[Diy_efi] Making a fake O2

David Cooley n5xmt
Tue May 31 11:33:52 UTC 2005 

On the american cars I have dealt with, O2 can manipulate the fuel tables by
+- 30% or more, usually with a check engine light at the 20-25% point
depending on the cal...  I can't see 25% or more as being only a few percent
and being insignificant... I have actual GM cal docs for these, and I have
reverse engineered other manufacturer cal's to see what they are doing as
well.
My 97 dodge ram, with STOCK injectors was made pig rich in the base cal and
the O2 corrections were pilling 12-13% fuel at idle and part throttle... WOT
is not corrected by an O2 that is removing fuel, but IS corrected in the
chrysler and GM cals by an O2 that is adding fuel to the base maps... All in
preservation of the engine, not cat efficiency.


> -----Original Message-----
> From: diy_efi-bounces at diy-efi.org 
> [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Gianmarco 
> Rizzo (BE/EAS)
> Sent: Tuesday, May 31, 2005 6:35 AM
> To: diy_efi at diy-efi.org
> Subject: RE: [Diy_efi] Making a fake O2
> 
> David, i am no engineer, but in my limited experience with 
> EFI's, damaging an engine just by use or misuse of a O2 
> sensor can be achieved only by dropping the sensor in the 
> inlet manifold while the engine is running.
> 
> those who design EFI's and those who integrate them on 
> engines know their business. O2 sensors can only correct 
> fueling by a few % and maps are usually conservatively 
> designed, so that any sensor failure won't damage the engine. 
> i have a high performance turbocharged italian sportcar, 
> which would be the perfect candidate for your theory. and i 
> can assure you, there is NO way of damaging the engine by 
> manipulating the O2 signal.
>  
> > -----Original Message-----
> > From: diy_efi-bounces at diy-efi.org
> > [mailto:diy_efi-bounces at diy-efi.org]On
> > Behalf Of David Cooley
> > Sent: Dienstag, 31. Mai 2005 03:53
> > To: diy_efi at diy-efi.org
> > Subject: RE: [Diy_efi] Making a fake O2
> > 
> > 
> > No, Adam is saying that the factory base fuel maps will NEVER cause 
> > problems if a vehicls is run in open loop only with NO O2 
> corrections.
> > I have seen melted pistons in engines that had bad O2 
> sensors and the 
> > owners "fix" was to remove the service engine soon lamp...
> > According to Adam, this never happens and he is actually telling 
> > someone that wants to run open loop only that it will cause no 
> > damage... He must have a good attorney for being able to give that 
> > advice...
> >  
> > 
> > > -----Original Message-----
> > > From: diy_efi-bounces at diy-efi.org
> > > [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Mike
> > > Sent: Monday, May 30, 2005 1:28 AM
> > > To: diy_efi at diy-efi.org
> > > Subject: RE: [Diy_efi] Making a fake O2
> > > 
> > > At 11:53 AM 30/05/05, you wrote:
> > > >Ah, so your experience is a global observation on everything...
> > > 
> > > David, this is not *everything*, this is a specific 
> technical list 
> > > where people are generally technical and that usually means they 
> > > have a background in high school physics, chemistry and maths and 
> > > move on to higher studies such as engineering, masters or even a 
> > > PhD...
> > > 
> > > The side effect of any technical discipline is the huge 
> benefit this 
> > > allows to rationalise most phenomena in combination with 
> industrial 
> > > and commercial complexity as they all come back to 
> scaffolding upon 
> > > the fundamentals of physics and chemistry...
> > > 
> > > Engines are not that complex really, there are 
> combinatorial issues 
> > > which are sometimes way beyond most people who have never had the 
> > > opportunity to get the basic groundwork of physics and chemistry 
> > > sorted out at an early point in their development. Plus 
> it helps to 
> > > occasionally suspend personality so one can launch into abstract 
> > > notions with less limitation.
> > > 
> > > There's also nothing wrong with enjoying a good hard 
> nosed technical 
> > > speculation from time to time either ;-)
