIE Gizmo

In the above video, the EFIE setting is "mild" when it is on. I am trying to add a small fuel trim that still allows for moderate acceleration.

Here is my interpretation of what I am seeing with the EFIE. When the EFIE is on, the A/F ratio creeps up to 14.7 + deltaT. The deltaT is a function of how high I set the EFIE. But, I also have a second post-cat 02 sensor that is used to manage emissions. Because the second 02 sensor is telling the ECU/PCM that the car exhaust is running lean, I think the ECU/PCM tries to resolve the difference by jumping back to 14.7, and then creeping up again. Therefore, I think the result of the EFIE is that instead of floating close around a "narrow ratio" of :

14.7 +- .2

It is now floating around the deltaT with a much wider span :

(14.7+deltaT) +- deltaT

What this means for my EFIE is that I still go back to 14.7, but I spend alot of time "floating up" above 14.7 before going back down.

Notes :

- Since the ScanGauge does not use the short/long term fuel trims, I don't think it is registering the effect.

- I don't like the teeny-tiny screw. It would be nicer if it had something I could tap into. If the screw was on the opposite side, at least it would be easier to package with a hole for inserting a small screwdriver.

- It's output-bias-voltage is temperature sensitive. I wouldn't mind this, except for the fact that I didn't find out until after I bought it. That detail should be on the website. I currently have a CPU heatsink attached to it.

- I have toyed with the idea of a "no load" option. If I tap into the TPS signal, I can make it so that it will only be on when the TPS is zero, and off when I accelerate. That way, the engine would simulate "diesel going lean" under idle/no load conditions.



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Last edited by cfg83; 08-23-2009 at 10:42 PM.. Reason: Moving pix to emissions album
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