[Diy_efi] Making a fake O2

[Adam Wade]

--- David Cooley <n5xmt at bellsouth.net> wrote:

> Once the criteria are met for closed loop, unless
> you are in decel fuel cutoff or WOT, it IS in closed
> loop.

Yes, that is what I just said.  Closed-loop occurs at
idle and at part-throttle cruise.

> And Most cals use the correction in the lonmg term
> fuel trim to ADD fuel to the WOT fuel... If you
> never go closed loop, you never learn a correction
> and can too easily lean out and smoke the engine.

I couldn't disagree more.  As previously stated, many,
MANY engines run just fine without an O2 sensor
installed, and I don't see them blowing up at any
greater rate than vehicles with an O2 sensor.  The
purpose of BLMs is to keep emissions low as the
vehicle ages; some people use it as a tuning device
when making changes to engine and mapping, but the
whole idea is that the engine should, ideally, be
running without any changes showing in the BLM tables.

As injectors age, deposits compromise their spray
pattern and reduce their flow.  Fuel filters slowly
clog.  Fuel pumps slowly lose efficiency.  This is
most likely why you see older vehicles showing
increasing BLM tables.  Clean the injectors and
replace the fuel pump and filter, reset the BLMs, and
see what the ECU comes up with (assuming that the O2
sensor is in good repair).

| 82 Honda CX500 Turbo (Cassandra)  90 Kwak Zephyr 550 (Daphne) |
| "It was like an emergency ward after a great catastrophe; it  |
|   didn't matter what race or class the victims belonged to.   |
|  They were all given the same miracle drug, which was coffee. |
|   The catastrophe in this case, of course, was that the sun   |
|     had come up again."                    -Kurt Vonnegut     |
| M/C Fuel Inj. Hndbk. @ Amazon.com -  http://tinyurl.com/6o3ze |


		
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