> > > 
> > > >You must be a legend in your own mind! 
> > > 
> > > Do I hear knee jerk reaction from a battered ego...
> > > 
> > > <chuckle>
> > > 
> > > Mike
> > > 
> > > 
> > > 
> > > 
> > > 
> > > >> -----Original Message-----
> > > >> From: diy_efi-bounces at diy-efi.org 
> > > >> [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Adam Wade
> > > >> Sent: Sunday, May 29, 2005 10:11 PM
> > > >> To: diy_efi at diy-efi.org
> > > >> Subject: RE: [Diy_efi] Making a fake O2
> > > >> 
> > > >> --- David Cooley <n5xmt at bellsouth.net> wrote:
> > > >> 
> > > >> > If your injectors are starting to have reduced flow due to
> > > >> deposits,
> > > >> > low fuel pressure etc, the stock maps are NOT going 
> to be safe.
> > > >> 
> > > >> Most Honda factory turbo motorcycles have never had their
> > > injectors
> > > >> cleaned, and many are operating with fairly clogged fuel
> > filters.  
> > > >> I've never seen nor heard of any engine problem on ANY
> > > Honda turbo,
> > > >> for ANY reason.  They run open-loop, and have been in
> > > service since
> > > >> 1982.
> > > >> 
> > > >> If turbocharged motorcycle engines can handle it, I daresay 
> > > >> normally-aspirated applications will be quite safe when
> > > operated in
> > > >> open-loop without BLM, unless the maps themselves are pretty 
> > > >> horrible.
> > > >> 
> > > >> > The O2 sensor is there to correct for changes in
> > > >> airflow/fuel flow etc
> > > >> > in the engine to keep the A/F where the manufacturer
> > specified...
> > > >> 
> > > >> No, the O2 sensor is to command a stoichiometric 
> mixture during 
> > > >> low-load steady-state operation.  One of the added
> > > benefits that has
> > > >> come with that is the
> > > >> (limited) ability for a manufacturer to partially
> > > compensate for age
> > > >> via the use of BLM tables.  Prior to the emissions
> > > requirements that
> > > >> demanded a three-way catalyst and long-life emissions
> > components,
> > > >> there were no oxygen sensors used in fuel injection.
> > > >> And if it was really that advantageous, then every 
> fuel-injected 
> > > >> motorcycle made in the past 10 years would have an O2
> > > sensor.  You'll
> > > >> note that most of them don't, and the ones that do only
> > > did so when
> > > >> the EMISSIONS requirements were raised to the point where
> > > closed-loop
> > > >> running with a catalyst was necessary.
> > > >> 
> > > >> > If you take a vehicle that isn't brand new, and run it
> > > in open loop
> > > >> > with no corrections, then yes, the open loop maps MAY
> > > cause damage.
> > > >> 
> > > >> So all us motorcycle riders who got injected bikes without
> > > O2 sensors
> > > >> can sue the manufacturer for making self-destructing
> > > engines?  Cool!
> > > >> 
> > > >> Frankly, since both open- and closed-loop running depend
> > > on the same
> > > >> ingition tables, any fuel maps that would "damage"
> > > >> an engine when it was older would also be very likely to
> > damage it
> > > >> when new.  Further, think about where best-power fuel
> > > mixture is, in
> > > >> terms of potential engine damage...
> > > >> 
> > > >> Somehow, I am certain that those creating the fuel maps for 
> > > >> automotive OEs are not neary as horribly stupid as you're
> > > saying they
> > > >> are.
> > > >> 
> > > >> | 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 |
> > > >> 
> > > >> __________________________________________________
> > > >> Do You Yahoo!?
> > > >> Tired of spam?  Yahoo! Mail has the best spam 
> protection around 
> > > >> http://mail.yahoo.com
> > > _______________________________________________
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> > > >> 
> > > >
> > > >_______________________________________________
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> > > 
> > > Regards from
> > > 
> > > 
> > > Mike Massen
> > > Perth, Western Australia
> > > VL Commodore Fuse Rail that wont warp or melt !
> > > http://niche.iinet.net.au
> > > 
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